This document summarizes a study that used computational fluid dynamics (CFD) simulations to analyze the aerodynamic characteristics of two re-entry vehicle designs, FIRE II and OREX, at supersonic and hypersonic speeds. The study examined the effects of small changes in flight attitude and vehicle shape on resulting aerodynamic forces. Turbulent flow was modeled using the k-ε turbulence model. Grid sensitivity analysis was performed to validate the CFD simulations. The goal was to better understand how shock waves and aerodynamic forces impact the dynamics and fate of re-entry vehicles during atmospheric re-entry.
A Comparison of Two Kite Force Models with ExperimentGeorge Dadd
This document compares two models for predicting kite line tension - a zero mass model that assumes the kite and lines are weightless, and a lumped mass model that considers the kite's mass using equations of motion. Experimental data is used to validate the models. It is found that the two models converge as kite mass approaches zero, and that kite mass only affects performance to a small extent. The zero mass model compares favorably to experimental results in predicting performance during three-dimensional kite trajectories. Kite propulsion is an attractive way to harness wind power with environmental and financial benefits.
Determination of Kite forces for ship propulsionGeorge Dadd
This document presents a method for predicting kite forces for use in ship propulsion by kites. It describes modeling kite trajectories as figure-eight shapes and using these to calculate kite velocity, force and performance over time. Simulation results show a 300m^2 kite could provide an average propulsive force of 16.7 tonnes in 6.18 m/s wind. The model is used to study how parameters like aspect ratio, elevation angle and trajectory shape impact propulsive performance. Validation with experimental data shows favorable agreement.
Heat Transfer Analysis for a Winged Reentry Flight Test BedCSCJournals
In this paper we deal with the aero-heating analysis of a reentry flight demonstrator helpful to the research activities for the design and development of a possible winged Reusable Launch Vehicle. In fact, to reduce risks in the development of next generation reusable launch vehicles, as first step it is suitable to gain deep design knowledge by means of extensive numerical computations, in particular for the aero-thermal environment the vehicle has to withstand during reentry. The demonstrator under study is a reentry space glider, to be used both as Crew Rescue Vehicle and Crew Transfer Vehicle for the International Space Station. It is designed to have large atmospheric manoeuvring capability, to test the whole path from the orbit down to subsonic speeds and then to the landing on a conventional runway. Several analysis tools are integrated in the framework of the vehicle aerothermal design. Between the others, we used computational analyses to simulate aerothermodynamic flowfield around the spacecraft and heat flux distributions over the vehicle surfaces for the assessment of the vehicle Thermal Protection System design. Heat flux distributions, provided for equilibrium conditions of radiation at wall and thermal shield emissivity equal to 0.85, highlight that the vehicle thermal shield has to withstand with about 1500 [kW/m2] and 400 [kW/m2] at nose and wing leading edge, respectively. Therefore, the fast developing new generation of thermal protection materials, such as Ultra High Temperature Ceramics, are available candidate to built the thermal shield in the most solicited vehicle parts. On the other hand, away from spacecraft leading edges, due to the low angle of attack profile followed by the vehicle during descent, the heat flux is close to values attainable with conventional heat shield. Also, the paper shows that the flying test bed is able to validate hypersonic aerothermodynamic design database and passenger experiments, including thermal shield and hot structures, giving confidence that a full-scale development can successfully proceed.
Optimisation of the design of uav wing j.alexander, Prakash, BSM Augustinesathyabama
The document discusses the optimization of the design of UAV wings. It analyzes two types of rectangular wings using aerodynamic and structural design methods. Aerodynamic analysis using vortex lattice modeling found lift coefficients for the wings. Structural analysis using CATIA found that using composite materials instead of isotropic materials reduced mass by 34%. The optimum design of each wing maximized strength while minimizing mass and displacement.
Numerical Modelling of Wind Patterns around a Solar Parabolic Trough CollectorIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
On assessing the accuracy of offshore wind turbine reliability based designabelkrusnik02
This document discusses assessing the accuracy of design loads derived using the environmental contour method for offshore wind turbines. It compares design loads from this method to exact solutions using full integration over the failure domain. The environmental contour method makes two key assumptions that are often violated: 1) the limit state surface is well approximated by a tangent hyperplane at the design point, and 2) only a single failure mode is considered. This can introduce errors since wind turbine failure can occur under different operating conditions. The document examines these sources of error using an offshore wind turbine located at two Danish sites, Rødsand and Horns Rev, and their differing environmental conditions.
This document discusses optimizing the perilune altitude of a lunar landing trajectory to minimize total energy requirements. It presents the problem description, assumptions, governing equations of motion, formulation as an optimal control problem, and solution approach using a two-point boundary value problem solved via a shooting method. The optimal perilune altitude and thrust profile are determined to minimize the sum of the energy needed for de-orbit burning and descent.
Strategic design of aircraft wings have evolved over time for maximum fuel efficiency. One of such ideas involves winglet which has been known
to reduce turbulence at the tip of the wings. This study intends to investigate the
differences in drag and lift forces generated at aeroplane wings with and without winglet at cruising speed using FEM. Simulations were performed in the
SST turbulence model of CFD and the results are compared to that of the experimental and theoretical models. The simulation showed that the lift increased
by 26.0% and the drag decreased by 74.6% for the winglet at cruising speed.
A Comparison of Two Kite Force Models with ExperimentGeorge Dadd
This document compares two models for predicting kite line tension - a zero mass model that assumes the kite and lines are weightless, and a lumped mass model that considers the kite's mass using equations of motion. Experimental data is used to validate the models. It is found that the two models converge as kite mass approaches zero, and that kite mass only affects performance to a small extent. The zero mass model compares favorably to experimental results in predicting performance during three-dimensional kite trajectories. Kite propulsion is an attractive way to harness wind power with environmental and financial benefits.
Determination of Kite forces for ship propulsionGeorge Dadd
This document presents a method for predicting kite forces for use in ship propulsion by kites. It describes modeling kite trajectories as figure-eight shapes and using these to calculate kite velocity, force and performance over time. Simulation results show a 300m^2 kite could provide an average propulsive force of 16.7 tonnes in 6.18 m/s wind. The model is used to study how parameters like aspect ratio, elevation angle and trajectory shape impact propulsive performance. Validation with experimental data shows favorable agreement.
Heat Transfer Analysis for a Winged Reentry Flight Test BedCSCJournals
In this paper we deal with the aero-heating analysis of a reentry flight demonstrator helpful to the research activities for the design and development of a possible winged Reusable Launch Vehicle. In fact, to reduce risks in the development of next generation reusable launch vehicles, as first step it is suitable to gain deep design knowledge by means of extensive numerical computations, in particular for the aero-thermal environment the vehicle has to withstand during reentry. The demonstrator under study is a reentry space glider, to be used both as Crew Rescue Vehicle and Crew Transfer Vehicle for the International Space Station. It is designed to have large atmospheric manoeuvring capability, to test the whole path from the orbit down to subsonic speeds and then to the landing on a conventional runway. Several analysis tools are integrated in the framework of the vehicle aerothermal design. Between the others, we used computational analyses to simulate aerothermodynamic flowfield around the spacecraft and heat flux distributions over the vehicle surfaces for the assessment of the vehicle Thermal Protection System design. Heat flux distributions, provided for equilibrium conditions of radiation at wall and thermal shield emissivity equal to 0.85, highlight that the vehicle thermal shield has to withstand with about 1500 [kW/m2] and 400 [kW/m2] at nose and wing leading edge, respectively. Therefore, the fast developing new generation of thermal protection materials, such as Ultra High Temperature Ceramics, are available candidate to built the thermal shield in the most solicited vehicle parts. On the other hand, away from spacecraft leading edges, due to the low angle of attack profile followed by the vehicle during descent, the heat flux is close to values attainable with conventional heat shield. Also, the paper shows that the flying test bed is able to validate hypersonic aerothermodynamic design database and passenger experiments, including thermal shield and hot structures, giving confidence that a full-scale development can successfully proceed.
Optimisation of the design of uav wing j.alexander, Prakash, BSM Augustinesathyabama
The document discusses the optimization of the design of UAV wings. It analyzes two types of rectangular wings using aerodynamic and structural design methods. Aerodynamic analysis using vortex lattice modeling found lift coefficients for the wings. Structural analysis using CATIA found that using composite materials instead of isotropic materials reduced mass by 34%. The optimum design of each wing maximized strength while minimizing mass and displacement.
Numerical Modelling of Wind Patterns around a Solar Parabolic Trough CollectorIJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
On assessing the accuracy of offshore wind turbine reliability based designabelkrusnik02
This document discusses assessing the accuracy of design loads derived using the environmental contour method for offshore wind turbines. It compares design loads from this method to exact solutions using full integration over the failure domain. The environmental contour method makes two key assumptions that are often violated: 1) the limit state surface is well approximated by a tangent hyperplane at the design point, and 2) only a single failure mode is considered. This can introduce errors since wind turbine failure can occur under different operating conditions. The document examines these sources of error using an offshore wind turbine located at two Danish sites, Rødsand and Horns Rev, and their differing environmental conditions.
This document discusses optimizing the perilune altitude of a lunar landing trajectory to minimize total energy requirements. It presents the problem description, assumptions, governing equations of motion, formulation as an optimal control problem, and solution approach using a two-point boundary value problem solved via a shooting method. The optimal perilune altitude and thrust profile are determined to minimize the sum of the energy needed for de-orbit burning and descent.
Strategic design of aircraft wings have evolved over time for maximum fuel efficiency. One of such ideas involves winglet which has been known
to reduce turbulence at the tip of the wings. This study intends to investigate the
differences in drag and lift forces generated at aeroplane wings with and without winglet at cruising speed using FEM. Simulations were performed in the
SST turbulence model of CFD and the results are compared to that of the experimental and theoretical models. The simulation showed that the lift increased
by 26.0% and the drag decreased by 74.6% for the winglet at cruising speed.
