ME 438 Aerodynamics is a course taught by Dr. Bilal Siddiqui at DHA Suffa University. This set of lectures start from the basic and all the way to aerodynamic coefficients and center of pressure variations with angle of attack.
This document provides an introduction to flight control systems, including:
- A brief history of flight control systems evolving from articulated surfaces to modern fly-by-wire systems.
- An overview of the purpose and basic components of flight control systems, including primary systems for roll, pitch, and yaw control and secondary systems for trim functions.
- Descriptions of the main types of flight control systems - mechanical, hydro-mechanical, and fly-by-wire - and their key characteristics like direct linkage versus electronic signal processing.
- Safety advantages of fly-by-wire systems including increased stability, envelope protection, and integration with auto-pilot functions.
The document reports on a wind tunnel experiment that analyzed the performance of an aerofoil at different angles of attack. Pressure taps on one aerofoil and nylon tufts on another were used to observe stall angles around 14-15.5 degrees. Flow speed and Reynolds number were calculated from pressure measurements. Lift and drag forces were estimated from pressure distributions and found to peak at the stall angle. Blockage ratio and coefficients were plotted against angle of attack, with experimental lift deviating from theory after 15 degrees due to flow separation. The aerofoil was approximated as flat for angles up to 15 degrees.
A wind tunnel is a facility that provides a controlled airflow for testing aerodynamic models. It has a test section where models are placed and sensors measure forces like lift and drag. Wind tunnels are classified based on speed of airflow, air pressure, and size. They can have open or closed designs and use various flow visualization techniques to study airflow patterns.
This document discusses the design and testing of a wind tunnel model to study shock wave boundary layer interactions. Key points:
- A model was designed for testing in CIRA's Scirocco Plasma Wind Tunnel to reproduce conditions from ESA's EXPERT reentry capsule during flight, focusing on interactions over the capsule's flap.
- Numerical simulations were used to help determine the model design and appropriate wind tunnel test conditions.
- The model was tested and measurements compared to numerical predictions, showing reasonable agreement.
- The results will help validate simulations of interactions on the full-scale EXPERT during its planned 2011 flight, completing the methodology of extrapolating ground test results to flight conditions.
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.
This document describes the design of a tri-sonic wind tunnel capable of generating subsonic, transonic, and supersonic flows. It includes the CAD modeling and CFD analysis of nozzle, test section, and diffuser designs for each flow regime. A mechanism for changing the tunnel geometry to achieve the desired flow is also designed and demonstrated. Various tools like MATLAB, ANSYS ICEM CFD, ANSYS FLUENT, and SOLIDWORKS were used. The design aims to allow testing of models in different flow conditions without requiring modification or use of separate tunnels, reducing time and costs. CFD analyses of the individual tunnel sections were performed to validate the designs.
Wind tunnels are used to simulate air flow around vehicles and measure forces, pressure, and heat transfer. There are various types including closed and open return, as well as subsonic, transonic, supersonic, and hypersonic tunnels. Testing involves force measurements, pressure tests, and flow visualization to analyze aerodynamic properties. A variety of instruments are used including force balances, pressure sensors, strain gauges, and laser equipment. Car testing quantifies aerodynamic forces on models to optimize vehicle design parameters. Major wind tunnel facilities are located around the world, with costs ranging from millions to tens of millions of dollars.
ME 438 Aerodynamics is a course taught by Dr. Bilal Siddiqui at DHA Suffa University. This set of lectures start from the basic and all the way to aerodynamic coefficients and center of pressure variations with angle of attack.
This document provides an introduction to flight control systems, including:
- A brief history of flight control systems evolving from articulated surfaces to modern fly-by-wire systems.
- An overview of the purpose and basic components of flight control systems, including primary systems for roll, pitch, and yaw control and secondary systems for trim functions.
- Descriptions of the main types of flight control systems - mechanical, hydro-mechanical, and fly-by-wire - and their key characteristics like direct linkage versus electronic signal processing.
- Safety advantages of fly-by-wire systems including increased stability, envelope protection, and integration with auto-pilot functions.
The document reports on a wind tunnel experiment that analyzed the performance of an aerofoil at different angles of attack. Pressure taps on one aerofoil and nylon tufts on another were used to observe stall angles around 14-15.5 degrees. Flow speed and Reynolds number were calculated from pressure measurements. Lift and drag forces were estimated from pressure distributions and found to peak at the stall angle. Blockage ratio and coefficients were plotted against angle of attack, with experimental lift deviating from theory after 15 degrees due to flow separation. The aerofoil was approximated as flat for angles up to 15 degrees.
A wind tunnel is a facility that provides a controlled airflow for testing aerodynamic models. It has a test section where models are placed and sensors measure forces like lift and drag. Wind tunnels are classified based on speed of airflow, air pressure, and size. They can have open or closed designs and use various flow visualization techniques to study airflow patterns.
This document discusses the design and testing of a wind tunnel model to study shock wave boundary layer interactions. Key points:
- A model was designed for testing in CIRA's Scirocco Plasma Wind Tunnel to reproduce conditions from ESA's EXPERT reentry capsule during flight, focusing on interactions over the capsule's flap.
- Numerical simulations were used to help determine the model design and appropriate wind tunnel test conditions.
- The model was tested and measurements compared to numerical predictions, showing reasonable agreement.
- The results will help validate simulations of interactions on the full-scale EXPERT during its planned 2011 flight, completing the methodology of extrapolating ground test results to flight conditions.
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.
This document describes the design of a tri-sonic wind tunnel capable of generating subsonic, transonic, and supersonic flows. It includes the CAD modeling and CFD analysis of nozzle, test section, and diffuser designs for each flow regime. A mechanism for changing the tunnel geometry to achieve the desired flow is also designed and demonstrated. Various tools like MATLAB, ANSYS ICEM CFD, ANSYS FLUENT, and SOLIDWORKS were used. The design aims to allow testing of models in different flow conditions without requiring modification or use of separate tunnels, reducing time and costs. CFD analyses of the individual tunnel sections were performed to validate the designs.
