1) The document investigates the drag effects of different orientations of corrugations on plastic rocket fins through wind tunnel testing and computational fluid dynamics modeling.
2) Two fin designs were tested - one with corrugations parallel to the leading edge and one with corrugations parallel to the root chord. It was hypothesized that the latter configuration would have less drag.
3) Both the wind tunnel tests and CFD simulations supported the hypothesis, finding that fins with corrugations parallel to the root chord experienced approximately 2% less drag on average than those with corrugations parallel to the leading edge.
This document provides an inventory and stress analysis of microphone struts used at NASA's National Full-Scale Aerodynamics Complex (NFAC). 21 microphone struts were identified and measured. Strut airfoils were analyzed in XFLR5 to determine lift and drag coefficients. Handwritten stress analyses were performed on the struts and critical points to calculate stresses, factors of safety, and recommended maximum wind tunnel speeds. The secondary objective was to find a strut capable of safely operating at 300 knots in the 40-by-80 Foot Wind Tunnel for an upcoming test of the Tilt-Rotor Test Rig. Finite element analyses using Creo were also planned to further analyze strut stresses.
1) The document discusses two projects involving particle image velocimetry (PIV) - an analysis of fluid flow through a 90 degree pipe bend, and an identification of trailing-edge noise in buffet flows using high-speed PIV.
2) For the pipe bend project, PIV was used to capture images of fluid flow at different rates, showing dual vortices known as Dean Vortices. As flow rate increased, velocity in the upper right corner also increased while vortical structure diminished.
3) For the buffet flow project, high-speed stereo PIV was used to investigate shock oscillations on a supercritical airfoil. Trailing edge turbulent eddies were suspected of generating
Probing the Hurricane Boundary Layer using NOAA's Research AircraftJun Zhang
Jun Zhang presented this work during his short visit at NCAR in June 2011. Below is the abstract of this talk:
The boundary layer is known to play an important role in the energy transport processes of a hurricane, regulating the radial and vertical distribution of momentum and enthalpy that are closely related to storm development and intensification. However, the hurricane boundary layer is the least observed part of a storm till now. In particular, there is a lack of turbulence observation due to instrumentation limitation and safety constraint. This talk will present aircraft observations of the atmospheric boundary layer structure in intense hurricanes. Turbulence data presented are related to topics of air-sea exchange of turbulent fluxes, turbulent kinetic energy budget, dissipative heating, and vertical mixing in the boundary layer. The question of how to define the top of the hurricane boundary layer is also discussed.
Numerical and experimental investigation of co shedding vortex generated by t...Alexander Decker
The document investigates the effect of co-shedding vortices generated by two adjacent circular cylinders on air flow behavior around an NACA 2412 airfoil. Both experimental and numerical methods were used. Experimentally, a smoke wind tunnel was used to visualize flow at different velocities and angles of attack. Numerically, ANSYS was used to simulate results. The study found that the vortices induced turbulence upstream of the airfoil, preventing separation and allowing reattachment of the flow. Both methods showed that increasing angle of attack or velocity shifted the separation point toward the leading edge. The vortices generated by the cylinders thus helped control flow separation around the airfoil.
This document discusses prelaunch testing and post-launch validation plans for the Advanced Technology Microwave Sounder (ATMS) on the NPP satellite. Key points:
- ATMS underwent antenna pattern testing using a Compact Antenna Test Range to verify beam pointing accuracy and efficiency. Radiometric thermal vacuum testing validated the sensor meets specifications and defined calibration parameters.
- Post-launch calibration/validation has four phases: activation, checkout, intensive calibration/validation, and long-term trending. It involves evaluating sensor performance, verifying data records, tuning algorithms, and using techniques like satellite maneuvers and simultaneous nadir overpasses.
- Plans aim to fully characterize the sensor and produce high-quality
This experiment studied standing waves by measuring the length of an air column needed to produce resonance at different tuning fork frequencies. The length increased as the period of the tuning fork increased. Graphs of frequency vs. length and period vs. length showed a linear relationship. Only 3 data points were within the trend, limiting accuracy. Using more tuning forks and tubes of varying diameters could improve the experiment.
The document summarizes an experimental and numerical study of the effect of sweep on the three-dimensional flow downstream of axial flow fans. Three low-pressure axial flow fans were studied, with radial, forward, and backward sweep. Hot-wire anemometry was used to measure the velocity components downstream, and computational fluid dynamics (CFD) simulations using Reynolds-averaged Navier-Stokes (RANS) were performed for comparison. The results show that forward sweep decreases the radial velocity component while backward sweep increases it. The sweep also significantly influences the turbulent kinetic energy downstream of the fan.
1) This document summarizes an experiment to determine the center of pressure on a partially submerged plane surface. Tables of recorded data show close agreement between experimental and theoretical values.
2) A second part of the experiment aimed to determine the position of the center of pressure of a fully submerged plane surface, but results showed a 75% discrepancy between experimental and theoretical values.
3) Factors like parallax errors, random errors, water impurities, and bubbles could explain the discrepancies. Careful measurement and repeated trials could improve accuracy. The findings are relevant to submarine hull design to withstand high hydrostatic pressures at depth.