This document describes the design of a bio-inspired flexible wing for flapping-wing micro air vehicles. The researchers experimentally tested the load-deformation characteristics of hawkmoth wings and used this data to design a synthetic flexible wing with matching deformation properties. Finite element analysis was used to model the structural response of the synthetic wing design. An optimization process then matched the deformation profile of the synthetic wing to that of real hawkmoth wings by varying the vein diameters and moduli in the design. The aerodynamic performance of the flexible synthetic wing was then tested and compared to a rigid wing of similar geometry on a robotic flapper.
Seismic Analysis of Reinforced Concrete Shaft Support Water Storage TankIJERA Editor
This document summarizes a research paper that compares the seismic analysis of reinforced concrete shaft-supported water storage tanks according to two Indian codes: IS 1893-1984 and IS 1893-2002 (Part 2). The analysis was conducted for tanks of 500, 750, and 1000 cubic meters in different seismic zones and soil types. Parameters like base shear, base moment, and time history analysis results were compared between one-mass and two-mass tank models. The 2002 code produced higher base shear values, indicating existing tanks may be deficient. Empty tanks had higher base moments than full tanks. Two-mass models provided a more realistic representation of tank response than one-mass models.
EAGES Proceedings - K. V. Rozhdestvenskii 2Stephan Aubin
In 2001 Euroavia Toulouse organized a symposium on ground effect. We invited most of the Russian and German actors, and some experts from Holland, UK or France for a week of science around the subject of ekranoplans / flying boats. This was dedicated to students. A book was issued... and now that all copies have been sold for a while I am sharing this on LinkedIn for everyone.
Enjoy.
Stéphan AUBIN
Glider Advancements in Efficiency: Enhancing Factors Necessary for Ocean-Wide...LiamRamsay
Research Paper written for the Autonomous Underwater Vehicle (AUV) Teledyne Marine Slocum Glider. Paper was published for the MTS/IEEE OCEANS Conference 2015 Washington D.C.
The Optimization of the Generalized Coplanar Impulsive Maneuvers (Two Impulse...paperpublications3
Abstract: The orbit transfer problems using impulsive thrusters have attracted researchers for a long time [3]. One of the objectives in these problems is to find the optimal fuel orbit transfer between two orbits, generally inclined eccentric orbits. The optimal two-impulse orbit transfer problem poses multiple local optima, and classical optimization methods find only local optimum solution. McCue [7] solved the problem of optimal two-impulse orbit transfer using a combination between numerical search and steepest descent optimization procedures. The transfer of satellites in too high orbits as geosynchronous one (geostationary), usually is achieved firstly by launching the satellite in Low Earth Orbit (LEO) (Parking orbit), then in elliptical transfer orbit and finally to the final orbit (Working orbit). The three steps process is known as Hohmann transfer. The Hohmann transfer which involves two circular orbits with different orbital inclinations is known as non‐coplanar Hohmann transfer. If both orbital planes are aligned the Hohmann transfer is known as coplanar what is further considered in this paper. In terms of propellant consumptions the Hohmann transfer is the best known transfer to be applied when transferring between elliptical coplanar orbits. For transfer between elliptical coplanar orbits, the given information usually consists of the altitude of perigee and apogee of the initial and the altitude of perigee and apogee of the final orbits. The velocity to be applied into two orbit points in order to attain the dedicated final orbit is analyzed.
The aim of this paper is compare between three types of coplanar impulsive transfer (two impulses, three impulses and one tangent burn) and conclude about the velocity changes for these types under relation between initial low Earth altitudes and final orbit. For the relation between initial orbit altitudes and final orbit altitude, the velocities to be applied in process of Hohmann transfer are simulated. From respective simulations, the velocity variations on dependence of this relation are derived. And the time of flight is considered too. The problem of spacecraft orbit transfer with minimum fuel consumption is considered, in terms of testing numerical solutions.
Numerical Investigation of Turbulent Flow Around a Stepped Airfoil at High Re...ROSHAN SAH
This presentation describes a mathematical investigation of turbulent flow around a stepped airfoil. It includes the design of stepped airfoil, airfoil theory, governing equation of turbulence modeling and boundary condition. whereas, results and discussion are shown in second presentation on same topic.
Nwtc turb sim workshop september 22 24, 2008- site specific modelsndkelley
1) The document describes several inflow turbulence models available in the TurbSim code developed by NREL, including models based on standard IEC conditions, smooth homogeneous terrain, specific wind farm sites, complex mountainous terrain, and a North American high plains site.
2) Comparisons of simulation results using the IEC, Great Plains, and NWTC models show differences in predicted blade loads, rotor torque, bending moments and tip deflections when applied to the NREL 5 MW reference turbine.
3) In particular, the Great Plains model including a low-level jet produced significantly higher loads and deflections compared to the standard IEC model, demonstrating the importance of using site-specific models.
Calculation of Fluid Dynamic for Wind Flow around Reinforced Concrete WallsIJERA Editor
A study on the flow phenomena around free-standing walls is important in practical building construction. In the present paper a numerical study is conducted for two- dimensional incompressible steady flow around freestanding walls using low-Re k-co turbulence model. The separation regions downstream the wall and on the roof of the leeward were predicted. Finally, results of numerical simulation are presented in the form of velocity vectors, velocity contour, pressure contours and streamlines
Magnetic sail braking vs two-stage fusion rocketsAdam Crowl
This document discusses the potential use of magnetic sails (mag sails) to decelerate interstellar spacecraft. It analyzes two vehicle configurations - a pure fusion rocket and a hybrid rocket with a mag sail second stage. The mag sail could reduce the required fuel by decelerating the vehicle from cruise speed to 1500 km/s before the final deceleration via fusion. Analysis shows the hybrid design could meet the 100-year mission to Alpha Centauri with an initial mass of 12,300 tonnes, significantly less than the 28,600 tonnes required for a pure fusion vehicle. Further research is needed to determine how to protect large mag sail structures from dust in the interstellar medium.
EAGES Proceedings - K. V. Rozhdestvenskii 1Stephan Aubin
In 2001 Euroavia Toulouse organized a symposium on ground effect. We invited most of the Russian and German actors, and some experts from Holland, UK or France for a week of science around the subject of ekranoplans / flying boats. This was dedicated to students. A book was issued... and now that all copies have been sold for a while I am sharing this on LinkedIn for everyone.
Enjoy.
Stéphan AUBIN
45 investigation paper id 0008 edit septianIAESIJEECS
Most numerical studies on flow over buildings simplify the geometry of the roof and assume that it is flat. This may lead to misrepresentation of the flow as the roof of actual buildings contains some sort of roughness. In this study, the flow over the administrative building of Universiti Tenaga Nasional is investigated for multidirectional flow conditions. The actual topology of the building is gridded and simulated using the steady-state Reynolds-averaged Navier-Stokes equation. Four points at the top of the building are identified and the wind statistics at these designated locations at three different heights are investigated. The optimal location with the highest average wind speed and consistent wind speeds for all wind angles is identified and is earmarked as a potential location to install the wind turbine.
This document discusses the analytical approach to modeling the longitudinal disturbed motion of an ekranoplan (wing-in-ground effect craft). It presents the linearized differential equations describing the craft's horizontal speed, flight altitude, and pitch angle in response to disturbances. Dimensionless forms of the equations are derived using characteristic time scales and coefficients for the aerodynamic forces and moments. Analysis of the characteristic determinant reveals the system responds to disturbances through combinations of the aerodynamic derivatives with respect to pitch angle, altitude, and vertical speed.
This document summarizes a trade study conducted to determine the best design for a deployable drag device to accelerate the orbital decay of upper stage launch vehicles. The trade study compared different device types (drag sails, inflatables, tethers, propulsive), launch vehicles, target orbit altitudes, desired decay times, and packaging constraints. A drag sail design was proposed as the baseline option due to its lower cost and mass efficiency compared to a propulsive option, while still meeting the design requirement of deorbiting within 25 years. A stability analysis was then conducted to determine the optimal drag sail configuration before preliminary component selection and structural analysis.
This document presents an empirical state-space representation of Theodorsen's lift model for airfoils. It develops low-dimensional state-space models that isolate the effects of added-mass forces, quasi-steady forces, and the wake, similar to the original Theodorsen model. An empirical Theodorsen model is constructed from simulation data of a pitching flat plate at low Reynolds number. The resulting state-space models are useful for modeling unsteady aerodynamics and designing flight controllers.
This document discusses atmospheric chemistry models and their use in quantifying atmospheric concentrations and fluxes. Global 3D models divide the atmosphere into grid boxes and use the continuity equation to track species concentrations over time, accounting for transport, chemistry, emissions and deposition. Transport is parameterized using turbulence and convection schemes. Chemistry is solved using operator splitting and implicit methods. Models are evaluated and improved using atmospheric observations from satellites, aircraft and surface sites through data assimilation techniques like inverse modeling. Examples are given of various applications of the GEOS-CHEM global model.
This document discusses different types of climate models and their components and uses. It begins by defining climate models as mathematical representations of the climate system based on physical principles. It then describes four main types of climate models: (1) energy balance models which use simplified equations to model global or regional energy budgets, (2) Earth system models of intermediate complexity which have more complex representations than EBMs but less than GCMs, (3) general circulation models which use 3D grids to model interactions between components at a regional scale, and (4) emulators which use statistical techniques to link climate drivers to impacts. The document also discusses key components of models, their development over time, grid size considerations, and how models are used
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Flow Physics analysis of Three-bucket Helical Savonius rotor at 90 degree twi...BBIT Kolkata
This document analyzes the flow behavior of a helical Savonius rotor using computational fluid dynamics (CFD). It constructs a 3D model of a three-bladed helical Savonius rotor with a 90 degree twist angle. CFD simulations are performed to obtain contours of static pressure and velocity around the rotor blades at different rotor angles. The simulations show that high performance is obtained when the advancing blade is upstream of the airflow at a rotor angle of 90 degrees, and maximum positive static pressure is obtained at a rotor angle of 0 degrees, which affects the positive coefficient of static torque.