Wind tunnels are used to simulate air flow around vehicles and measure forces, pressure, and heat transfer. There are various types including closed and open return, as well as subsonic, transonic, supersonic, and hypersonic tunnels. Testing involves force measurements, pressure tests, and flow visualization to analyze aerodynamic properties. A variety of instruments are used including force balances, pressure sensors, strain gauges, and laser equipment. Car testing quantifies aerodynamic forces on models to optimize vehicle design parameters. Major wind tunnel facilities are located around the world, with costs ranging from millions to tens of millions of dollars.
Flight controls allow pilots to control the forces of flight and maneuver aircraft. This chapter focuses on basic flight control systems, from early mechanical systems to modern fly-by-wire designs. It describes the primary flight controls - ailerons, elevators, and rudders - and how they control roll, pitch, and yaw respectively. Adverse yaw created by ailerons is also discussed, as are methods to reduce it like differential ailerons. The chapter provides examples of different flight control configurations for various aircraft types.
The document discusses the design methodology for a subsonic wind tunnel. It involves defining the test section dimensions and desired flow velocity, designing the wind tunnel components like the nozzle, diffusers, settling chamber based on the test section, calculating pressure losses throughout the components, determining overall pressure loss and flow velocity, and selecting appropriate fans to match the design. Key components are the nozzle, diffusers, settling chamber with honeycombs and screens, and corners. Design factors for these include area ratios, lengths, hydraulic diameters, porosity and Reynolds number.
This document summarizes the calibration of a subsonic wind tunnel. Calibration establishes the reliability and accuracy of measurements by comparing the wind tunnel's measurements to a standard. The specifications of the wind tunnel are provided, including a test section size of 600x600x2000 mm and maximum test section velocity of 50 m/s. The calibration procedure involves using a pitot tube connected to a manometer to measure total and static pressure at different fan speeds. These measurements are used to calculate flow velocity and plot a calibration chart comparing flow velocity to motor speed with less than 3% error.
The document provides information about aerodynamics and the four main forces that act on airplanes - lift, weight, thrust, and drag. It explains how the shape of an airfoil generates lift using both Bernoulli's principle of fluid dynamics and Newton's third law of equal and opposite reactions. However, it notes that neither theory fully explains lift and some aspects of each theory have flaws. It also discusses other factors that influence lift such as angle of attack.
The document discusses axial flow turbines. It describes how axial turbines work through multiple stages to convert the kinetic energy of working fluid into power output. It discusses the different types of axial turbine configurations including impulse and reaction turbines. It also describes the analysis of velocity triangles, work and stage dynamics, and turbine blade cascades. Turbine blade cascades are tested in wind tunnels to analyze performance and determine forces like lift and pressure losses.
What are the elements of aircraft performance?
How much thrust do you need?
How fast and how slow can you fly?
#WikiCourses
http://wikicourses.wikispaces.com/Topic+Performance+of+aerospace+vehicles
The document presents a computational fluid dynamics analysis of flow over NACA airfoils using ANSYS Fluent. It describes modeling NACA-4412, NACA-6409, and NACA-0012 airfoils, applying boundary conditions, and analyzing lift, drag, velocity and pressure distributions. The analysis found that NACA-4412 had a higher lift-to-drag ratio than NACA-6409. Additionally, increasing the angle of attack was found to initially increase lift and drag coefficients until a certain point, after which lift decreased while drag continued increasing.
Pressure distribution around a circular cylinder bodies | Fluid Laboratory Saif al-din ali
SAIF ALDIN ALI MADIN
سيف الدين علي ماضي
S96aif@gmail.com
A cylinder in a closed circuit wind tunnel will be experimented upon
to gather the pressure distribution acting on it
Laminar flow is defined when a fluid flows in parallel layers, with no
disruption between the layers. In comparison to this Turbulent flow
has a much more disorganized pattern, it is characterized by
mixing of the fluid by eddies of varying size within the flow.
The Reynolds number (Re), gives the measure for laminar and
turbulent flows. Laminar flow takes place when Reynolds number
is lower than 104, and for Turbulent flow the Re must be greater
than 3Ã-105.
The pressure is measured using the manometer, and then
therefore the pressure at the tapping must be the same as the
pressure head.
The cylinder being experimented on is placed in the wind tunnel.
The pressure upstream of the cylinder is sensed by a taping on the
tunnel wall and is connected to one of the tubes.
This document describes the design and analysis of a small-scale open-loop subsonic wind tunnel and prototype generation. Key aspects include:
- The wind tunnel will be composed of a settling chamber, contraction section, test section, diffuser, and fan to study aerodynamic properties.
- Flow field and drag forces will be measured on 3D printed basic shapes and airfoils, and turbulence intensity will be determined.
- Results from the small-scale wind tunnel are intended to be compatible with practical aerodynamic properties and validate computational fluid dynamics models.
This document discusses aeroelastic flutter analysis. It begins by defining aeroelasticity and describing different aeroelastic phenomena including divergence, flutter, limit cycle oscillations, and vortex shedding. It then discusses Collar's triangle of forces and Garrick's aerothermoelastic tetrahedron models. The document defines flutter as a dangerous vibration phenomenon in structures subjected to aerodynamic forces. It provides examples of different types of flutter and describes predicting flutter in turbomachines. Finally, it summarizes a case study on material mode flutter analysis of laminated curved panels.
This document provides information on basic aerodynamic principles including:
- The four main forces acting on an aeroplane in level flight are lift, weight, thrust, and drag. Lift opposes weight and thrust opposes drag to maintain equilibrium.
- Lift depends on factors like airspeed, air density, wing shape, angle of attack. It can be calculated using a formula involving coefficient of lift.
- Thrust directly opposes drag. Power is the rate of doing work and is the product of thrust and true airspeed.
- Drag has two main components - induced drag from wingtip vortices and profile (parasite) drag from friction and interference. Total drag is the sum
Wind tunnels come in several types depending on their design and airflow characteristics. The document describes blow down, atmospheric entry, high enthalpy, and continuous flow wind tunnels. Continuous flow wind tunnels can be open circuit for subsonic or supersonic testing, or closed circuit. Open circuit tunnels work by drawing in air and exhausting it, while closed circuit wind tunnels recirculate the air through a compressor. The different wind tunnel types are used to simulate various flow conditions for testing aircraft and missile components.
This presentation is about the Fly-By-Wire technology adopted in aircraft systems for greater maneuverability. The mechanical and electronics aspects of this technology is briefed in this presentation.