This document provides an inventory and stress analysis of microphone struts used at NASA's National Full-Scale Aerodynamics Complex (NFAC). 21 microphone struts were identified and measured. Strut airfoils were analyzed in XFLR5 to determine lift and drag coefficients. Handwritten stress analyses were performed on the struts and critical points to calculate stresses, factors of safety, and recommended maximum wind tunnel speeds. The secondary objective was to find a strut capable of safely operating at 300 knots in the 40-by-80 Foot Wind Tunnel for an upcoming test of the Tilt-Rotor Test Rig. Finite element analyses using Creo were also planned to further analyze strut stresses.
1) The document discusses two projects involving particle image velocimetry (PIV) - an analysis of fluid flow through a 90 degree pipe bend, and an identification of trailing-edge noise in buffet flows using high-speed PIV.
2) For the pipe bend project, PIV was used to capture images of fluid flow at different rates, showing dual vortices known as Dean Vortices. As flow rate increased, velocity in the upper right corner also increased while vortical structure diminished.
3) For the buffet flow project, high-speed stereo PIV was used to investigate shock oscillations on a supercritical airfoil. Trailing edge turbulent eddies were suspected of generating
Probing the Hurricane Boundary Layer using NOAA's Research AircraftJun Zhang
Jun Zhang presented this work during his short visit at NCAR in June 2011. Below is the abstract of this talk:
The boundary layer is known to play an important role in the energy transport processes of a hurricane, regulating the radial and vertical distribution of momentum and enthalpy that are closely related to storm development and intensification. However, the hurricane boundary layer is the least observed part of a storm till now. In particular, there is a lack of turbulence observation due to instrumentation limitation and safety constraint. This talk will present aircraft observations of the atmospheric boundary layer structure in intense hurricanes. Turbulence data presented are related to topics of air-sea exchange of turbulent fluxes, turbulent kinetic energy budget, dissipative heating, and vertical mixing in the boundary layer. The question of how to define the top of the hurricane boundary layer is also discussed.
Numerical and experimental investigation of co shedding vortex generated by t...Alexander Decker
The document investigates the effect of co-shedding vortices generated by two adjacent circular cylinders on air flow behavior around an NACA 2412 airfoil. Both experimental and numerical methods were used. Experimentally, a smoke wind tunnel was used to visualize flow at different velocities and angles of attack. Numerically, ANSYS was used to simulate results. The study found that the vortices induced turbulence upstream of the airfoil, preventing separation and allowing reattachment of the flow. Both methods showed that increasing angle of attack or velocity shifted the separation point toward the leading edge. The vortices generated by the cylinders thus helped control flow separation around the airfoil.
This document discusses prelaunch testing and post-launch validation plans for the Advanced Technology Microwave Sounder (ATMS) on the NPP satellite. Key points:
- ATMS underwent antenna pattern testing using a Compact Antenna Test Range to verify beam pointing accuracy and efficiency. Radiometric thermal vacuum testing validated the sensor meets specifications and defined calibration parameters.
- Post-launch calibration/validation has four phases: activation, checkout, intensive calibration/validation, and long-term trending. It involves evaluating sensor performance, verifying data records, tuning algorithms, and using techniques like satellite maneuvers and simultaneous nadir overpasses.
- Plans aim to fully characterize the sensor and produce high-quality
This experiment studied standing waves by measuring the length of an air column needed to produce resonance at different tuning fork frequencies. The length increased as the period of the tuning fork increased. Graphs of frequency vs. length and period vs. length showed a linear relationship. Only 3 data points were within the trend, limiting accuracy. Using more tuning forks and tubes of varying diameters could improve the experiment.
The document summarizes an experimental and numerical study of the effect of sweep on the three-dimensional flow downstream of axial flow fans. Three low-pressure axial flow fans were studied, with radial, forward, and backward sweep. Hot-wire anemometry was used to measure the velocity components downstream, and computational fluid dynamics (CFD) simulations using Reynolds-averaged Navier-Stokes (RANS) were performed for comparison. The results show that forward sweep decreases the radial velocity component while backward sweep increases it. The sweep also significantly influences the turbulent kinetic energy downstream of the fan.
1) This document summarizes an experiment to determine the center of pressure on a partially submerged plane surface. Tables of recorded data show close agreement between experimental and theoretical values.
2) A second part of the experiment aimed to determine the position of the center of pressure of a fully submerged plane surface, but results showed a 75% discrepancy between experimental and theoretical values.
3) Factors like parallax errors, random errors, water impurities, and bubbles could explain the discrepancies. Careful measurement and repeated trials could improve accuracy. The findings are relevant to submarine hull design to withstand high hydrostatic pressures at depth.
Compensation of time-varying clock-offset in a LBL navigationjournalBEEI
This paper presents compensation of the clock-offset in a long baseline (LBL)navigation. It departs from the existing literature mainly in dealing with a time-varyingclock-offset, i.e. the clock-rate drifts over the time. Specifically, the clock-offsetdynamics are introduced to the ToFs as an autoregressive filter.Subsequently,interactions among the now biased ToFs and the kinematics of an autonomousunderwater vehicle (AUV)–the navigation subject–are represented in a state-spaceform. Implementing the so-called graphic approach, minimum sensor requirementfor this system’s observability is then explicated. Finally, a standard discrete Kalmanfilter is deployed as the state estimator. By simulation, it is demonstrated that theestimator manages to compensate the offset and to provide localization with less than1 m accuracy.