Analysis Of Owl-Like Airfoil Aerodynamics At Low Reynolds Number FlowKelly Lipiec
The document analyzes the aerodynamic characteristics of an owl-like airfoil at a low Reynolds number of 23,000 using computational fluid dynamics simulations. It finds that the owl-like airfoil achieves higher lift coefficients and lift-to-drag ratios than the Ishii airfoil, which was designed for high performance at low Reynolds numbers. The owl-like airfoil's round leading edge, flat upper surface, and deeply concaved lower surface contribute to lift enhancement through mechanisms like a suction peak and laminar separation bubble near the leading edge. However, the owl-like airfoil does not achieve its minimum drag coefficient at zero lift, unlike the Ishii airfoil. The document aims to provide insights that can
The document summarizes a numerical study that investigated the effect of distributed trailing edge suction on the aerodynamic performance of a wind turbine airfoil. Computational fluid dynamics simulations were performed on a NACA 63-415 airfoil with and without trailing edge suction at different angles of attack. The results showed that moderate levels of suction (0.5 m/s) improved the airfoil's lift-to-drag ratio by increasing maximum lift and reducing drag. Higher suction velocities (over 1 m/s) decreased aerodynamic performance by increasing drag. The optimum angle of attack was also increased from 4 degrees to 6 degrees with suction. Streamline visualizations indicated that suction effectively removed boundary layer flow
NUMERICAL STUDIES ON THE LIQUID REQUIREMENTS FOR COMPLETE TRANSIENT CHILLDOWN...IAEME Publication
This document presents a numerical study on the liquid requirements for complete transient chilldown of helically coiled transfer lines. Computational fluid dynamics (CFD) modeling was used to determine the quantity of liquid nitrogen required and time taken for complete chilldown of transfer lines with different helix angles (20°, 25°, 30°). It was found that the mass of fluid used and time taken for complete chilldown reduces as the helix angle increases, due to increased centrifugal forces. Validation of the CFD code was also performed against experimental data from literature.
This document describes the design of a bio-inspired flexible wing for flapping-wing micro air vehicles. The researchers experimentally tested the load-deformation characteristics of hawkmoth wings and used this data to design a synthetic flexible wing with matching deformation properties. Finite element analysis was used to model the structural response of the synthetic wing design. An optimization process then matched the deformation profile of the synthetic wing to that of real hawkmoth wings by varying the vein diameters and moduli in the design. The aerodynamic performance of the flexible synthetic wing was then tested and compared to a rigid wing of similar geometry on a robotic flapper.
Seismic Analysis of Reinforced Concrete Shaft Support Water Storage TankIJERA Editor
This document summarizes a research paper that compares the seismic analysis of reinforced concrete shaft-supported water storage tanks according to two Indian codes: IS 1893-1984 and IS 1893-2002 (Part 2). The analysis was conducted for tanks of 500, 750, and 1000 cubic meters in different seismic zones and soil types. Parameters like base shear, base moment, and time history analysis results were compared between one-mass and two-mass tank models. The 2002 code produced higher base shear values, indicating existing tanks may be deficient. Empty tanks had higher base moments than full tanks. Two-mass models provided a more realistic representation of tank response than one-mass models.
EAGES Proceedings - K. V. Rozhdestvenskii 2Stephan Aubin
In 2001 Euroavia Toulouse organized a symposium on ground effect. We invited most of the Russian and German actors, and some experts from Holland, UK or France for a week of science around the subject of ekranoplans / flying boats. This was dedicated to students. A book was issued... and now that all copies have been sold for a while I am sharing this on LinkedIn for everyone.
Enjoy.
Stéphan AUBIN
Glider Advancements in Efficiency: Enhancing Factors Necessary for Ocean-Wide...LiamRamsay
Research Paper written for the Autonomous Underwater Vehicle (AUV) Teledyne Marine Slocum Glider. Paper was published for the MTS/IEEE OCEANS Conference 2015 Washington D.C.
The Optimization of the Generalized Coplanar Impulsive Maneuvers (Two Impulse...paperpublications3
Abstract: The orbit transfer problems using impulsive thrusters have attracted researchers for a long time [3]. One of the objectives in these problems is to find the optimal fuel orbit transfer between two orbits, generally inclined eccentric orbits. The optimal two-impulse orbit transfer problem poses multiple local optima, and classical optimization methods find only local optimum solution. McCue [7] solved the problem of optimal two-impulse orbit transfer using a combination between numerical search and steepest descent optimization procedures. The transfer of satellites in too high orbits as geosynchronous one (geostationary), usually is achieved firstly by launching the satellite in Low Earth Orbit (LEO) (Parking orbit), then in elliptical transfer orbit and finally to the final orbit (Working orbit). The three steps process is known as Hohmann transfer. The Hohmann transfer which involves two circular orbits with different orbital inclinations is known as non‐coplanar Hohmann transfer. If both orbital planes are aligned the Hohmann transfer is known as coplanar what is further considered in this paper. In terms of propellant consumptions the Hohmann transfer is the best known transfer to be applied when transferring between elliptical coplanar orbits. For transfer between elliptical coplanar orbits, the given information usually consists of the altitude of perigee and apogee of the initial and the altitude of perigee and apogee of the final orbits. The velocity to be applied into two orbit points in order to attain the dedicated final orbit is analyzed.
The aim of this paper is compare between three types of coplanar impulsive transfer (two impulses, three impulses and one tangent burn) and conclude about the velocity changes for these types under relation between initial low Earth altitudes and final orbit. For the relation between initial orbit altitudes and final orbit altitude, the velocities to be applied in process of Hohmann transfer are simulated. From respective simulations, the velocity variations on dependence of this relation are derived. And the time of flight is considered too. The problem of spacecraft orbit transfer with minimum fuel consumption is considered, in terms of testing numerical solutions.
Numerical Investigation of Turbulent Flow Around a Stepped Airfoil at High Re...ROSHAN SAH
This presentation describes a mathematical investigation of turbulent flow around a stepped airfoil. It includes the design of stepped airfoil, airfoil theory, governing equation of turbulence modeling and boundary condition. whereas, results and discussion are shown in second presentation on same topic.
Nwtc turb sim workshop september 22 24, 2008- site specific modelsndkelley
1) The document describes several inflow turbulence models available in the TurbSim code developed by NREL, including models based on standard IEC conditions, smooth homogeneous terrain, specific wind farm sites, complex mountainous terrain, and a North American high plains site.
2) Comparisons of simulation results using the IEC, Great Plains, and NWTC models show differences in predicted blade loads, rotor torque, bending moments and tip deflections when applied to the NREL 5 MW reference turbine.
3) In particular, the Great Plains model including a low-level jet produced significantly higher loads and deflections compared to the standard IEC model, demonstrating the importance of using site-specific models.
Calculation of Fluid Dynamic for Wind Flow around Reinforced Concrete WallsIJERA Editor
A study on the flow phenomena around free-standing walls is important in practical building construction. In the present paper a numerical study is conducted for two- dimensional incompressible steady flow around freestanding walls using low-Re k-co turbulence model. The separation regions downstream the wall and on the roof of the leeward were predicted. Finally, results of numerical simulation are presented in the form of velocity vectors, velocity contour, pressure contours and streamlines
Magnetic sail braking vs two-stage fusion rocketsAdam Crowl
This document discusses the potential use of magnetic sails (mag sails) to decelerate interstellar spacecraft. It analyzes two vehicle configurations - a pure fusion rocket and a hybrid rocket with a mag sail second stage. The mag sail could reduce the required fuel by decelerating the vehicle from cruise speed to 1500 km/s before the final deceleration via fusion. Analysis shows the hybrid design could meet the 100-year mission to Alpha Centauri with an initial mass of 12,300 tonnes, significantly less than the 28,600 tonnes required for a pure fusion vehicle. Further research is needed to determine how to protect large mag sail structures from dust in the interstellar medium.
EAGES Proceedings - K. V. Rozhdestvenskii 1Stephan Aubin
In 2001 Euroavia Toulouse organized a symposium on ground effect. We invited most of the Russian and German actors, and some experts from Holland, UK or France for a week of science around the subject of ekranoplans / flying boats. This was dedicated to students. A book was issued... and now that all copies have been sold for a while I am sharing this on LinkedIn for everyone.
Enjoy.
Stéphan AUBIN
45 investigation paper id 0008 edit septianIAESIJEECS
Most numerical studies on flow over buildings simplify the geometry of the roof and assume that it is flat. This may lead to misrepresentation of the flow as the roof of actual buildings contains some sort of roughness. In this study, the flow over the administrative building of Universiti Tenaga Nasional is investigated for multidirectional flow conditions. The actual topology of the building is gridded and simulated using the steady-state Reynolds-averaged Navier-Stokes equation. Four points at the top of the building are identified and the wind statistics at these designated locations at three different heights are investigated. The optimal location with the highest average wind speed and consistent wind speeds for all wind angles is identified and is earmarked as a potential location to install the wind turbine.
This document discusses the analytical approach to modeling the longitudinal disturbed motion of an ekranoplan (wing-in-ground effect craft). It presents the linearized differential equations describing the craft's horizontal speed, flight altitude, and pitch angle in response to disturbances. Dimensionless forms of the equations are derived using characteristic time scales and coefficients for the aerodynamic forces and moments. Analysis of the characteristic determinant reveals the system responds to disturbances through combinations of the aerodynamic derivatives with respect to pitch angle, altitude, and vertical speed.
This document summarizes a trade study conducted to determine the best design for a deployable drag device to accelerate the orbital decay of upper stage launch vehicles. The trade study compared different device types (drag sails, inflatables, tethers, propulsive), launch vehicles, target orbit altitudes, desired decay times, and packaging constraints. A drag sail design was proposed as the baseline option due to its lower cost and mass efficiency compared to a propulsive option, while still meeting the design requirement of deorbiting within 25 years. A stability analysis was then conducted to determine the optimal drag sail configuration before preliminary component selection and structural analysis.
This document presents an empirical state-space representation of Theodorsen's lift model for airfoils. It develops low-dimensional state-space models that isolate the effects of added-mass forces, quasi-steady forces, and the wake, similar to the original Theodorsen model. An empirical Theodorsen model is constructed from simulation data of a pitching flat plate at low Reynolds number. The resulting state-space models are useful for modeling unsteady aerodynamics and designing flight controllers.