1. The document introduces the momentum equation for fluids and how it relates the rate of change of momentum within a control volume to the forces acting on the fluid.
2. Examples are provided to demonstrate how the momentum equation can be used to calculate forces exerted on surfaces by flowing fluids, such as the force of a jet on a flat plate or the force on a curved vane that deflects a fluid flow.
3. Euler's equation relating pressure, velocity, elevation, and density along a streamline is derived from applying Newton's second law to an infinitesimal element of fluid.
This document provides an overview of Schlieren flow visualization technique. It discusses that Schlieren photography uses the refractive index variations in a flow field to visualize density gradients. The conventional Schlieren system uses a light source, knife edge, and camera to capture displaced images caused by differences in light refraction through the test section. The document also briefly compares Schlieren to other flow visualization methods like shadowgraph, and provides examples of Schlieren used to photograph aircraft shockwaves in flight testing.
- The document is a seminar paper on aircraft drag reduction techniques presented by Dhanashree M. Waghmare and guided by Prof. V. A. Yevalikar. It includes sections on literature review, aims and objectives, introduction to basic aerodynamic principles, aircraft wing terminology, forces on aircraft, types of drag, factors affecting drag, and methods to reduce drag. The paper discusses drag reduction techniques like increasing wing aspect ratio, wing tip devices, vortex generators, and laminar flow control. It concludes with future areas of research like friction drag reduction at supersonic speeds and circulation control using auxiliary power.
Artificial feel systems in aircraft provide pilots with feedback about control surface positions and aerodynamic loads without direct mechanical linkage. They use springs or dynamic air pressure differentials to create resistance proportional to pilot control inputs and airspeed. Modern aircraft use spring or Q feel systems, with Q feel employing a piston or hydraulic actuator biased by pitot-static differential pressure to generate opposing forces on controls.
This document discusses various airfoils used for horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). It provides details on the NREL S819, NACA 23012, and DU 06-W-200 airfoils, including their maximum thickness, camber, and location on the chord. It also mentions the NACA 66-018 airfoil and describes the materials commonly used to manufacture wind turbine blades, such as glass and carbon fabrics, foam cores, epoxy resins, and protective paint coatings. In addition, it notes that the blade twist allows for an optimal angle of attack along the blade from root to tip to maximize energy extraction from the wind.
The document describes different types of wind tunnels and their components. It discusses wind tunnels classified by air velocity as subsonic, supersonic, hypersonic, or transonic. It also describes open and closed circuit wind tunnels. The key components of wind tunnels are then outlined as the settling chamber, contraction cone, test section, diffuser, and drive section. Examples and purposes of each component are provided.
This document provides an overview of aeroelasticity, including its history, classifications, and precautions. It discusses how aeroelasticity studies the interaction between inertial, structural and aerodynamic forces. The document outlines the necessity of studying aeroelasticity effects for rotor design, wind energy, and to understand catastrophic failures. It then describes different types of static and dynamic aeroelasticity like divergence, control reversal, flutter, buffeting, and transonic phenomena. Precautions like testing and analysis are discussed.
Wind Tunnel Based Anemometer Testing FacilityBenson Gilbert
This document describes the development of a wind tunnel facility at the University of California, Davis for calibrating anemometers. The author upgraded the existing wind tunnel and data acquisition systems to automatically calibrate anemometers using a LabVIEW virtual instrument. The calibration method involves measuring wind speed from a reference anemometer and the test anemometer at various wind tunnel fan speeds to generate a calibration curve and determine the measurement uncertainty of the system. The upgraded facility provides an accurate means of calibrating anemometers to help assess wind energy resources.
The document describes an experiment to determine the tensile strength of glass fiber composites with different volume compositions (35/65, 45/55, 55/45). Specimens were prepared with the compositions and tested using a universal tensile machine. Results showed the 45/55 composition had the highest average tensile strength and Young's modulus, indicating it is the best composition. In conclusion, the mechanical properties of fiber composites depend on the optimal volume composition of fiber and matrix.
Flight controls allow pilots to control the forces of flight and maneuver aircraft. This chapter focuses on basic flight control systems, from early mechanical systems to modern fly-by-wire designs. It describes the primary flight controls - ailerons, elevators, and rudders - and how they control roll, pitch, and yaw respectively. Adverse yaw created by ailerons is also discussed, as are methods to reduce it like differential ailerons. The chapter provides examples of different flight control configurations for various aircraft types.
The document discusses the design methodology for a subsonic wind tunnel. It involves defining the test section dimensions and desired flow velocity, designing the wind tunnel components like the nozzle, diffusers, settling chamber based on the test section, calculating pressure losses throughout the components, determining overall pressure loss and flow velocity, and selecting appropriate fans to match the design. Key components are the nozzle, diffusers, settling chamber with honeycombs and screens, and corners. Design factors for these include area ratios, lengths, hydraulic diameters, porosity and Reynolds number.
This document summarizes the calibration of a subsonic wind tunnel. Calibration establishes the reliability and accuracy of measurements by comparing the wind tunnel's measurements to a standard. The specifications of the wind tunnel are provided, including a test section size of 600x600x2000 mm and maximum test section velocity of 50 m/s. The calibration procedure involves using a pitot tube connected to a manometer to measure total and static pressure at different fan speeds. These measurements are used to calculate flow velocity and plot a calibration chart comparing flow velocity to motor speed with less than 3% error.
The document provides information about aerodynamics and the four main forces that act on airplanes - lift, weight, thrust, and drag. It explains how the shape of an airfoil generates lift using both Bernoulli's principle of fluid dynamics and Newton's third law of equal and opposite reactions. However, it notes that neither theory fully explains lift and some aspects of each theory have flaws. It also discusses other factors that influence lift such as angle of attack.
The document discusses axial flow turbines. It describes how axial turbines work through multiple stages to convert the kinetic energy of working fluid into power output. It discusses the different types of axial turbine configurations including impulse and reaction turbines. It also describes the analysis of velocity triangles, work and stage dynamics, and turbine blade cascades. Turbine blade cascades are tested in wind tunnels to analyze performance and determine forces like lift and pressure losses.
What are the elements of aircraft performance?
How much thrust do you need?
How fast and how slow can you fly?