This study examines the effect of rain on ASCAT observations of sea surface radar cross-section using simultaneous rain measurements from NEXRAD radars. Three rain events were analyzed over Gulf of Mexico in 2008-2009. Results show rain can cause substantial increases in backscatter, from 2-4 dB depending on incidence angle, leading to errors in estimated wind speed of around 60%. The change in backscatter was found to depend on incidence angle but consequences were similar across angles due to wind speed models. Substantial wind errors were identified for rain rates of 6-20 mm/hr. Extra care is needed when using ASCAT data in tropical rainy regions.
The document summarizes the development and characteristics of several airfoil series developed by the National Advisory Committee for Aeronautics (NACA). It describes the early 4-digit and 5-digit series which used analytical equations to define airfoil shape based on camber and thickness. Later series like the 6-series used more advanced theoretical methods. The document provides details on naming conventions and equations used to define the geometry of airfoils within each series.
Aircraft propulsion non ideal turbomachine 2 dAnurak Atthasit
This document outlines the topics and content covered in a unit on 2-D analysis in turbomachinery flow with loss taught from 2005-2010. The unit covered 2-D blade design criteria such as diffusion factor and degree of reaction. It also covered 2-D flow analysis for blades with loss, including isentropic/polytropic loss, loss coefficient, and work done factor. The document provides examples of these concepts and notes they were practiced in class.
The document summarizes numerical simulations of the flow inside a centrifugal compressor's vaneless diffuser and volute. Gambit was used to generate meshes of the geometries, and Fluent was used to simulate the flows. Results from simulations at different speeds and mass flows agreed well with experimental data. The simulations showed separated flow on the diffuser hub wall at low mass flows. Inside the volute, swirling flow structures like vortices were observed. The tongue region caused static pressure distortions that affected the flow.
Energy Budget in Tunnel Fires – FFFS ConsiderationsWSP
Presentation delivered by Matthew Bilson and Katie McQuade from WSP | Parsons Brinckerhoff in the USA, on March 16, 2016 at the 7th International Symposium on Tunnel Safety and Security (ISTSS) held in Montreal, Canada.
The document summarizes the results of a detailed flow investigation within a centrifugal pump equipped with a vaned diffuser. Unsteady velocity measurements were obtained in the impeller and diffuser at different radial planes. The analysis shows the presence of a complex, unsteady and periodic jet-wake flow structure in the impeller. At the impeller discharge, the mixing of the unsteady flow entering the diffuser is affected by the diffuser vanes, though periodic flow characteristics are still observed at the diffuser throat, indicating unsteady inlet conditions for the diffuser.
- The document summarizes responses to questions about wave and hydrodynamic modeling for the Gulf of Thailand Early Warning System.
- It describes that SWAN was used for wave modeling with a 300m resolution, and wave setup was estimated using an empirical equation rather than direct modeling. Delft3D Flexible Mesh was used for hydrodynamic modeling with a Courant-adaptive grid and horizontal viscosities of 1 m^2/s.
- The models were not online coupled, and wind forcing, boundaries, and water levels were handled separately rather than exchanged between the wave and hydrodynamic models.
This document contains questions related to the IMDG Code, firefighting procedures, spillage procedures, weather instruments, navigation equipment, and the ISM Code. It includes questions about 3 different dangerous goods, actions to take in case of a cargo fire on deck or under deck, washing spillage on deck, protecting against corrosion from spillage under deck, the setup and use of a Mason's hygrometer, Stevenson screen, gyro compass, GPS including errors and setup, radar usage including sea stabilization, ECDIS chart types, advantages and disadvantages of AIS, draft and fresh water allowances, barometer corrections, hydrometers, hygrometers, and requirements and goals of the ISM Code.
This presentation had been prepared for the aircraft propulsion class to my undergraduate and graduate students at Kasetsart University and Chulalongkorn University - Bangkok, Thailand.
IRJET- Experimental Investigation of Flow through Perforated Plate in Conical...IRJET Journal
This document describes an experimental investigation of flow through a perforated plate inside a conical diffuser. The goal is to improve the axial flow and achieve higher static pressure rise without total pressure loss. A supersonic wind tunnel was used to test a conical diffuser with an angle of 7 degrees that had two perforated plates placed inside at a distance of 450mm from the inlet. Pressure values were measured using a manometer at various ports and the coefficient of pressure was calculated both without and with the perforated plates. The results found that the addition of the perforated plates improved the flow uniformity and increased the static pressure rise inside the diffuser compared to when no plates were used.
The document describes an experimental study on vortex shedding behind a trapezoidal bluff body using flow visualization. The study aims to calculate vortex formation length, identify the Strouhal number and wake width. Flow visualization is used to understand the complex vortex formation mechanism. An experimental setup is fabricated with a trapezoidal bluff body placed inside a circular pipe. Dye injection technique is employed to visualize vortex patterns. Various wake parameters will be derived from the flow visualization images to improve the understanding and design of vortex flow meters.
A high speed wind tunnel test was conducted on a Gill Windobserver 1390-90-B-121 ultrasonic anemometer with serial number 152199. The anemometer was tested at wind speeds from 5 to 90 m/s in 15 degree increments with its orientation fixed at 45 degrees. Graphs comparing the anemometer measurements to the wind tunnel air flow speed showed close agreement between the two across all tested wind speeds. Additionally, a yaw sweep test was performed at 45 m/s which analyzed the anemometer's response to changing wind directions.