This document discusses atmospheric chemistry models and their use in quantifying atmospheric concentrations and fluxes. Global 3D models divide the atmosphere into grid boxes and use the continuity equation to track species concentrations over time, accounting for transport, chemistry, emissions and deposition. Transport is parameterized using turbulence and convection schemes. Chemistry is solved using operator splitting and implicit methods. Models are evaluated and improved using atmospheric observations from satellites, aircraft and surface sites through data assimilation techniques like inverse modeling. Examples are given of various applications of the GEOS-CHEM global model.
This document discusses different types of climate models and their components and uses. It begins by defining climate models as mathematical representations of the climate system based on physical principles. It then describes four main types of climate models: (1) energy balance models which use simplified equations to model global or regional energy budgets, (2) Earth system models of intermediate complexity which have more complex representations than EBMs but less than GCMs, (3) general circulation models which use 3D grids to model interactions between components at a regional scale, and (4) emulators which use statistical techniques to link climate drivers to impacts. The document also discusses key components of models, their development over time, grid size considerations, and how models are used
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Flow Physics analysis of Three-bucket Helical Savonius rotor at 90 degree twi...BBIT Kolkata
This document analyzes the flow behavior of a helical Savonius rotor using computational fluid dynamics (CFD). It constructs a 3D model of a three-bladed helical Savonius rotor with a 90 degree twist angle. CFD simulations are performed to obtain contours of static pressure and velocity around the rotor blades at different rotor angles. The simulations show that high performance is obtained when the advancing blade is upstream of the airflow at a rotor angle of 90 degrees, and maximum positive static pressure is obtained at a rotor angle of 0 degrees, which affects the positive coefficient of static torque.
Analysis Of Owl-Like Airfoil Aerodynamics At Low Reynolds Number FlowKelly Lipiec
The document analyzes the aerodynamic characteristics of an owl-like airfoil at a low Reynolds number of 23,000 using computational fluid dynamics simulations. It finds that the owl-like airfoil achieves higher lift coefficients and lift-to-drag ratios than the Ishii airfoil, which was designed for high performance at low Reynolds numbers. The owl-like airfoil's round leading edge, flat upper surface, and deeply concaved lower surface contribute to lift enhancement through mechanisms like a suction peak and laminar separation bubble near the leading edge. However, the owl-like airfoil does not achieve its minimum drag coefficient at zero lift, unlike the Ishii airfoil. The document aims to provide insights that can
The document summarizes a numerical study that investigated the effect of distributed trailing edge suction on the aerodynamic performance of a wind turbine airfoil. Computational fluid dynamics simulations were performed on a NACA 63-415 airfoil with and without trailing edge suction at different angles of attack. The results showed that moderate levels of suction (0.5 m/s) improved the airfoil's lift-to-drag ratio by increasing maximum lift and reducing drag. Higher suction velocities (over 1 m/s) decreased aerodynamic performance by increasing drag. The optimum angle of attack was also increased from 4 degrees to 6 degrees with suction. Streamline visualizations indicated that suction effectively removed boundary layer flow
NUMERICAL STUDIES ON THE LIQUID REQUIREMENTS FOR COMPLETE TRANSIENT CHILLDOWN...IAEME Publication
This document presents a numerical study on the liquid requirements for complete transient chilldown of helically coiled transfer lines. Computational fluid dynamics (CFD) modeling was used to determine the quantity of liquid nitrogen required and time taken for complete chilldown of transfer lines with different helix angles (20°, 25°, 30°). It was found that the mass of fluid used and time taken for complete chilldown reduces as the helix angle increases, due to increased centrifugal forces. Validation of the CFD code was also performed against experimental data from literature.
retrieving the dead or soon to be terminated satellites from its orbit by providing a specially made carbon fiber heat shield which will be preinstalled the satellites
IRJET-To Investigate the effect of Spinner Geometry on COP of Vortex Tube Ref...IRJET Journal
This document summarizes a research paper that investigates how changing the geometry of the spinner inside a vortex tube affects its coefficient of performance (COP) for refrigeration. The paper describes how a vortex tube works by separating compressed air into hot and cold streams. It then discusses changing the angle of the spinner notches within the vortex tube from 25 to 45 degrees and using computational fluid dynamics (CFD) software to analyze how this affects temperatures and COP. The document reviews previous literature on vortex tube experiments and analysis, and describes the methodology of using CAD software to model different spinner angles and CFD to simulate flow, temperature, and pressure within the vortex tube.
Analysis of dual bell rocket nozzle using computational fluid dynamicseSAT Journals
Abstract Concept of Altitude adaptive rocket nozzles recently received greater importance and interest in the space explorations and other such applications in space and rocket technology. The operations reliability of rocket launcher and the earth to orbit rocket launch are the crucial for the space transportation in the future. The performance of the engine components such as the power plant and the thrust delivery of the engine such as nozzles are in renovation for the greater performance and applicability for complex space applications. In the recent progress of the combustion expansion system the rocket nozzles are greatly revised from both application and design perspectives. One of such development is the dual bell nozzle. The publications indicate that the research on the concept of dual bell nozzle is tardy and there is no much progress from the inception of the idea. The specific application purpose designs are tested experimentally and implemented but the large scale development can only be possible if the generalized design parameters can be suggested. In the present paper one of such nozzle is selected and studied using computational fluid dynamics (CFD) and the results are synthesized for bench marking the general approach to study the Dual Bell nozzles. The result shows the variation in the Mach number, pressure, temperature distribution and turbulence intensity. Keywords: Altitude adaptation, Dual bell nozzle, Nozzle pressure ratio, Over-expansion factor.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
The document describes a numerical study of heat transfer in a heat collector element (HCE) of a solar parabolic trough collector. A 3D conjugate heat transfer analysis was performed using ANSYS Fluent to model conduction, convection and radiation within the HCE, which consists of a metallic tube surrounded by an evacuated glass shield. Seasonal and daily variations of solar radiation were considered for conditions in Pune, India. The analysis found that fluid pressure drop and heating were higher during summer noon compared to other times, with fluid temperature increasing up to 4 times from morning to noon in winter.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
This document summarizes a CFD simulation of airfoil flow. It describes setting up the fluid domain as a 2D model of an NACA 2412 airfoil with a chord length of 1m. Various turbulence models are evaluated including SST k-omega, RNG k-epsilon, and Spalart-Allmaras. Flow is simulated as both incompressible and compressible. Results show the lift and drag coefficients at different angles of attack. The NACA 2412 airfoil is found to have greater maximum performance than the NACA 0012. Incompressible flow results are validated against experimental data.
This document summarizes a numerical simulation of ventilation systems in the archaeological tomb of Horemheb in the Valley of the Kings in Luxor, Egypt. The study used computational fluid dynamics to model airflow patterns, temperature, and relative humidity within the tomb under different ventilation system designs and numbers of visitors. The results showed that mechanical ventilation helped maintain temperatures around 305K and relative humidity below 70% within recommended comfort levels. Peak humidity occurred in winter months, so limiting visits then was suggested. Air velocity was kept below 0.12 m/s within the tomb to prevent wall painting erosion.
On The Form Factor Prediction Of A Displacement Type Vessel: JBC CaseIsmail Topal
This document summarizes a study on predicting the form factor of a displacement type vessel (JBC hull) using computational fluid dynamics (CFD). Single-phase CFD simulations were performed for the JBC hull at various velocities within the Prohaska range. The form factor, which represents the ratio of viscous pressure force to frictional force, was calculated from the simulations and found to depend on Reynolds number, contrary to Prohaska's theory of independence. Frictional force results matched well with empirical ITTC formulas. The study aims to further investigate scale effects on form factor prediction.
This document summarizes a study on predicting the form factor of a ship hull through computational fluid dynamics simulations. Researchers conducted single-phase CFD simulations of flow around a Japanese Bulk Carrier hull model at various velocities within the Prohaska range. They evaluated mesh dependency, calculated friction coefficients compared to empirical data, and analyzed the effect of Reynolds number on predicted form factors. The study found that the form factor depends on ship velocity, contrary to Prohaska's theory, and suggests further investigation of scale effects on form factor predictions.
Effect of Geometry on Variation of Heat Flux and Drag for Launch Vehicle -- Z...Abhishek Jain
Above Research Paper can be downloaded from www.zeusnumerix.com
The research paper aims at studying the variation of the geometry of the launch vehicle nose and its effect on heat flux. CFDExpert software is first validated on NASA's hyperballistic model and then used on proposed geometries. Various nose radius and blending shapes are studied for effect on drag and heat flux. Cone ogive shape is found to decrease heat flux with an insignificant increase in drag. Authors Abhishek Jain (Zeus Numerix), Rohan Kedar and Prof V Kalamkar (SPCOE).
This document summarizes a computational fluid dynamics (CFD) study comparing the aerodynamic performance of a bio-inspired corrugated dragonfly wing aerofoil to conventional flat plate and NACA airfoils. CFD simulations were conducted at Reynolds numbers of 20,000-100,000 and angles of attack from 0-25 degrees. Results showed that the corrugated aerofoil had improved aerodynamic performance over the other airfoils, with a higher stall angle and increased lift. This is due to the corrugations reducing flow separation. The corrugated aerofoil design could potentially be incorporated into micro air vehicles (MAVs) to enhance their aerodynamic performance.
This document summarizes a study on the soil-structure interaction of a cylindrical tank with variable wall thickness under thermal gradient conditions. The study uses two subsoil models - an elastic half-space model and a Winkler spring model - to describe the behavior of the tank structure. Analytical methods are presented to analyze the hydrostatic and thermal loading of the tank for each subsoil model. For the hydrostatic loading case, the elastic half-space model shows decreases in radial displacement and changes in bending moment distribution compared to the Winkler model. However, for thermal gradient loading the solutions between the two models do not differ significantly.