#WikiCourses
http://wikicourses.wikispaces.com/Topic+Performance+of+aerospace+vehicles
The document presents a computational fluid dynamics analysis of flow over NACA airfoils using ANSYS Fluent. It describes modeling NACA-4412, NACA-6409, and NACA-0012 airfoils, applying boundary conditions, and analyzing lift, drag, velocity and pressure distributions. The analysis found that NACA-4412 had a higher lift-to-drag ratio than NACA-6409. Additionally, increasing the angle of attack was found to initially increase lift and drag coefficients until a certain point, after which lift decreased while drag continued increasing.
Pressure distribution around a circular cylinder bodies | Fluid Laboratory Saif al-din ali
SAIF ALDIN ALI MADIN
سيف الدين علي ماضي
S96aif@gmail.com
A cylinder in a closed circuit wind tunnel will be experimented upon
to gather the pressure distribution acting on it
Laminar flow is defined when a fluid flows in parallel layers, with no
disruption between the layers. In comparison to this Turbulent flow
has a much more disorganized pattern, it is characterized by
mixing of the fluid by eddies of varying size within the flow.
The Reynolds number (Re), gives the measure for laminar and
turbulent flows. Laminar flow takes place when Reynolds number
is lower than 104, and for Turbulent flow the Re must be greater
than 3Ã-105.
The pressure is measured using the manometer, and then
therefore the pressure at the tapping must be the same as the
pressure head.
The cylinder being experimented on is placed in the wind tunnel.
The pressure upstream of the cylinder is sensed by a taping on the
tunnel wall and is connected to one of the tubes.
This document describes the design and analysis of a small-scale open-loop subsonic wind tunnel and prototype generation. Key aspects include:
- The wind tunnel will be composed of a settling chamber, contraction section, test section, diffuser, and fan to study aerodynamic properties.
- Flow field and drag forces will be measured on 3D printed basic shapes and airfoils, and turbulence intensity will be determined.
- Results from the small-scale wind tunnel are intended to be compatible with practical aerodynamic properties and validate computational fluid dynamics models.
This document discusses aeroelastic flutter analysis. It begins by defining aeroelasticity and describing different aeroelastic phenomena including divergence, flutter, limit cycle oscillations, and vortex shedding. It then discusses Collar's triangle of forces and Garrick's aerothermoelastic tetrahedron models. The document defines flutter as a dangerous vibration phenomenon in structures subjected to aerodynamic forces. It provides examples of different types of flutter and describes predicting flutter in turbomachines. Finally, it summarizes a case study on material mode flutter analysis of laminated curved panels.
This document provides information on basic aerodynamic principles including:
- The four main forces acting on an aeroplane in level flight are lift, weight, thrust, and drag. Lift opposes weight and thrust opposes drag to maintain equilibrium.
- Lift depends on factors like airspeed, air density, wing shape, angle of attack. It can be calculated using a formula involving coefficient of lift.
- Thrust directly opposes drag. Power is the rate of doing work and is the product of thrust and true airspeed.
- Drag has two main components - induced drag from wingtip vortices and profile (parasite) drag from friction and interference. Total drag is the sum
Wind tunnels come in several types depending on their design and airflow characteristics. The document describes blow down, atmospheric entry, high enthalpy, and continuous flow wind tunnels. Continuous flow wind tunnels can be open circuit for subsonic or supersonic testing, or closed circuit. Open circuit tunnels work by drawing in air and exhausting it, while closed circuit wind tunnels recirculate the air through a compressor. The different wind tunnel types are used to simulate various flow conditions for testing aircraft and missile components.
This presentation is about the Fly-By-Wire technology adopted in aircraft systems for greater maneuverability. The mechanical and electronics aspects of this technology is briefed in this presentation.
1. The document introduces the momentum equation for fluids and how it relates the rate of change of momentum within a control volume to the forces acting on the fluid.
2. Examples are provided to demonstrate how the momentum equation can be used to calculate forces exerted on surfaces by flowing fluids, such as the force of a jet on a flat plate or the force on a curved vane that deflects a fluid flow.
3. Euler's equation relating pressure, velocity, elevation, and density along a streamline is derived from applying Newton's second law to an infinitesimal element of fluid.
This document provides an overview of Schlieren flow visualization technique. It discusses that Schlieren photography uses the refractive index variations in a flow field to visualize density gradients. The conventional Schlieren system uses a light source, knife edge, and camera to capture displaced images caused by differences in light refraction through the test section. The document also briefly compares Schlieren to other flow visualization methods like shadowgraph, and provides examples of Schlieren used to photograph aircraft shockwaves in flight testing.
- The document is a seminar paper on aircraft drag reduction techniques presented by Dhanashree M. Waghmare and guided by Prof. V. A. Yevalikar. It includes sections on literature review, aims and objectives, introduction to basic aerodynamic principles, aircraft wing terminology, forces on aircraft, types of drag, factors affecting drag, and methods to reduce drag. The paper discusses drag reduction techniques like increasing wing aspect ratio, wing tip devices, vortex generators, and laminar flow control. It concludes with future areas of research like friction drag reduction at supersonic speeds and circulation control using auxiliary power.
Artificial feel systems in aircraft provide pilots with feedback about control surface positions and aerodynamic loads without direct mechanical linkage. They use springs or dynamic air pressure differentials to create resistance proportional to pilot control inputs and airspeed. Modern aircraft use spring or Q feel systems, with Q feel employing a piston or hydraulic actuator biased by pitot-static differential pressure to generate opposing forces on controls.
This document discusses various airfoils used for horizontal axis wind turbines (HAWT) and vertical axis wind turbines (VAWT). It provides details on the NREL S819, NACA 23012, and DU 06-W-200 airfoils, including their maximum thickness, camber, and location on the chord. It also mentions the NACA 66-018 airfoil and describes the materials commonly used to manufacture wind turbine blades, such as glass and carbon fabrics, foam cores, epoxy resins, and protective paint coatings. In addition, it notes that the blade twist allows for an optimal angle of attack along the blade from root to tip to maximize energy extraction from the wind.
The document describes different types of wind tunnels and their components. It discusses wind tunnels classified by air velocity as subsonic, supersonic, hypersonic, or transonic. It also describes open and closed circuit wind tunnels. The key components of wind tunnels are then outlined as the settling chamber, contraction cone, test section, diffuser, and drive section. Examples and purposes of each component are provided.