Worked Examples for Timber Beam Design to AS1720.1 WebinarClearCalcs
This document analyzes a timber beam used as a floor bearer. It summarizes the demands on the beam from different load cases, including moment, shear, bearing and deflection. The governing load cases are identified as 1.2G, 1.5Q for moment, shear and bearing demands. Short-term deflection is governed by load case G, Q_st, while long-term deflection is governed by G, Q_lt. The beam properties, load cases, demands and capacities are analyzed according to AS1720.1:2010 timber design standard.
Este documento usa la metáfora de la vida como un viaje en tren, con nacimiento, relaciones, pérdidas y muerte como paradas a lo largo del camino. Se sube al tren con los padres, pero eventualmente ellos se bajan, aunque se conocen nuevas personas que traen alegría. La vida está llena de desafíos y emociones encontradas. Al final, uno espera haber vivido plenamente y dejar buenos recuerdos a los demás pasajeros antes de bajar en la estación final.
Este documento resume las funciones estadísticas en Excel como promedio, máximo, mínimo y desviación estándar. Explica cómo usar estas funciones para obtener valores estadísticos clave de conjuntos de datos y cómo distribuir datos en tablas de frecuencia. También describe herramientas estadísticas adicionales en Excel para análisis avanzados.
Compensation of time-varying clock-offset in a LBL navigationjournalBEEI
This paper presents compensation of the clock-offset in a long baseline (LBL)navigation. It departs from the existing literature mainly in dealing with a time-varyingclock-offset, i.e. the clock-rate drifts over the time. Specifically, the clock-offsetdynamics are introduced to the ToFs as an autoregressive filter.Subsequently,interactions among the now biased ToFs and the kinematics of an autonomousunderwater vehicle (AUV)–the navigation subject–are represented in a state-spaceform. Implementing the so-called graphic approach, minimum sensor requirementfor this system’s observability is then explicated. Finally, a standard discrete Kalmanfilter is deployed as the state estimator. By simulation, it is demonstrated that theestimator manages to compensate the offset and to provide localization with less than1 m accuracy.
This study examines the effect of rain on ASCAT observations of sea surface radar cross-section using simultaneous rain measurements from NEXRAD radars. Three rain events were analyzed over Gulf of Mexico in 2008-2009. Results show rain can cause substantial increases in backscatter, from 2-4 dB depending on incidence angle, leading to errors in estimated wind speed of around 60%. The change in backscatter was found to depend on incidence angle but consequences were similar across angles due to wind speed models. Substantial wind errors were identified for rain rates of 6-20 mm/hr. Extra care is needed when using ASCAT data in tropical rainy regions.
The document summarizes the development and characteristics of several airfoil series developed by the National Advisory Committee for Aeronautics (NACA). It describes the early 4-digit and 5-digit series which used analytical equations to define airfoil shape based on camber and thickness. Later series like the 6-series used more advanced theoretical methods. The document provides details on naming conventions and equations used to define the geometry of airfoils within each series.
Aircraft propulsion non ideal turbomachine 2 dAnurak Atthasit
This document outlines the topics and content covered in a unit on 2-D analysis in turbomachinery flow with loss taught from 2005-2010. The unit covered 2-D blade design criteria such as diffusion factor and degree of reaction. It also covered 2-D flow analysis for blades with loss, including isentropic/polytropic loss, loss coefficient, and work done factor. The document provides examples of these concepts and notes they were practiced in class.
The document summarizes numerical simulations of the flow inside a centrifugal compressor's vaneless diffuser and volute. Gambit was used to generate meshes of the geometries, and Fluent was used to simulate the flows. Results from simulations at different speeds and mass flows agreed well with experimental data. The simulations showed separated flow on the diffuser hub wall at low mass flows. Inside the volute, swirling flow structures like vortices were observed. The tongue region caused static pressure distortions that affected the flow.
Energy Budget in Tunnel Fires – FFFS ConsiderationsWSP
Presentation delivered by Matthew Bilson and Katie McQuade from WSP | Parsons Brinckerhoff in the USA, on March 16, 2016 at the 7th International Symposium on Tunnel Safety and Security (ISTSS) held in Montreal, Canada.
The document summarizes the results of a detailed flow investigation within a centrifugal pump equipped with a vaned diffuser. Unsteady velocity measurements were obtained in the impeller and diffuser at different radial planes. The analysis shows the presence of a complex, unsteady and periodic jet-wake flow structure in the impeller. At the impeller discharge, the mixing of the unsteady flow entering the diffuser is affected by the diffuser vanes, though periodic flow characteristics are still observed at the diffuser throat, indicating unsteady inlet conditions for the diffuser.
- The document summarizes responses to questions about wave and hydrodynamic modeling for the Gulf of Thailand Early Warning System.
- It describes that SWAN was used for wave modeling with a 300m resolution, and wave setup was estimated using an empirical equation rather than direct modeling. Delft3D Flexible Mesh was used for hydrodynamic modeling with a Courant-adaptive grid and horizontal viscosities of 1 m^2/s.
- The models were not online coupled, and wind forcing, boundaries, and water levels were handled separately rather than exchanged between the wave and hydrodynamic models.