CFD Analysis of a Heat Collector Element in a Solar Parabolic Trough Collector iMentor Education
A numerical study of the performance of a solar Parabolic Trough Collector (PTC) has been done focusing on its receiver. The receiver consisting of a glass-shield enclosing a Heat Collector Element (HCE) with vacuum in the annular space has been subjected to seasonal and diurnal variations of solar radiation along with the
concentrated heat flux reflected from the parabolic trough mirror for conditions at Pune, India. The HCE is modeled as a metallic tube with thermic fluid Therminol-VP1TM flowing through it at low Reynolds number under thermally developing conditions with highly temperature dependent properties. The highly asymmetric
nature of the physics for thermal and turbulent flow conditions make it imperative to consider a complete three dimensional domain for the conjugate heat transfer analysis. The conduction, convection and radiation heat transfer effects have been modeled with radiation restricted within the annular region using the S2S radiation
model. The solar fluxes have been modeled using the Solar Load Model also accounting for the shadowing effects for semi-transparent and opaque surfaces. The pressure drop in the thermic fluid flow is comparatively uniform throughout the day during winter conditions while the fluid gets heated up 4 times more at noon
compared to morning. The summer conditions exhibit a 2.5 times higher pressure drop at noon compared to the morning conditions. The comprehensive analysis is performed using the finite volume based CFD code of ANSYS FLUENT 12.1 and verifies the huge potential that PTC holds for high temperature applications in
concentrated solar power plants.
This document summarizes the research investigating the effect of longitudinal atmospheric turbulence on the dynamics of an airfoil with a structural nonlinearity in pitch. Three different regions of dynamic behavior are observed when the airfoil is excited by longitudinal turbulence, compared to two regions for the nonexcited case. A new region exists where the airfoil response is concentrated about the equilibrium position, attributed to the parametric nature of the turbulence excitation. Utter occurs at a lower velocity and limit cycle oscillations occur at a higher velocity for the excited case versus the nonexcited case. The airfoil and aerodynamic models used in the numerical simulations are described.
The document describes the development of a computational model to simulate the transient heat transfer of a heated jet impinging on a ground plane. The model uses heat flux output from a CFD model of the jet as the thermal boundary condition for the ground plane. Simulations were run for ground planes of two thicknesses made of aluminum. The results showed similar temperature distributions to experimental data. The model predicted faster temperature rises than experiments, requiring further calibration. The thicker plate reached outer temperatures allowing heat transfer back to the flow within 20 seconds, while the thinner plate saw inner temperatures rise quickly and outer temperatures lag. The model begins to provide insight into heat transfer rates and temperatures on a naval ship deck during aircraft landing or takeoff.
The UCLA Rocket Project has continued developing its custom hybrid rocket engine called HyPE for the 6th Intercollegiate Rocket Engineering Competition. The HyPE uses paraffin wax and aluminum powder fuel with nitrous oxide oxidizer, and is capable of propelling a 10 pound payload to 25,000 feet. Students designed and built a carbon fiber airframe, recovery system, avionics, and ground support equipment. Aerodynamic analysis was performed to optimize the rocket's drag, and a 4.5:1 LD Haack nose cone was selected to reduce wave drag at supersonic speeds. The project involves over 30 students and aims to compete in and win the advanced category of IREC.
Similar to IJERD (www.ijerd.com) International Journal of Engineering Research and Development (20)
A Novel Method for Prevention of Bandwidth Distributed Denial of Service AttacksIJERD Editor
Distributed Denial of Service (DDoS) Attacks became a massive threat to the Internet. Traditional
Architecture of internet is vulnerable to the attacks like DDoS. Attacker primarily acquire his army of Zombies,
then that army will be instructed by the Attacker that when to start an attack and on whom the attack should be
done. In this paper, different techniques which are used to perform DDoS Attacks, Tools that were used to
perform Attacks and Countermeasures in order to detect the attackers and eliminate the Bandwidth Distributed
Denial of Service attacks (B-DDoS) are reviewed. DDoS Attacks were done by using various Flooding
techniques which are used in DDoS attack.
The main purpose of this paper is to design an architecture which can reduce the Bandwidth
Distributed Denial of service Attack and make the victim site or server available for the normal users by
eliminating the zombie machines. Our Primary focus of this paper is to dispute how normal machines are
turning into zombies (Bots), how attack is been initiated, DDoS attack procedure and how an organization can
save their server from being a DDoS victim. In order to present this we implemented a simulated environment
with Cisco switches, Routers, Firewall, some virtual machines and some Attack tools to display a real DDoS
attack. By using Time scheduling, Resource Limiting, System log, Access Control List and some Modular
policy Framework we stopped the attack and identified the Attacker (Bot) machines
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
Influence of tensile behaviour of slab on the structural Behaviour of shear c...IJERD Editor
-A composite beam is composed of a steel beam and a slab connected by means of shear connectors
like studs installed on the top flange of the steel beam to form a structure behaving monolithically. This study
analyzes the effects of the tensile behavior of the slab on the structural behavior of the shear connection like slip
stiffness and maximum shear force in composite beams subjected to hogging moment. The results show that the
shear studs located in the crack-concentration zones due to large hogging moments sustain significantly smaller
shear force and slip stiffness than the other zones. Moreover, the reduction of the slip stiffness in the shear
connection appears also to be closely related to the change in the tensile strain of rebar according to the increase
of the load. Further experimental and analytical studies shall be conducted considering variables such as the
reinforcement ratio and the arrangement of shear connectors to achieve efficient design of the shear connection
in composite beams subjected to hogging moment.
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Reducing Corrosion Rate by Welding DesignIJERD Editor
This document summarizes a study on reducing corrosion rates in steel through welding design. The researchers tested different welding groove designs (X, V, 1/2X, 1/2V) and preheating temperatures (400°C, 500°C, 600°C) on ferritic malleable iron samples. Testing found that X and V groove designs with 500°C and 600°C preheating had corrosion rates of 0.5-0.69% weight loss after 14 days, compared to 0.57-0.76% for 400°C preheating. Higher preheating reduced residual stresses which decreased corrosion. Residual stresses were 1.7 MPa for optimal X groove and 600°C
Router 1X3 – RTL Design and VerificationIJERD Editor
Routing is the process of moving a packet of data from source to destination and enables messages
to pass from one computer to another and eventually reach the target machine. A router is a networking device
that forwards data packets between computer networks. It is connected to two or more data lines from different
networks (as opposed to a network switch, which connects data lines from one single network). This paper,
mainly emphasizes upon the study of router device, it‟s top level architecture, and how various sub-modules of
router i.e. Register, FIFO, FSM and Synchronizer are synthesized, and simulated and finally connected to its top
module.
Active Power Exchange in Distributed Power-Flow Controller (DPFC) At Third Ha...IJERD Editor
This paper presents a component within the flexible ac-transmission system (FACTS) family, called
distributed power-flow controller (DPFC). The DPFC is derived from the unified power-flow controller (UPFC)
with an eliminated common dc link. The DPFC has the same control capabilities as the UPFC, which comprise
the adjustment of the line impedance, the transmission angle, and the bus voltage. The active power exchange
between the shunt and series converters, which is through the common dc link in the UPFC, is now through the
transmission lines at the third-harmonic frequency. DPFC multiple small-size single-phase converters which
reduces the cost of equipment, no voltage isolation between phases, increases redundancy and there by
reliability increases. The principle and analysis of the DPFC are presented in this paper and the corresponding
simulation results that are carried out on a scaled prototype are also shown.
Mitigation of Voltage Sag/Swell with Fuzzy Control Reduced Rating DVRIJERD Editor
Power quality has been an issue that is becoming increasingly pivotal in industrial electricity
consumers point of view in recent times. Modern industries employ Sensitive power electronic equipments,
control devices and non-linear loads as part of automated processes to increase energy efficiency and
productivity. Voltage disturbances are the most common power quality problem due to this the use of a large
numbers of sophisticated and sensitive electronic equipment in industrial systems is increased. This paper
discusses the design and simulation of dynamic voltage restorer for improvement of power quality and
reduce the harmonics distortion of sensitive loads. Power quality problem is occurring at non-standard
voltage, current and frequency. Electronic devices are very sensitive loads. In power system voltage sag,
swell, flicker and harmonics are some of the problem to the sensitive load. The compensation capability
of a DVR depends primarily on the maximum voltage injection ability and the amount of stored
energy available within the restorer. This device is connected in series with the distribution feeder at
medium voltage. A fuzzy logic control is used to produce the gate pulses for control circuit of DVR and the
circuit is simulated by using MATLAB/SIMULINK software.
Study on the Fused Deposition Modelling In Additive ManufacturingIJERD Editor
Additive manufacturing process, also popularly known as 3-D printing, is a process where a product
is created in a succession of layers. It is based on a novel materials incremental manufacturing philosophy.
Unlike conventional manufacturing processes where material is removed from a given work price to derive the
final shape of a product, 3-D printing develops the product from scratch thus obviating the necessity to cut away
materials. This prevents wastage of raw materials. Commonly used raw materials for the process are ABS
plastic, PLA and nylon. Recently the use of gold, bronze and wood has also been implemented. The complexity
factor of this process is 0% as in any object of any shape and size can be manufactured.
Spyware triggering system by particular string valueIJERD Editor
This computer programme can be used for good and bad purpose in hacking or in any general
purpose. We can say it is next step for hacking techniques such as keylogger and spyware. Once in this system if
user or hacker store particular string as a input after that software continually compare typing activity of user
with that stored string and if it is match then launch spyware programme.
A Blind Steganalysis on JPEG Gray Level Image Based on Statistical Features a...IJERD Editor
This paper presents a blind steganalysis technique to effectively attack the JPEG steganographic
schemes i.e. Jsteg, F5, Outguess and DWT Based. The proposed method exploits the correlations between
block-DCTcoefficients from intra-block and inter-block relation and the statistical moments of characteristic
functions of the test image is selected as features. The features are extracted from the BDCT JPEG 2-array.
Support Vector Machine with cross-validation is implemented for the classification.The proposed scheme gives
improved outcome in attacking.