This document provides an overview of aeroelasticity, including its history, classifications, and precautions. It discusses how aeroelasticity studies the interaction between inertial, structural and aerodynamic forces. The document outlines the necessity of studying aeroelasticity effects for rotor design, wind energy, and to understand catastrophic failures. It then describes different types of static and dynamic aeroelasticity like divergence, control reversal, flutter, buffeting, and transonic phenomena. Precautions like testing and analysis are discussed.
Wind Tunnel Based Anemometer Testing FacilityBenson Gilbert
This document describes the development of a wind tunnel facility at the University of California, Davis for calibrating anemometers. The author upgraded the existing wind tunnel and data acquisition systems to automatically calibrate anemometers using a LabVIEW virtual instrument. The calibration method involves measuring wind speed from a reference anemometer and the test anemometer at various wind tunnel fan speeds to generate a calibration curve and determine the measurement uncertainty of the system. The upgraded facility provides an accurate means of calibrating anemometers to help assess wind energy resources.
The document describes an experiment to determine the tensile strength of glass fiber composites with different volume compositions (35/65, 45/55, 55/45). Specimens were prepared with the compositions and tested using a universal tensile machine. Results showed the 45/55 composition had the highest average tensile strength and Young's modulus, indicating it is the best composition. In conclusion, the mechanical properties of fiber composites depend on the optimal volume composition of fiber and matrix.
This document discusses various methods for measuring cyclist aerodynamics without using a wind tunnel. It describes taking photographs to measure frontal area, coast-down testing on hills or tracks to determine drag coefficients, and steady-speed power meter methods to differentiate aerodynamic drag and rolling resistance. It provides examples of using these field methods on cyclists and compares the results to wind tunnel data. Specifically, frontal area photography found a mean drag coefficient of 0.707, while coast-down and power meter regression analyses estimated drag values within 1% of wind tunnel tests.
This document discusses shock waves. It defines shock waves as thin regions where supersonic flow is rapidly decelerated to subsonic flow through an adiabatic but non-isentropic process. There are three types of shock waves discussed: normal shock waves, which are perpendicular to flow; oblique shock waves, which are at an angle to flow; and curved shock waves. Examples of normal shock wave formation and oblique shock wave applications in aircraft are provided. Over-expanded and under-expanded flows through converging-diverging ducts are also summarized.
The document proposes the design of a low-speed subsonic wind tunnel to measure aerodynamic forces and enhance understanding of aerodynamic design. The wind tunnel would have an open or closed loop, and aims to allow students to learn and companies to test commercial designs on a laboratory test bench. It would be limited to low speeds and have a limited test section. The design plans to control angle of attack, measure airspeed and pressure, and display results on a computer using data from sensors. The methodology involves designing the tunnel structure, models, and software before testing and evaluating airspeed calculations, pressure measurements, and angle of attack displays.
On pairs of Special Polygonal numbers with Unit differenceIJMER
This document presents formulas to determine the ranks of different polygonal numbers (e.g. triangular, hexagonal, etc.) where the difference between any two numbers is unity. Explicit formulas with recurrence relations are given for the ranks of centered hexagonal-triangular, centered heptagonal-triangular, and other pairs of polygonal numbers with a unit difference. The ranks are expressed using generalized solutions to Pell-type equations.
This document summarizes a strategy for choosing optimal process parameters for operating a nutrient mist reactor to grow hairy roots. It presents a theoretical model and numerical simulations.
The model describes the evolution of liquid holdup and nutrient concentration in the root bed under intermittent misting cycles. Guidelines are provided for selecting the feed concentration, flow rate, and durations of mist-ON and mist-OFF cycles. Numerical simulations show that the reactor can be run with very low cumulative mist-ON duration (e.g. 10% of total time) while keeping the mist-OFF for most of the time (e.g. 90%), to prevent nutrient deficiency or waterlogging in the root bed. The optimal durations of misting cycles depend on
Seismic Behavior of Two Layers of Drum And Up To the Mouth of the Mouth Dept...IJMER
This document summarizes a study on the seismic behavior of two-layer drum structures with varying deflection to span ratios and depths to the mouth. Finite element analysis was conducted using ANSYS software to analyze models with different geometric properties under dead and live loads as well as earthquake loads. Modal analysis was performed to determine natural frequencies and period. Dynamic time history analysis found that increasing the depth to the mouth increases the period of the structure. Buckling behavior was also investigated, with some models experiencing buckling of members during seismic loading. The study provides data on the steel weights, natural frequencies, displacements, and buckling of members for different drum structure configurations.
This document reviews techniques used in spoken-word recognition systems. It discusses popular feature extraction techniques like MFCC, LPC, DWT, WPD that are used to represent speech signals in a compact form before classification. Classification techniques discussed are ANN, HMM, DTW, and VQ. The document provides a brief overview of each technique and their advantages. It also presents the generalized workflow of a spoken-word recognition system including stages of speech acquisition, pre-emphasis, feature extraction, modeling, classification, and output of recognized text.
Information Communication Technology: Practices for AcademiaIJMER
The document discusses the role of information and communication technology (ICT) in academia. It outlines several challenges facing the current educational system, including issues with teaching, learning, assessment, and service delivery. The document then explores how ICT can help address these challenges through tools like cognitive tutors, simulation-based teaching, and online assessment systems. It concludes by recommending increased ICT integration, infrastructure development, training, and public-private partnerships to maximize the benefits of technology for education.
This document summarizes a research paper about using a Z-Source Inverter (ZSI) based STATCOM to enhance power quality in a thirty bus power system. It first provides background on power quality issues and how Flexible AC Transmission Systems (FACTS) devices like STATCOMs can help address them. It then describes the components and operation of a conventional STATCOM and introduces the ZSI as an alternative inverter topology. The research presented in the paper models and simulates a thirty bus system both with and without a ZSI-based STATCOM to study improvements in voltage regulation and reactive power compensation.
This document discusses the computational fluid dynamics (CFD) analysis of flow through a butterfly valve. It aims to determine the head loss coefficient and flow coefficient for the valve at different opening angles (30°, 60°, 75°, 90°). The CFD software ANSYS ICEM was used to model the valve geometry and ANSYS CFX was used to simulate the flow. The results found that the velocity increased with opening angle while head loss coefficient decreased. Streamlines became more uniform at higher openings. Numerical results closely matched experimental data, validating the CFD analysis method. The study provides a less expensive and time-consuming alternative to experimental testing of large butterfly valves.