This document contains questions related to the IMDG Code, firefighting procedures, spillage procedures, weather instruments, navigation equipment, and the ISM Code. It includes questions about 3 different dangerous goods, actions to take in case of a cargo fire on deck or under deck, washing spillage on deck, protecting against corrosion from spillage under deck, the setup and use of a Mason's hygrometer, Stevenson screen, gyro compass, GPS including errors and setup, radar usage including sea stabilization, ECDIS chart types, advantages and disadvantages of AIS, draft and fresh water allowances, barometer corrections, hydrometers, hygrometers, and requirements and goals of the ISM Code.
This presentation had been prepared for the aircraft propulsion class to my undergraduate and graduate students at Kasetsart University and Chulalongkorn University - Bangkok, Thailand.
IRJET- Experimental Investigation of Flow through Perforated Plate in Conical...IRJET Journal
This document describes an experimental investigation of flow through a perforated plate inside a conical diffuser. The goal is to improve the axial flow and achieve higher static pressure rise without total pressure loss. A supersonic wind tunnel was used to test a conical diffuser with an angle of 7 degrees that had two perforated plates placed inside at a distance of 450mm from the inlet. Pressure values were measured using a manometer at various ports and the coefficient of pressure was calculated both without and with the perforated plates. The results found that the addition of the perforated plates improved the flow uniformity and increased the static pressure rise inside the diffuser compared to when no plates were used.
The document describes an experimental study on vortex shedding behind a trapezoidal bluff body using flow visualization. The study aims to calculate vortex formation length, identify the Strouhal number and wake width. Flow visualization is used to understand the complex vortex formation mechanism. An experimental setup is fabricated with a trapezoidal bluff body placed inside a circular pipe. Dye injection technique is employed to visualize vortex patterns. Various wake parameters will be derived from the flow visualization images to improve the understanding and design of vortex flow meters.
A high speed wind tunnel test was conducted on a Gill Windobserver 1390-90-B-121 ultrasonic anemometer with serial number 152199. The anemometer was tested at wind speeds from 5 to 90 m/s in 15 degree increments with its orientation fixed at 45 degrees. Graphs comparing the anemometer measurements to the wind tunnel air flow speed showed close agreement between the two across all tested wind speeds. Additionally, a yaw sweep test was performed at 45 m/s which analyzed the anemometer's response to changing wind directions.
Worked Examples for Timber Beam Design to AS1720.1 WebinarClearCalcs
This document analyzes a timber beam used as a floor bearer. It summarizes the demands on the beam from different load cases, including moment, shear, bearing and deflection. The governing load cases are identified as 1.2G, 1.5Q for moment, shear and bearing demands. Short-term deflection is governed by load case G, Q_st, while long-term deflection is governed by G, Q_lt. The beam properties, load cases, demands and capacities are analyzed according to AS1720.1:2010 timber design standard.
Este documento usa la metáfora de la vida como un viaje en tren, con nacimiento, relaciones, pérdidas y muerte como paradas a lo largo del camino. Se sube al tren con los padres, pero eventualmente ellos se bajan, aunque se conocen nuevas personas que traen alegría. La vida está llena de desafíos y emociones encontradas. Al final, uno espera haber vivido plenamente y dejar buenos recuerdos a los demás pasajeros antes de bajar en la estación final.
Este documento resume las funciones estadísticas en Excel como promedio, máximo, mínimo y desviación estándar. Explica cómo usar estas funciones para obtener valores estadísticos clave de conjuntos de datos y cómo distribuir datos en tablas de frecuencia. También describe herramientas estadísticas adicionales en Excel para análisis avanzados.
The document discusses the social media strategies and growth of the Career Resource Center (CRC) and Office of Internships and Experiential Learning (IEL) at the University at Buffalo. It shows that both CRC and IEL have significantly grown their social media presence in the past year. IEL's Facebook likes increased 413% in the last month and their posts now regularly reach 180-200 people. CRC also grew their Facebook likes and average post reach has increased 93.8% due to posting more photos and videos. The document attributes this growth to improved posting content like photos and videos, analyzing posting times and engagement, and maintaining a presence on multiple platforms to connect with students.
O Olist conecta vendedores a grandes canais de vendas online no Brasil para facilitar a distribuição de produtos. Começou em 2007 como uma loja física de artesanato e evoluiu para uma plataforma online em 2011, conectando mais de 8 mil usuários. Em 2015, tornou-se uma startup com 12 funcionários e investimento para expansão.
LTG Mary Legere had a long and distinguished 29-year career in the U.S. Army, becoming one of only four women to attain the rank of three-star general. She served as a senior intelligence officer and principal advisor to the Secretary of the Army on intelligence and security policy. During her career, she oversaw experiments integrating big data, fusion and multi-discipline approaches to guide the Army's transition to cloud computing and common operating environments.
This document summarizes the different ways a contract can be discharged. It discusses discharge by performance when both parties fulfill their obligations, discharge by breach when one party fails to meet their obligations, discharge by agreement when parties mutually agree to end the contract, and discharge by frustration when an unforeseen event makes performance impossible. Remedies for breach of contract are also outlined, including damages to compensate for losses, quantum meruit payments for partial work, and specific performance or injunctions to enforce the contract.