Secure Image Transmission for Cloud Storage System Using Hybrid SchemeIJERD Editor
- Data over the cloud is transferred or transmitted between servers and users. Privacy of that
data is very important as it belongs to personal information. If data get hacked by the hacker, can be
used to defame a person’s social data. Sometimes delay are held during data transmission. i.e. Mobile
communication, bandwidth is low. Hence compression algorithms are proposed for fast and efficient
transmission, encryption is used for security purposes and blurring is used by providing additional
layers of security. These algorithms are hybridized for having a robust and efficient security and
transmission over cloud storage system.
Application of Buckley-Leverett Equation in Modeling the Radius of Invasion i...IJERD Editor
A thorough review of existing literature indicates that the Buckley-Leverett equation only analyzes
waterflood practices directly without any adjustments on real reservoir scenarios. By doing so, quite a number
of errors are introduced into these analyses. Also, for most waterflood scenarios, a radial investigation is more
appropriate than a simplified linear system. This study investigates the adoption of the Buckley-Leverett
equation to estimate the radius invasion of the displacing fluid during waterflooding. The model is also adopted
for a Microbial flood and a comparative analysis is conducted for both waterflooding and microbial flooding.
Results shown from the analysis doesn’t only records a success in determining the radial distance of the leading
edge of water during the flooding process, but also gives a clearer understanding of the applicability of
microbes to enhance oil production through in-situ production of bio-products like bio surfactans, biogenic
gases, bio acids etc.
Gesture Gaming on the World Wide Web Using an Ordinary Web CameraIJERD Editor
- Gesture gaming is a method by which users having a laptop/pc/x-box play games using natural or
bodily gestures. This paper presents a way of playing free flash games on the internet using an ordinary webcam
with the help of open source technologies. Emphasis in human activity recognition is given on the pose
estimation and the consistency in the pose of the player. These are estimated with the help of an ordinary web
camera having different resolutions from VGA to 20mps. Our work involved giving a 10 second documentary to
the user on how to play a particular game using gestures and what are the various kinds of gestures that can be
performed in front of the system. The initial inputs of the RGB values for the gesture component is obtained by
instructing the user to place his component in a red box in about 10 seconds after the short documentary before
the game is finished. Later the system opens the concerned game on the internet on popular flash game sites like
miniclip, games arcade, GameStop etc and loads the game clicking at various places and brings the state to a
place where the user is to perform only gestures to start playing the game. At any point of time the user can call
off the game by hitting the esc key and the program will release all of the controls and return to the desktop. It
was noted that the results obtained using an ordinary webcam matched that of the Kinect and the users could
relive the gaming experience of the free flash games on the net. Therefore effective in game advertising could
also be achieved thus resulting in a disruptive growth to the advertising firms.
Hardware Analysis of Resonant Frequency Converter Using Isolated Circuits And...IJERD Editor
-LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region[5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits.
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...IJERD Editor
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits. The supported simulation
is done through PSIM 6.0 software tool
Amateurs Radio operator, also known as HAM communicates with other HAMs through Radio
waves. Wireless communication in which Moon is used as natural satellite is called Moon-bounce or EME
(Earth -Moon-Earth) technique. Long distance communication (DXing) using Very High Frequency (VHF)
operated amateur HAM radio was difficult. Even with the modest setup having good transceiver, power
amplifier and high gain antenna with high directivity, VHF DXing is possible. Generally 2X11 YAGI antenna
along with rotor to set horizontal and vertical angle is used. Moon tracking software gives exact location,
visibility of Moon at both the stations and other vital data to acquire real time position of moon.
“MS-Extractor: An Innovative Approach to Extract Microsatellites on „Y‟ Chrom...IJERD Editor
Simple Sequence Repeats (SSR), also known as Microsatellites, have been extensively used as
molecular markers due to their abundance and high degree of polymorphism. The nucleotide sequences of
polymorphic forms of the same gene should be 99.9% identical. So, Microsatellites extraction from the Gene is
crucial. However, Microsatellites repeat count is compared, if they differ largely, he has some disorder. The Y
chromosome likely contains 50 to 60 genes that provide instructions for making proteins. Because only males
have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and
development. Several Microsatellite Extractors exist and they fail to extract microsatellites on large data sets of
giga bytes and tera bytes in size. The proposed tool “MS-Extractor: An Innovative Approach to extract
Microsatellites on „Y‟ Chromosome” can extract both Perfect as well as Imperfect Microsatellites from large
data sets of human genome „Y‟. The proposed system uses string matching with sliding window approach to
locate Microsatellites and extracts them.
Importance of Measurements in Smart GridIJERD Editor
- The need to get reliable supply, independence from fossil fuels, and capability to provide clean
energy at a fixed and lower cost, the existing power grid structure is transforming into Smart Grid. The
development of a smart energy distribution grid is a current goal of many nations. A Smart Grid should have
new capabilities such as self-healing, high reliability, energy management, and real-time pricing. This new era
of smart future grid will lead to major changes in existing technologies at generation, transmission and
distribution levels. The incorporation of renewable energy resources and distribution generators in the existing
grid will increase the complexity, optimization problems and instability of the system. This will lead to a
paradigm shift in the instrumentation and control requirements for Smart Grids for high quality, stable and
reliable electricity supply of power. The monitoring of the grid system state and stability relies on the
availability of reliable measurement of data. In this paper the measurement areas that highlight new
measurement challenges, development of the Smart Meters and the critical parameters of electric energy to be
monitored for improving the reliability of power systems has been discussed.
Study of Macro level Properties of SCC using GGBS and Lime stone powderIJERD Editor
The document summarizes a study on the use of ground granulated blast furnace slag (GGBS) and limestone powder to replace cement in self-compacting concrete (SCC). Tests were conducted on SCC mixes with 0-50% replacement of cement with GGBS and 0-20% replacement with limestone powder. The results showed that replacing 30% of cement with GGBS and 15% with limestone powder produced SCC with the highest compressive strength of 46MPa, meeting fresh property requirements. The study concluded that this ternary blend of cement, GGBS and limestone powder can improve SCC properties while reducing costs.
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
Get an inside look at the latest Neo4j innovations that enable relationship-driven intelligence at scale. Learn more about the newest cloud integrations and product enhancements that make Neo4j an essential choice for developers building apps with interconnected data and generative AI.
Let's Integrate MuleSoft RPA, COMPOSER, APM with AWS IDP along with Slackshyamraj55
Discover the seamless integration of RPA (Robotic Process Automation), COMPOSER, and APM with AWS IDP enhanced with Slack notifications. Explore how these technologies converge to streamline workflows, optimize performance, and ensure secure access, all while leveraging the power of AWS IDP and real-time communication via Slack notifications.
How to Get CNIC Information System with Paksim Ga.pptxdanishmna97
Pakdata Cf is a groundbreaking system designed to streamline and facilitate access to CNIC information. This innovative platform leverages advanced technology to provide users with efficient and secure access to their CNIC details.
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
Dr. Sean Tan, Head of Data Science, Changi Airport Group
Discover how Changi Airport Group (CAG) leverages graph technologies and generative AI to revolutionize their search capabilities. This session delves into the unique search needs of CAG’s diverse passengers and customers, showcasing how graph data structures enhance the accuracy and relevance of AI-generated search results, mitigating the risk of “hallucinations” and improving the overall customer journey.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Securing your Kubernetes cluster_ a step-by-step guide to success !KatiaHIMEUR1
Today, after several years of existence, an extremely active community and an ultra-dynamic ecosystem, Kubernetes has established itself as the de facto standard in container orchestration. Thanks to a wide range of managed services, it has never been so easy to set up a ready-to-use Kubernetes cluster.
However, this ease of use means that the subject of security in Kubernetes is often left for later, or even neglected. This exposes companies to significant risks.
In this talk, I'll show you step-by-step how to secure your Kubernetes cluster for greater peace of mind and reliability.
Generative AI Deep Dive: Advancing from Proof of Concept to ProductionAggregage
Join Maher Hanafi, VP of Engineering at Betterworks, in this new session where he'll share a practical framework to transform Gen AI prototypes into impactful products! He'll delve into the complexities of data collection and management, model selection and optimization, and ensuring security, scalability, and responsible use.
A tale of scale & speed: How the US Navy is enabling software delivery from l...sonjaschweigert1
Rapid and secure feature delivery is a goal across every application team and every branch of the DoD. The Navy’s DevSecOps platform, Party Barge, has achieved:
- Reduction in onboarding time from 5 weeks to 1 day
- Improved developer experience and productivity through actionable findings and reduction of false positives
- Maintenance of superior security standards and inherent policy enforcement with Authorization to Operate (ATO)
Development teams can ship efficiently and ensure applications are cyber ready for Navy Authorizing Officials (AOs). In this webinar, Sigma Defense and Anchore will give attendees a look behind the scenes and demo secure pipeline automation and security artifacts that speed up application ATO and time to production.
We will cover:
- How to remove silos in DevSecOps
- How to build efficient development pipeline roles and component templates
- How to deliver security artifacts that matter for ATO’s (SBOMs, vulnerability reports, and policy evidence)
- How to streamline operations with automated policy checks on container images
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
Enchancing adoption of Open Source Libraries. A case study on Albumentations.AIVladimir Iglovikov, Ph.D.
Presented by Vladimir Iglovikov:
- https://www.linkedin.com/in/iglovikov/
- https://x.com/viglovikov
- https://www.instagram.com/ternaus/
This presentation delves into the journey of Albumentations.ai, a highly successful open-source library for data augmentation.
Created out of a necessity for superior performance in Kaggle competitions, Albumentations has grown to become a widely used tool among data scientists and machine learning practitioners.
This case study covers various aspects, including:
People: The contributors and community that have supported Albumentations.
Metrics: The success indicators such as downloads, daily active users, GitHub stars, and financial contributions.
Challenges: The hurdles in monetizing open-source projects and measuring user engagement.
Development Practices: Best practices for creating, maintaining, and scaling open-source libraries, including code hygiene, CI/CD, and fast iteration.