Area Efficient and high-speed fir filter implementation using divided LUT methodIJMER
Traditional method of implementing FIR filters costs considerable hardware resourses,
which goes against the decrease of circuit scale and the increase of system speed. A new design and
implementation of FIR filters using Distributed Arithmetic is provided in this paper to slove this
problem. Distributed Arithmetic structure is used to increase the resourse useage while pipeline
structure is also used to increase the system speed. In addition, the devided LUT method is also used to
decrease the required memory units. The simulation results indicate that FIR filters using Distributed
Arithmetic can work stable with high speed and can save almost 50 percent hardware resourses to
decrease the circuit scale, and can be applied to a variety of areas for its great flexibility and high
reliability
The document provides guidelines for assessing lifting, lowering, pushing, pulling and carrying tasks using tables developed by Liberty Mutual based on research conducted by Drs. Stover Snook and Vincent Ciriello. The tables provide population percentages for what percentage of workers can perform certain manual handling tasks based on measurements of weights, distances, heights and frequencies. The tables are intended to help identify risk factors for injury and inform cost-effective ergonomic solutions. Training is recommended for properly using the tables to conduct task analyses and measurements. [END SUMMARY]
Wavelet Based Analysis of Online Monitoring of Electrical Power by Mobile Tec...IJMER
Electrical automation is an important option for obtaining optimal solution while monitoring the electrical power consumption. While using the conventional methods the errors in continuous monitoring of power consumption is more. But the system requires not only the monitoring of the energy but also requires the analysis of the monitored energy. In this paper wavelet analysis is used for the analysis of the monitored energy/power which is monitored by GPRS technology. By using the GPRS mobile technology the energy consumption is monitored continuously and the observed data is interfaced to the computer by RS 232 port. By using MATLAB the monitored data is processed to obtain in depth analysis of the monitored power. The proposed method not only monitors the data but also provides efficient means to analyze the observed data by Wavelet Transform
This document summarizes and compares two maximum power point tracking (MPPT) techniques for photovoltaic systems: perturbation and observation (P&O) and improved perturbation and observation (IP&O). P&O is commonly used due to its simplicity but has drawbacks like slow response and oscillations around the maximum power point. IP&O aims to overcome these issues by automatically adjusting the perturbation step size and hysteresis band. Simulation results show IP&O increases total PV output power by 0.5% compared to P&O under changing weather conditions and has faster tracking response and higher reliability.
The document summarizes the European Women Interactive Learning (EWIL) project. The EWIL project aims to stimulate women's motivation to learn and raise the quality of education opportunities for women in non-formal contexts. Specifically, the project aims to allow women to acquire ICT knowledge, promote women's participation in adult learning using culturally relevant content, and help women maximize their ICT skills for personal and professional use. The project receives funding from the Lifelong Learning Programme of the European Union.
Variant High Origin of the Posterior Tibial ArteryIJMER
1. The document describes an anatomical variation observed during a routine cadaver dissection where the posterior tibial artery originated from the popliteal artery proximal to the popliteus muscle.
2. This variation is important for orthopaedic surgeons, radiologists, and others to be aware of to minimize risks during knee surgeries and angiographic studies.
3. The authors conclude that variations in the branching pattern of the popliteal artery are common and need to be considered during related surgical and medical interventions.
This document contains a list of vocabulary words that could appear on the SAT exam. Some of the words in the list include revert, procrastinate, interminable, servile, fickle, pious, assimilate, amorphous, virulent, anarchy, transient, callow, desist, refute, extemporaneous, antiquate, waive, intermittent, supplant, and alchemy.
Design and Fabrication of Subsonic Wind TunnelIJMERJOURNAL
The document describes the design and fabrication of a subsonic wind tunnel. It discusses how wind tunnels are used to study aerodynamics of objects by moving air past stationary models. The constructed wind tunnel consists of a contraction cone, test section, and diffuser. Aerodynamic forces and drag were measured on scaled vehicle models placed in the test section. The wind tunnel was found to efficiently test aerodynamics and calculate drag, allowing more efficient vehicle design. Future work may include testing airfoils and pressure variations on obstructions.
IRJET- Design and Fabrication of an Open Circuit Subsonic Wind Tunnel for Edu...IRJET Journal
This document describes the design and fabrication of a low-cost subsonic wind tunnel for educational purposes. Key aspects include:
1) The wind tunnel was designed and built by students and a professor to support fluid mechanics experiments at their university on a limited budget.
2) Design considerations included achieving a test section air speed over 10m/s, compact size, ease of use, and longevity.
3) Components like the contraction cone, diffuser, test section, and flow conditioner were designed and fabricated based on guidelines from literature.
4) Experimental testing showed average air speeds in the test section of 12.9m/s, with variations within 1m/s. CFD simulation
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
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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.
This document describes a study on the uniformity of pressure profiles in a wind tunnel. It begins with background information on the development of wind tunnels. It then describes the experimental setup of the uni-insta's wind tunnel, which features a bell mouth entry, honeycomb settling chamber, and acrylic working section. Pressure measurements were taken at six points in the working section using a probe and manometer. Graphs of the pressure readings show the pressure distribution was nearly uniform, with small variations between the five static pressure ports. The document concludes the wind tunnel achieved good simulation of atmospheric boundary layers and uniform flow.
Analysis of wings using Airfoil NACA 4412 at different angle of attackIJMER
This document summarizes wind tunnel testing of the NACA 4412 airfoil at different angles of attack. The testing was conducted to analyze lift and drag forces on the airfoil at varying angles. The results found that lift increases with angle of attack until a maximum is reached, after which drag becomes dominant and stall occurs. Graphs and tables presented in the document compare experimental pressure and friction coefficient data from the wind tunnel tests to computational fluid dynamics simulations using different turbulence models. The models were able to accurately predict flow separation locations and other characteristics.
This document provides information about wind tunnels. It begins with an introduction that defines a wind tunnel as an aerodynamic device used to test how air flows around objects. It then discusses the history and present use of wind tunnels. The working principle, classifications, components, advantages, disadvantages, and calculations involved in wind tunnels are described. Conclusions state that wind tunnel results may differ from real-world conditions due to boundary layer effects. References are provided at the end.