The document discusses various modes of discharge of a contract under Indian law. It defines discharge of a contract as cessation of rights and obligations of parties to a contract. There are several modes of discharge, including performance, agreement between parties, operation of law such as death or bankruptcy of a party, impossibility of performance, breach of contract, lapse of time. The key modes discussed are discharge by performance, agreement, frustration, breach of contract, and lapse of time as defined in relevant sections of the Indian Contract Act.
El documento discute las tendencias del mercado laboral actual como la terciarización del trabajo y la obsolescencia veloz. Explica que la economía se ha movido hacia el sector de servicios y que las habilidades se vuelven obsoletas rápidamente. También describe varios tipos de flexibilidad laboral como mecanismos para que las empresas se adapten a los cambios, así como la importancia del capital humano y la capacitación laboral para mantener la productividad de los trabajadores.
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.
The document discusses aerodynamic analysis of the NACA 0012 airfoil using computational fluid dynamics (CFD). CFD simulations were performed in ANSYS Fluent to analyze flow behavior and calculate aerodynamic forces at varying angles of attack from 0 to 20 degrees. The results obtained from the CFD analysis matched theoretical predictions and experimental data. Key parameters like pressure and velocity distributions, lift and drag coefficients, and lift to drag ratios were evaluated to understand airfoil performance.
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
The document proposes designing and building a car-mounted thrust stand for dynamic testing of propellers as an alternative to traditional wind tunnel testing. Key details include:
- The setup would allow testing of propellers over 10 inches in diameter, which most universities cannot test in wind tunnels.
- Aerodynamic considerations require the propeller to be at least 5 times its diameter from the car roof to avoid blockage, and the largest propeller to be tested is 10 inches so the minimum height is set at 27 inches.
- Structural analysis shows the design has a safety factor of at least 1.6 under worst-case loads to remain safely attached to the car at high speeds.
Performance Analysis of savonius hydro turbine using CFD simulationIRJET Journal
This document analyzes the performance of a Savonius hydro turbine using computational fluid dynamics (CFD) simulations and experimental data. It discusses modeling the turbine geometry in SolidWorks and importing it into ANSYS for meshing and simulations. Velocity and pressure contours are presented for different turbine configurations and canal widths. The maximum power coefficient Cp is found to occur at a canal width of 5D. Experimental and simulated results are compared, finding good agreement. In conclusion, a canal width of 5D is determined to provide optimal Cp for the turbine design at low fluid velocities of 0.6 m/s.
IRJET- Aerodynamic Performance Analysis on a Wing with “M” Shaped Serrate...IRJET Journal
1. Researchers analyzed the aerodynamic performance of a wing with an "M" shaped serrated trailing edge using wind tunnel testing.
2. Results showed that the serrated trailing edge design produced up to 25% more lift and 61% less drag compared to a normal wing at certain angles of attack.
3. The maximum improvement in lift-to-drag ratio occurred at an angle of attack of 10 degrees. The study demonstrates that the "M" shaped serrated trailing edge can enhance the aerodynamic performance of wings.
The document provides information about conducting wind tunnel experiments for students in grades 8-12. It includes sample experiments such as measuring lift versus angle of attack and lift versus velocity. It also discusses governing equations, flow visualization techniques, how to make measurements, background on why wind tunnels are used, and selected references for further reading.
The document describes an experiment to measure the uniformity of velocity in a wind tunnel. A hot wire anemometer system was used to measure the absolute, axial, vertical, and perpendicular velocity values at 6 points as a probe was moved through the test section of the wind tunnel. The results showed a range of velocities from 26.12 to 39.18 m/s, indicating a lack of uniformity. Graphs of the velocity measurements also revealed deviations. It was concluded that the non-uniform flow was likely due to the wind tunnel's contraction ratio of 9, which is below the recommended ratio of around 16 needed to achieve uniform flow. Improving the design of the contraction and suction sides could help address the issue.
Determination of shock losses and pressure losses in ug mine openingsSafdar Ali
This document discusses determining pressure and shock losses in underground mine openings using computational fluid dynamics (CFD) simulation techniques. It aims to calculate losses in different mine configurations using CFD and compare results to classical formulas. The document outlines the objective, scope, literature review on losses, and CFD methodology. It describes setting up simulations of common mine geometries like tunnels, bends, junctions, and shafts in Gambit meshing software and analyzing them in Fluent. Results are presented on velocity profiles and pressure losses for configurations like gradual contractions and expansions.
Determination of shock losses and pressure losses in ug mine openings (1)Safdar Ali
This document discusses the determination of shock and pressure losses in underground mine openings using computational fluid dynamics (CFD) simulation techniques. The objective is to calculate losses in different mine configurations and compare results from CFD simulations to classical formulas. The document outlines the scope of the project, literature review on losses, and describes meshing mine geometries in Gambit and performing CFD simulations in Fluent. Results are presented for simulations of tunnels, bends, junctions, contractions, expansions, shafts, and regulators. CFD-generated shock loss coefficients are found to agree reasonably well with published values, except for splits/junctions and forcing shafts, which may be due to modeling limitations. The conclusion is that 3D
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1. Drag Effects of Corrugated Plastic Rocket Fin Design and Corrugation Orientation
Fayetta Clawson1
Navajo Technical University
Gary L. Brandt2
Northwest Indian College
Nomenclature
Cd = Coefficient of drag
CPLE = corrugations parallel to leading edge
CPRC = corrugations parallel to root cord
FML = Fluid Mechanics Lab, NASA Ames Research Center
LE = Leading edge
mV/V = millivolts per volt
NART = Native American Research Team
RC = Root chord
RotCFD = Rotor Computational Fluid Dynamics software
SP = Span
TE = Trailing edge
TP = Tip
fpm = Feet per minute
fps = Feet per second
Abstract
Corrugated plastic such as used in making political and other outdoorsigns,is often used to make fins for
air/water rockets. It is light and durable. A question often asked by the rocket builders is, “Which way do the
corrugations go, into the air flow, or does it matter?” This investigation will provide information about which
corrugation orientation, parallel to the air flow or parallel to the fin’s leading edge, is more efficient during flight.