Community Building: Strategies for making adoption easy, iterating quickly, and fostering a vibrant, engaged community.
Marketing: Both online and offline marketing tactics, focusing on real, impactful interactions and collaborations.
Mental Health: Maintaining balance and not feeling pressured by user demands.
Key insights include the importance of automation, making the adoption process seamless, and leveraging offline interactions for marketing. The presentation also emphasizes the need for continuous small improvements and building a friendly, inclusive community that contributes to the project's growth.
Vladimir Iglovikov brings his extensive experience as a Kaggle Grandmaster, ex-Staff ML Engineer at Lyft, sharing valuable lessons and practical advice for anyone looking to enhance the adoption of their open-source projects.
Explore more about Albumentations and join the community at:
GitHub: https://github.com/albumentations-team/albumentations
Website: https://albumentations.ai/
LinkedIn: https://www.linkedin.com/company/100504475
Twitter: https://x.com/albumentations
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
“An Outlook of the Ongoing and Future Relationship between Blockchain Technologies and Process-aware Information Systems.” Invited talk at the joint workshop on Blockchain for Information Systems (BC4IS) and Blockchain for Trusted Data Sharing (B4TDS), co-located with with the 36th International Conference on Advanced Information Systems Engineering (CAiSE), 3 June 2024, Limassol, Cyprus.
20 Comprehensive Checklist of Designing and Developing a WebsitePixlogix Infotech
Dive into the world of Website Designing and Developing with Pixlogix! Looking to create a stunning online presence? Look no further! Our comprehensive checklist covers everything you need to know to craft a website that stands out. From user-friendly design to seamless functionality, we've got you covered. Don't miss out on this invaluable resource! Check out our checklist now at Pixlogix and start your journey towards a captivating online presence today.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
Leonard Jayamohan, Partner & Generative AI Lead, Deloitte
This keynote will reveal how Deloitte leverages Neo4j’s graph power for groundbreaking digital twin solutions, achieving a staggering 100x performance boost. Discover the essential role knowledge graphs play in successful generative AI implementations. Plus, get an exclusive look at an innovative Neo4j + Generative AI solution Deloitte is developing in-house.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...
IJERD (www.ijerd.com) International Journal of Engineering Research and Development
1. International Journal of Engineering Research and Development
eISSN : 2278-067X, pISSN : 2278-800X, www.ijerd.com
Volume 2, Issue 4 (July 2012), PP. 29-34
Flow Simulation over Re-Entry Bodies at Supersonic &
Hypersonic Speeds
Shiva Prasad U.1, Srinivas G.2
1,2
Manipal Institute of Technology, Manipal University, Manipal, Karnataka, INDIA.
Abstract— In the present paper, flow simulations are carried on two design configurations of re-entry vehicles, FIRE II
and OREX using commercial flow solvers. The purpose of the paper is to present the effect of flight attitude upon the
aerodynamic characteristics of an Apollo shaped re-entry capsule. This paper exemplifies the importance of the
aerodynamic forces effect on the motion of re-entry vehicle, especially at such high speeds, that even a slight change in
angle of attack can severely alter the activity of the re-entry capsule including the shock wave which plays such a big
factor in the fate of the craft. The study demonstrates the importance of understanding the effects of shock waves and
illustrates how small change in flight attitude can alter the resulting aerodynamic forces on the capsule. Finally, any
minor alteration to the shape of the craft will be discussed which have great implications on the dynamics of craft.
Keywords— Capsules, CFD, Mach number, Re-Entry, Shock waves.
I. INTRODUCTION
In this paper, the type of re-entry vehicle considered is re-entry capsule, which re-enters earth’s atmosphere from
an orbit. The primary design consideration of re-entry capsules requires large spherical nose radius of their fore body that
gives high aerodynamic drag and a short body length for reducing the total structural weight and the ballistic coefficient [1].
In order to know more about the planets and the natural satellites present in our Solar system, there is a need for us to enter
an orbit around that planet or satellite and observe them. For better understanding, we might even have to send rovers onto
the surface of the planet or satellite to conduct experiments, and if possible, bring them back to Earth. For this to happen, the
space probe must pass through their atmosphere, reach the surface intact, conduct experiments there, travel back to Earth and
perform another re-entry phase in order to reach Earth’s surface with the data collected. For this to happen, the re-entry
vehicle must be designed accordingly and analysed using experimental and numerical methods which provide valuable
knowledge for future spacecrafts such as crew exploration vehicle, especially with the recent call to move back to the old
Apollo shaped re-entry vehicles rather than the usage of space shuttles. Hence, the paper explores the analysis on re-entry
capsules.
II. OBJECTIVE
The re-entry vehicle considered is a low Ballistic Coefficient (BC) re-entry capsule. In the present work, CFD
analysis is carried on two design configurations of re-entry vehicles, FIRE II and OREX using fluent software. A study is
taken up on the flow field features around the re-entry vehicle at supersonic and hypersonic speeds.
III. RE-ENTRY CAPSULES
Aeroshells are designed to deliver payloads safely through a planetary atmosphere, protecting the payload from the
high aerodynamic heating and loads encountered during EDL (Entry Descent, Landing). An aeroshell generally consists of a
forebody which faces the flow and a backshell which completes the encapsulation of the payload. The specific shape of a
particular aeroshell is driven by EDL performance requirements and thermal/structural limitations. Here in fig. 1 two
different aeroshell shapes are presented.
Fig.1 Different Aeroshell Shapes [8,9].
A. Design Configurations
Ballistic probes have the advantage that they do not require guidance and control precautions [4]. Therefore these
concepts are less costly than lifting ones but they need low ballistic factors for direct entry. Low ballistic factor means large
29
2. Flow Simulation over Re-Entry Bodies at Supersonic & Hypersonic Speeds
reference area, high drag coefficient and low mass. Normally, for all known missions, an appropriate mass reduction is
critical.
Fig.2 Geometrical details of FIRE II and OREX Re-Entry bodies [2, 3].
Project FIRE was an Apollo era experiment to measure the radiative and convective heating during atmospheric
entry at lunar return speeds. The Fire II reentry vehicle consisted of a multi-layer configuration made up of three phenolic-
asbestos heat shields sandwiched between beryllium calorimeters. Fig. 2 is a schematic of the vehicle showing the
configurations. The 66° included angle conical afterbody section was constructed of a fiberglass shell supporting a layer of
phenolic-asbestos heat protection material. A thin surface coating of silicon elastomer was added for pre-launch moisture
protection. The conical frustum portion of the afterbody was instrumented with a symmetrical array of 12 gold calorimeters,
distributed at three circumferential locations and four stations on the frustum. The calorimeters and their associated heat
shields were designed to be ejected after the onset of melting, yielding three separate data-gathering periods.
The OREX geometry is depicted in Fig. 2 with the detailed dimension. The fore-body shape consists of RN = 1.35
m, a half-angle cone of RN = 50 deg, D = 3.4 m, L = 1.508 m, and RC = 0.01 m. The OREX geometry incorporates a rear
cover with a small backward facing step at the junction between back cover and heat shield. The aft body is having α B = 15
deg, half-angle cone relative to the plane of symmetry.
There is no doubt that the aerothermodynamics of the APOLLO capsule are one of the best known. Due to the
large number of flights in the 1960s and 1970s either in Earth orbit or of Lunar return, the free-flight data base is remarkable
[4]. The OREX free-flight experiment gives the possibility to study how intensive is the influence of physical phenomena
along the re-entry trajectory [5].
IV. BOUNDARY CONDITIONS
A. Initial Conditions
The free-flight experiment gives the possibility to study how intensive is the influence of physical phenomena
along the re-entry trajectory on the wall heat flux [5]. In [6], viscous shock layer (VSL) and Navier–Stokes (NS) solutions
were generated for selected trajectory points with various degrees of modelization, where at the wall, a temperature
distribution was prescribed. The general trend is that for less than 100 km altitudes the computations with slip conditions
give the more realistic answer [7].
The important factor affecting convergence of the two problems is the desired boundary conditions. Both the
capsules were examined in this paper occurred during free stream conditions[10] at 76 km and 85 km flight conditions are
given in Table I the subscript represents free-stream value.
Table I: Initial boundary conditions
M∞ P∞, Pa T∞, K
3.0 2073 224
5.0 1238 232
B. Modeling Turbulence
Turbulent flows are characterized by fluctuating velocity fields. These fluctuations mix transported quantities such
as momentum, energy, and species concentration, and cause the transported quantities to fluctuate as well. Since these
fluctuations can be of small scale and high frequency, they are too computationally expensive to simulate directly in
practical engineering calculations. Instead, the instantaneous (exact) governing equations can be time-averaged, ensemble-
averaged, or otherwise manipulated to remove the small scales, resulting in a modified set of equations that are
computationally less expensive to solve. However, the modified equations contain additional unknown variables, and
turbulence models are needed to determine these variables in terms of known quantities.
30
3. Flow Simulation over Re-Entry Bodies at Supersonic & Hypersonic Speeds
The k-ε turbulence model is a two-equation model in which the solution of two separate transport equations allows
the turbulent velocity and length scales to be independently determined. The model has become the workhorse of practical
engineering flow calculations in the time since it was proposed by Launder and Spalding. Robustness, economy, and
reasonable accuracy for a wide range of turbulent flows explain its popularity in industrial flow and heat transfer simulations.
The standard k-ε model is a semi-empirical model based on model transport equations for the turbulence kinetic energy (k)
and its dissipation rate (ε). The model transport equation for k is derived from the exact equation, while the model transport
equation for ε was obtained using physical reasoning and bears little resemblance to its mathematically exact
counterpart. For the reentry flight simulations, the axisymmetric turbulent predictions with the k–ε models are in reasonable
agreement with the flight measurements [11]. The k-ε model is used in the present paper to validate the turbulent flow over
reentry bodies.
C. Grid Sensitivity
One possibility for the poor agreement between the computation and experiment is grid resolution. In order to
examine this effect, grid refinement studies were conducted covering a range of mach numbers 3-5 based on geometry. The
number of grid points- in the interval count was varied to determine their effect on computed flow.