This document summarizes an experimental study that investigated the effect of multiple wings on lift and drag forces. Researchers constructed a model with three symmetric airfoils spaced 12cm apart and tested it in a wind tunnel at various angles of attack up to 20 degrees. Results showed that lift and pressure coefficients generally increased with angle of attack for each airfoil, while drag coefficient slightly decreased. The multiple wing configuration was found to increase lift compared to a single airfoil.
IRJET- Design, Manufacturing and Testing of Open-Circuit Subsonic Wind Tunnel...IRJET Journal
This document provides a comprehensive review of the design, manufacturing, and testing of open-circuit subsonic wind tunnels. It discusses key components like the test section, contraction cone, diffuser, and drive system. For the settling chamber and honeycomb structure, the document recommends a length 5-10 times the diameter to reduce lateral turbulence, and notes hexagonal cells have the lowest pressure drop. It states the contraction ratio should be between 7-12 for optimum performance to eliminate axial flow fluctuations. The document also categorizes wind tunnels as open-circuit or closed-circuit, and describes classifications based on airflow speed like subsonic, transonic, supersonic, and hypersonic.
Applications of Circulation Control, Yesterday and TodayCSCJournals
Circulation control, an aerodynamic method of changing the properties of an airfoil, such as lift, camber and angle of attack, has been used in several unique ways since its inception, as an enhancement to fixed wing aircraft, in the 1960’s. Early in the research venture, this technology was used on the main wing of an aircraft in conjunction with a Coandă surface, such as a rounded trailing edge or a deployable flap. Research during this time proved to be the foundation of the circulation control technology and showed that small amounts of exit jet velocity could have a large impact on the aerodynamics of an airfoil. In the 1970’s the inspirations that drove circulation control research changed from design work to optimization of the parameters which were found to have the most effect on circulation control. These studies included slot placement, favorable momentum coefficient, and pressurization benefits and determents. This research period also allowed for expansion of the uses of circulation control to submarine/hydrodynamic and rotary wing applications. Newest research has brought on several propeller driven applications and the recent push for efficient renewable research has allowed circulation control research technologies to evolve into use in wind turbine and water turbine applications. The idea being that with circulation control the turbine can adapt easier to the changing wind velocity and direction and ultimately capture more power than an un-augmented turbine. As with most new and novel technologies there is a process and time delay associated with their development and ultimate application. For some technologies the market, or the supporting hardware, are lacking and sometimes the technology has strong advocacies for yet to be fulfilled expectations. In most of these cases a strong idea will re-surface repeatedly until the art has matured, or the better solution is found. This paper will focus on the previously developed circulation control research, from its beginnings, as used on fixed wing aircraft, following the progression, as this technology evolved through the past five decades, to its now more widely considered potential.
The document summarizes an experimental study that investigated the wind load on hexagonal cylinders. Static pressure distributions were measured on single and paired hexagonal cylinders in a wind tunnel at various wind speeds and angles of attack. Lower drag and lift forces were observed for hexagonal cylinders compared to square cylinders, approaching the lower values seen for circular cylinders. It was concluded that hexagonal cylinders experience significantly lower wind loads than square cylinders of the same width.
Wind tunnel experiments were conducted on origami-inspired building models to understand wind flow patterns. The experiments found that a compressed, spherical model had wind flow mostly over it, creating pressure zones. A flexible, spread-out model had uniform wind flow throughout its surfaces. A vertically oriented, twisted model allowed wind to pass through it without accumulating at the base, making it more aerodynamic. The spread-out and twisted models were determined to be the most stable configurations for an origami-inspired building and tower, respectively, as they avoided concentrating wind forces.
This is my first crack at writing a technical report for an assignment in a mechanical engineering course at the University of Alberta. How was the clarity? Any feedback on how I can improve?
A Study of Wind Turbine Blade Power Enhancement Using Aerodynamic Properties IJMER
Technological advancements have improvised them over time. In this paper we shall glance at
the features. Wind energy is the most popular renewable energy. In order to increase the use of wind
energy, it is important to develop wind turbine rotor models with high rotation rates and power
coefficients. These elemental forces are summed along the span of the blade to calculate the total forces
and moments exerted on the turbine. This study aimed at manufacturing highly efficient wind turbine
rotor models using NACA profiles.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
1) The document describes an experimental study on the aerodynamic characteristics of basic airfoils at low Reynolds numbers between 2.9×104 and 7.2×104.
2) Wind tunnel experiments were conducted on airfoil models including a NACA0015, flat plate, and modified flat plates with different leading and trailing edge geometries. Surface pressure measurements were taken at varying angles of attack.
3) Preliminary results showed the importance of sharp leading edges for low Reynolds number flight and the influence of airfoil geometry on aerodynamic characteristics like pressure coefficient.
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
The papers for publication in The International Journal of Engineering& Science are selected through rigorous peer reviews to ensure originality, timeliness, relevance, and readability.
Experimental study of aerodynamic characteristics of airfoils usingrubiat mustak
This document presents an experimental study on modifying airfoil surfaces with dimples of different shapes to observe changes in aerodynamic characteristics. The study will construct models of an NACA 4415 airfoil profile with outward and inward dimples. Wind tunnel experiments will measure coefficients of lift, drag, and moment as well as lift-to-drag ratio. The objective is to see how dimple shapes affect an airfoil's aerodynamic performance. The work plan outlines construction of airfoil models, wind tunnel testing, and data analysis over a period of several weeks.
The Hydrodynamic Performance Examination of a New Floating Breakwater Configu...IJAEMSJORNAL
It is critical to protect coastal and offshore structures. Most current studies and scientific investigations are centered on how to protect seashore with an efficient and cost-effective system. This study involved the testing of a new floating breakwater configuration (FB). A series of experiments were carried out in the lab of The Higher Institute of Engineering (El-shorouk City) on the new model and the traditional vertical plane FB without a curved face to compare their behaviours and performance in wave attenuation. The incident, reflected, and transmitted wave heights were measured, and the coefficients of reflection, transmission, and energy dissipation were calculated using these measurements. In terms of hydrodynamic performance, the curved-face floating breakwater outperformed the traditional vertical floating breakwater, according to the study's highlights. The curved face model significantly reduced wave transmission values when compared to the traditional vertical configuration. The greater the concavity of the curve, the better the model handles waves, especially when the wave steepness is low.