The test goal is to learn which corrugation orientation will have less drag. Two clipped delta shaped (trapezoid) fin
plan forms were evaluated: one plan form has corrugations parallel to the fin’s root chord (CPRC) and one fin has
corrugations parallel to the fin’s leading edge (CPLE); Testing evaluated fin drag at constant angle of attack (0
degrees) and varied wind speeds for comparison. All testing was performed in the 24” x 24” Wind Tunnel
(Lifesaver) located in the Fluid Mechanics Lab at NASA Ames Research Center, (Figure 1) The two fins were also
analyzed in the RotCFD for comparison to the wind tunnel results.
1 Student, Industrial Engineering, Navajo Technical University
2 Faculty, Information Technology,Northwest Indian College
2. 1
Figure 1. 24” x 24” Wind Tunnel (Lifesaver)
I. Introduction
Corrugated plastic is an ideal material for water/air pressure rocket fins because it is readily available,
inexpensive, durable, and easy to shape with household tools. Many people have made rocket fins out of corrugated
plastic. Corrugated plastic stockis similar to corrugated cardboard in that there are corrugations or openings
between an upperand lower skin. Figure 2 presents a conceptualdrawing of corrugated plastic as well as an edge
view of a representative sample. The openings may have an effect on the air flow over the fins where one orientation
may exhibit less drag compared to the other orientation. To the knowledge of the author, no testing for drag has been
done on rocket fins made from this type of plastic. Two delta shaped (trapezoid) fins were tested to investigate
which corrugation orientation, parallel to the air flow or parallel to the fin’s leading edge,is more efficient during
flight. One fin had corrugation orientation parallel to the leading edge, and the other had corrugations parallel to the
root chord. RotCFD is used in the rotorcraft industry as a design tool that can carry out aerodynamic simulations.
Additional analysis was done with RotCFD by running simulation for both fin designs in order to view the simulated
flow dynamics.
Figure 2. Corrugated plastic drawing and edge view showing corrugations
3. 2
II. Hypothesis
It is hypothesized that the CPRC will be more efficient during flight by creating less drag. It is thought that
the drag will be reduced with the corrugations parallel to the air flow (Figure 3) because the air will flow through the
openings in the fins. It is thought that the drag will be higher with fins that have the corrugations parallel to the fin’s
leading edge (Figure 4) due to air blockage from the leading edge.
Figure 3. Corrugations parallel to the root cord. Figure 4. Corrugations parallel to the leading edge.
III Design Description
Testing was performed in the 24” x 24” Wind Tunnel (Lifesaver) in the Fluid Mechanics Lab (FML) at
NASA Ames Research Center. A test stand to hold the fins in place was made of light wood, wire, and Velcro
(Figure 5) and was mounted on the torque sensor (Figure 6) and then that assembly was mounted on the wind tunnel
along with an anemometer (Figure 7). An anemometer measured the tunnel’s wind speed in feet per minute and the
torque sensormeasured the torque generated by the drag over the test fin’s surface created by the wind. The torque
sensorwas calibrated to measure in grams.
Figure 5. Test stand concept (dimensions in inches) and the stand mounted on the torque sensor
Figure 6. Omega TQ201 Series Torque Sensor and digital display
4. 3
Figure 7. Test stand in place with anemometer sensor and display unit
Test models were made of corrugated plastic (Figure 2). The trapezoid shaped fins, known as clipped delta
fin design, (Figure 8) have dimensions of: RC = 6”, LE = 6.18”, TE = 6.18” SP = 6”, TP = 3” having a total area of
27 in2 Figure3 shows the corrugations parallel to the leading edge and air flow direction. Figures 3 and 4 showthe
corrugation orientation to the air flow direction.
Figure 8. Clipped Delta Fin
The torque load cell sensor has an output of 2 mV/V with a load range of 25 ounce-inches.The test stand
was mounted on the rotating shaft of the torque sensorwhich meant that any rotating movement of the test stand
would cause the torque sensorto display a reading.
First the stand was mounted to the torque sensor the combination of sensorand stand hereinafter referred to
as the fin mount, and then the torque sensorwas connected to a digital display instrument. A near frictionless pulley
was mounted and place behind the fin mount in such as fashion that the calibrating weights could be tied to a piece
of string in order to cause the torque sensorto register movement (Figure 9). Increasing gram weights were tied to
the string in order to collect a set of data points that would be used to convert the torque load cell readings to
equivalent grams. The fin mount was mounted in center of the exit end of the wind tunnel. The wind tunnelwas
turned on and torque readings were recorded to ensure that the drag of the fin mount did not exceed the load
capacity of the torque sensor.