Present work has done with three levels of grids in order to check the grid dependency over re-entry bodies. One
grid was meshed with an edge interval count of 100, second was with 150 and a third (fine mesh) with an edge interval count
of 200. Results are shown only for 200 interval count mesh. From the study made on three levels of meshes only afterbody
region is varied a little in the range of 10 -2 compared to the fine mesh. Forebody flow properties varied less than 1.3% on all
grids tested (slightly larger deviations were seen at the separation point due to numerical issues with some grids of interval
count 100 and 150).
The baseline grid has 200 points along the body surface and 120 points in the normal direction. Wall spacing was
chosen to maintain a constant cell Reynolds number, which implies that the near-wall spacing in the low-density afterbody is
much larger than on the forebody.
V. RESULTS AND ANALYSIS
During the development and flights of APOLLO, no numerical methods with adequate quality for complete flow
field simulations at corresponding trajectory points were available. Pre-flight predictions and post-flight comparisons were
done with analytical relations mainly developed for predicting the forward stagnation point heating. This paper demonstrates
the importance of understanding the effects of shock waves and illustrates how small change in flight attitude can alter the
resulting aerodynamic forces on the capsule. Finally, any minor alteration to the shape of the craft will also have great
implications. The temperature fields along the two vehicle bodies, OREX and FIRE II, will be discussed.
The process of diminishing the error was done iteratively using the CFD tool Fluent. After a number of the cases
were reviewed in which the solver gave the acceptable results for the fine grid for which the solutions are presented. Flow
simulations were carried at different Angles of Attack (AoA), with initial freestream conditions listed in Table I. The
solutions are in the range Mach 3 to 5, which spans the shock variations along its entry into atmosphere.
D. Physical Interpretation
The computed velocity vector plots over FIRE II & OREX are shown in Fig. 3. The red lines indicate areas of
higher intensity, while the blue just the opposite and the circulation and behind the body there is a disk shock. Close-up
views of the velocity vector plot over fore-body of the capsules and schematic shock location are depicted in the figure.
Disc Shock
Fig. 3 Shock induced flow over FIRE II & OREX at hypersonic speeds
E. Comparison between Supersonic and Hypersonic flows
Comparision of flows is shown in the fig. 4 and 5, It is observed that the distance between the shock wave and the
heat shield of the OREX capsule decreases from Mach 3 to 5 i.e., the shock wave formed comes closer to the body with
increase in mach number.
31
4. Flow Simulation over Re-Entry Bodies at Supersonic & Hypersonic Speeds
Comparing with theoretical normal shock relations formula, i.e., affable
where the M1 is the mach number before shock and M2 is after the shock and γ we get the following results;
M2 = 0.474 for supersonic speed (Mach 3)
M2 = 0.415 for hypersonic speed (Mach 5)
The computational values of Mach number across the shock wave are;
M2 = 0.481 for supersonic speed (Mach 3)
M2 = 0.417 for hypersonic speed (Mach 5)
As observed, the theoretically calculated values and the values obtained from FLUENT contours for the mach number
immediately after the shock wave are matching. Similar trends were observed for FIRE II re-entry capsule.
Fig. 4 Mach contour lines at Supersonic Speed over OREX & FIRE II.
Fig. 5 Mach Contour lines at hypersonic speeds over OREX & FIRE II.
F. Effects of Angle of Attack
The angle-of-attack has a definite effect on the physical properties of the craft. In Fig. 7 the vehicle is at an angle
of -20°, while in Fig. 7 at an angle of -40° and at -60° in Fig. 8. Results such as these are important to understand in the
sudden case that the re-entry vehicle becomes unstable and begins to rotate freely, in hopes of understanding a way to
counteract this occurrence. At -40 AoA (fig.7), illustrating the mach contour, we can see the unique structures forming in the
tail portion of the flow, as flow comes close to rest on the heat shield of the vehicle, as well as on the rear. Changing the
angle even further will illustrate further the great shift in dynamics. Fig. 7 displays the mach contour lines that would result
with an angle of -40°, while Fig. 8, with an angle of -60°, shows the velocity contour lines that would result. Fig. 8 clearly
shows how this change in angle affects the flow behind the re-entry vehicle. If the FIRE II capsule was coming at a zero
degree angle, we could expect the streamlines just off the rear of the spacecraft to be also at a zero degree angle. However,
with an angle of -40°, we observe how the streamlines would cross, causing a turbulent flow. With fig. 9, this is the first
instance we find the shock switch from a normal shockwave to an oblique shockwave. This is because the normal shock
wave changes to oblique when the angle, formed between the surface of the vehicle and the free stream, exceeds 45°, as one
can see with this angle-of-attack of -60°. The normal shockwave over the heat shield is desired as this change in kinetic
energy is what slows the re-entry vehicle as it enters the earth’s atmosphere at such great speeds as a Mach number of 2.5.
32
5. Flow Simulation over Re-Entry Bodies at Supersonic & Hypersonic Speeds
We will not observe this same change in energy with an oblique shockwave; therefore it is vital to keep this angle-of-attack
from shifting less than 45° in either direction.
Fig. 6 Mach Contour lines over FIRE II at -20 AoA
Fig. 7 Mach Contour lines over FIRE II & OREX at -40 AoA
Fig. 8 Mach Contour lines over FIRE II & OREX at -60 AoA
G. Vehicle Shape Analysis
For different shapes of re-entry capsules, there is a long tail that extends out from the back, whose shape will differ
between re-entry vehicles. To illustrate the difference between the FIRE II and OREX designs, we may observe the
temperature variances as seen in Fig. 9. Here we can see that the general shape of the shock wave itself is practically
identical, however, the differences lie in the rear of the object. The most dangerous difference is the great amount of heat
generated on the rear of the craft.
33
6. Flow Simulation over Re-Entry Bodies at Supersonic & Hypersonic Speeds
Fig. 9 Temperature Contour lines over FIRE II & OREX at hypersonic speeds
VI. CONCLUSIONS
The Apollo shape re-entry capsule is one topic that has resurfaced as a result of dependability. Due to this interest,
the analysis of such a craft especially with the increasingly better technological methods such as the advancements in CFD,
has also become very important. This paper exemplifies this importance. Physically, the aerodynamic forces effect on the
motion of re-entry vehicle, especially at such high speeds, that even a slight change in angle of attack can severely alter the
activity of the re-entry capsule including the shock way which plays such a big factor in the fate of the craft. A slight change
in the vehicle shape can alter the dynamics of the craft. As the vehicle reaches lower altitudes a lift maneuver acts on the
vehicle and creates a large impact footprint. It does qualitative analyses of the patterns or rules associated with aerodynamic
forces as they follow changes in the geometrical parameters of vehicles or bodies, having important reference value for the
design of reentry bodies or vehicles. Characteristics flow features around the blunt body at supersonic & hypersonic speeds
is observed. The high surface pressure on the fore-body results the development of high aerodynamic drag which is required
for the aerobraking application. Results adequately explain that, in a situation where angle of attack changes, the
asymmetries in the nose section cause flow fields to be non-uniform, and, in conjunction with that, there are obvious
influences on the afterbody.
REFERENCES
[1]. R C Mehta, Computations of flow field over Apollo and OREX reentry modules at high speed, Indian Journal of Engineering &
Materials Sciences, , December 2008, Vol.15.
[2]. Michael Wright, Mark Loom and Periklis Papadopoulos, Aerothermal Analysis of the Project Fire II Afterbody Flow, AIAA,
2001.
[3]. R C Mehta, Numerical Simulation of Supersonic Flow Past Reentry Capsules, Journal of Shock waves, Vol. 15, 2006.
[4]. Ernst-Heinrich Hirschel, Claus Weiland, Aerothermodynamic Design Problems of Hypersonic Flight Vehicles, Springer, 2008.
[5]. Hirschel, E.H., Basics of Aerothermodynamics, progress in Astronautics and Aeronautics, AIAA, Reston, Vol.204. Springer,
2004.
[6]. Roop N. Gupta, Jim J. Jones, and William C. Rochelle, Stagnation-Point Heat-Transfer Rate Predictions at Aeroassist Flight
Conditions, NASA TP-3208, NASA-Langley, 1992.
[7]. M. S. Ivanov and S. F. Gimelshein, Computational Hypersonic Rarefied Flows, Annual Rev. Fluid mech. Vol. 30:pp. 469–505,
1998.
[8]. Braun, R. D. and Manning, R. M., Mars Exploration Mars Exploration Entry, Descent and Landing Challenges, Paper 1076,
2006 IEEE Aerospace Conference, Big Sky, Montana, March 2006.
[9]. Mitcheltree, R. A., DiFulvio, M., Horvath, T.J., and Braun, R. D., Aerothermal Heating Predictions for Mars Microprobe, AIAA
Paper No. 98-0170, Jan. 1998.
[10]. R C Mehta, Computations of Flowfield over Reentry Modules at High Speed, Computational Simulations and Applications, 2009.
[11]. Christopher J. Roy and Frederick G. Blottner, Assessment of One- and Two-Equation Turbulence Models for Hypersonic
Transitional Flows, Journal Of Spacecraft and Rockets, Vol. 38, No. 5, September–October 2001.
Contributors
Mr. Shiva Prasad U. obtained his M. Tech (Aerospace Engineering) from Institute of Aeronautical Engineering,
Hyderabad, A.P. Presently, he is working as Asst. Prof. in the Dept. of Aeronautical Engineering, Manipal Institute of
Technology, Manipal University (MU-MIT), Manipal. His research interests include: CFD, Hypersonic Aerodynamics,
Propulsion and Combustion. He has Four International conference publications to his credit.
Mr. Srinivas. G obtained his M. Tech (Aerospace Engineering) from Institute of Aeronautical Engineering, Hyderabad,
A.P. Presently, he is working as Asst. Prof. in the Dept. of Aeronautical Engineering, Manipal Institute of Technology,
Manipal University (MU-MIT), Manipal. His research interests include: CFD, Aerodynamics, and propulsion. He has 4
conference publications to his credit.
34