5. 4
Figure 9. Torque sensor calibration setup
Next a fin was mounted on the fin mount. The fin was aligned at 0 degrees angle of attack to the wind flow
in order to eliminate drag created by any non-zero angle of attack. Angle of attack was determined by comparing its
position with graph paper placed on the wind tunnel's floor (Figure 10). Torque sensorreadings were recorded for
wind speeds from 0 to 1900 fpm and from 1900 to 0 feet per minute in approximately 200 fpm increments. Each
step increase or decrease took place after the anemometer indicated steady flow and the torque sensorsettled to a
near steady reading. This procedure was repeated for the second fin. Ten readings were recorded for the CPLE fin
and 9 readings were recorded for the CPRC fin.
Figure 10. Angle of attack calibration
6. 5
IV Analysis and Results
Added Weights and Torque
Sensor Readout
Grams Readout
5 41
5 42
7 59
17 141
Figure 11. Calibrating torque sensor for converting its readout to grams
Figure 11 illustrates how the weights and torque sensorreadouts were plotted and the data slope was
calculated to be 8.277. This meant that each torque reading had to be divided by 8.277 in order to obtain grams.
All of the data was converted in post processing to the appropriate units of fps, square feet, and pounds.
Coefficient of drag (Cd) was computed by using the formula
D = Cd½ ρ𝑣2
S
Drag=Drag Coefficient x ½ x Air Density x Air Velocity^2 x Area.
Cd =
𝐷
1
2
𝜌𝑣2 𝑆
y = 8.2778x + 0.3889
0
20
40
60
80
100
120
140
160
0 5 10 15 20
Readout
Grams
Torque Sensor Calibration
Read out
Linear (Read out)
7. 6
CPLE Test
Drag Cd
0.054763 0.75
0.12778 0.57
0.328577 0.53
0.529374 0.55
0.803188 0.49
1.296053 0.50
1.788918 0.49
2.13575 0.49
2.847666 0.50
CPRC Test
Drag Cd
0.05476281 0.53
0.182542702 0.50
0.492865294 0.49
1.077001939 0.43
1.642884314 0.43
2.24527523 0.43
2.811157605 0.43
1.734155665 0.43
Figure 12. Data collection
After the conversions,the data was plotted,and the results are shown in Figure 12.
Figure 13. Graphical results of wind tunnel tests. Velocity is in feet per second.
Calculating the difference between the Cd of the CPLE and the Cd of the CPRC gave an average of a 2%
difference. This indicates that the fin with the CPRC has slightly less drag than a fin with the CPLE.
Wind tunnel test results supported the hypothesis that a fin with the corrugations parallel to the air flow has
less drag than a fin with the corrugations parallel to the leading edge.
In all of the RotCFD images, the airflow is from the left. RotCFD analysis also supported the hypothesis.
Figures 14-16 are RotCFD generated images of the flow about the fin with the corrugations parallel to the leading
edge. Figures 17-19 are RotCFD generated images of the fin with the corrugations parallel to the air flow. Arrows
are vectors representing pressure with brightness indicating increasing pressure. Examining Figures 17-19, one can
see that the air flow over the fin with the corrugations parallel to the root chord has little turbulence. This creates
less drag.
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.0 10.0 20.0 30.0 40.0
CoefficientofDrage(Cd)
Velocity (fps)
Corrugated PlasticCoefficient of Drag
Leading Edge
Root Cord
8. 7
RotCFD images of fin with corrugations parallel to its leading edge
Figure 14. Cross section with Leading Edge on left Figure 15. Top view with Leading Edge on left
Figure 16. Front view looking down the span toward the root
RotCFD images of fin with corrugations parallel to air flow
Figure 17. Cross section with Leading Edge on left Figure 18. Top view with Leading Edge on left
Figure 19. Front view looking down the span toward the root
9. 8
V Conclusions
Wind tunnel tests and RotCFD modeling indicate that fins with CPRC have slightlyless drag than fins with
CPLE.
VI Acknowledgments
I would like to express my deepest appreciation to everyone who provided me the possibility to complete
my report. A special gratitude I give to my mentors Gary Brandt and Kurt Long, whose contribution to my project,
testing,and encouragement, helped me to coordinate my project especially in writing this report. I would also like to
thank AIHEC, TCUP, Navajo Technical University, the NART Team, Ames Aeromechanics Branch, Dr. William
Warmbrodt, and Jessica Williams. Special thanks to Christine Gregg and Larry Young for editing and offering
helpful suggestions.
VII Bibliography
Brandt, Gary. July 17, 2013.
Department of Physics, http://van.physics.illinois.edu/qa/listing.php?id=2140. July 17, 2013.
Long, Kurt. July 17, 2013.
NASA, The Coefficient Drag. http://www.grc.nasa.gov/WWW/k-12/rocket/dragco.html. July 29, 2013.
NASA, Rocket Stability. http://exploration.grc.nasa.gov/education/rocket/rktstab.html.July 17, 2013.
NASA, http://www.nasa.gov/. July 15, 2013.
THE PHYSICS HYPERTEXTBOOK, Aerodynamic Drag. http://physics.info/drag/.July 19, 2013.
U.S. DEPARTMENT OF TRANSPORTATION FEDERAL AVAITION ADMINISTRATION.ROTORCRAFT
FLYING HANDBOOK. Washington,DC: 2000. Print.