This document describes a numerical investigation of the aerodynamic performance of a Darrieus vertical axis wind turbine with and without a barrier arrangement. A barrier was designed to be placed in front of the rotor to increase performance by preventing negative torque. Computational fluid dynamics simulations were performed using Ansys Fluent software to analyze the rotor's power performance with and without the barrier. The results showed that the rotor configuration with the barrier produced higher performance coefficients than the configuration without a barrier.
Similar to Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open Circuit Wind Tunnel Model (20)
A Study on Translucent Concrete Product and Its Properties by Using Optical F...IJMER
- Translucent concrete is a concrete based material with light-transferring properties,
obtained due to embedded light optical elements like Optical fibers used in concrete. Light is conducted
through the concrete from one end to the other. This results into a certain light pattern on the other
surface, depending on the fiber structure. Optical fibers transmit light so effectively that there is
virtually no loss of light conducted through the fibers. This paper deals with the modeling of such
translucent or transparent concrete blocks and panel and their usage and also the advantages it brings
in the field. The main purpose is to use sunlight as a light source to reduce the power consumption of
illumination and to use the optical fiber to sense the stress of structures and also use this concrete as an
architectural purpose of the building
Developing Cost Effective Automation for Cotton Seed DelintingIJMER
A low cost automation system for removal of lint from cottonseed is to be designed and
developed. The setup consists of stainless steel drum with stirrer in which cottonseeds having lint is mixed
with concentrated sulphuric acid. So lint will get burn. This lint free cottonseed treated with lime water to
neutralize acidic nature. After water washing this cottonseeds are used for agriculter purpose
Study & Testing Of Bio-Composite Material Based On Munja FibreIJMER
The incorporation of natural fibres such as munja fiber composites has gained
increasing applications both in many areas of Engineering and Technology. The aim of this study is to
evaluate mechanical properties such as flexural and tensile properties of reinforced epoxy composites.
This is mainly due to their applicable benefits as they are light weight and offer low cost compared to
synthetic fibre composites. Munja fibres recently have been a substitute material in many weight-critical
applications in areas such as aerospace, automotive and other high demanding industrial sectors. In
this study, natural munja fibre composites and munja/fibreglass hybrid composites were fabricated by a
combination of hand lay-up and cold-press methods. A new variety in munja fibre is the present work
the main aim of the work is to extract the neat fibre and is characterized for its flexural characteristics.
The composites are fabricated by reinforcing untreated and treated fibre and are tested for their
mechanical, properties strictly as per ASTM procedures.
Hybrid Engine (Stirling Engine + IC Engine + Electric Motor)IJMER
Hybrid engine is a combination of Stirling engine, IC engine and Electric motor. All these 3 are
connected together to a single shaft. The power source of the Stirling engine will be a Solar Panel. The aim of
this is to run the automobile using a Hybrid engine
Fabrication & Characterization of Bio Composite Materials Based On Sunnhemp F...IJMER
This document summarizes research on the fabrication and characterization of bio-composite materials using sunnhemp fibre. The document discusses how sunnhemp fibre was used to reinforce an epoxy matrix through hand lay-up methods. Various mechanical properties of the bio-composites were tested, including tensile, flexural, and impact properties. The results of the mechanical tests on the bio-composite specimens are presented. Potential applications of the sunnhemp fibre bio-composites are also suggested, such as in fall ceilings, partitions, packaging, automotive interiors, and toys.
Geochemistry and Genesis of Kammatturu Iron Ores of Devagiri Formation, Sandu...IJMER
The Greenstone belts of Karnataka are enriched in BIFs in Dharwar craton, where Iron
formations are confined to the basin shelf, clearly separated from the deeper-water iron formation that
accumulated at the basin margin and flanking the marine basin. Geochemical data procured in terms of
major, trace and REE are plotted in various diagrams to interpret the genesis of BIFs. Al2O3, Fe2O3 (T),
TiO2, CaO, and SiO2 abundances and ratios show a wide variation. Ni, Co, Zr, Sc, V, Rb, Sr, U, Th,
ΣREE, La, Ce and Eu anomalies and their binary relationships indicate that wherever the terrigenous
component has increased, the concentration of elements of felsic such as Zr and Hf has gone up. Elevated
concentrations of Ni, Co and Sc are contributed by chlorite and other components characteristic of basic
volcanic debris. The data suggest that these formations were generated by chemical and clastic
sedimentary processes on a shallow shelf. During transgression, chemical precipitation took place at the
sediment-water interface, whereas at the time of regression. Iron ore formed with sedimentary structures
and textures in Kammatturu area, in a setting where the water column was oxygenated.
Experimental Investigation on Characteristic Study of the Carbon Steel C45 in...IJMER
In this paper, the mechanical characteristics of C45 medium carbon steel are investigated
under various working conditions. The main characteristic to be studied on this paper is impact toughness
of the material with different configurations and the experiment were carried out on charpy impact testing
equipment. This study reveals the ability of the material to absorb energy up to failure for various
specimen configurations under different heat treated conditions and the corresponding results were
compared with the analysis outcome
Non linear analysis of Robot Gun Support Structure using Equivalent Dynamic A...IJMER
Robot guns are being increasingly employed in automotive manufacturing to replace
risky jobs and also to increase productivity. Using a single robot for a single operation proves to be
expensive. Hence for cost optimization, multiple guns are mounted on a single robot and multiple
operations are performed. Robot Gun structure is an efficient way in which multiple welds can be done
simultaneously. However mounting several weld guns on a single structure induces a variety of
dynamic loads, especially during movement of the robot arm as it maneuvers to reach the weld
locations. The primary idea employed in this paper, is to model those dynamic loads as equivalent G
force loads in FEA. This approach will be on the conservative side, and will be saving time and
subsequently cost efficient. The approach of the paper is towards creating a standard operating
procedure when it comes to analysis of such structures, with emphasis on deploying various technical
aspects of FEA such as Non Linear Geometry, Multipoint Constraint Contact Algorithm, Multizone
meshing .
Static Analysis of Go-Kart Chassis by Analytical and Solid Works SimulationIJMER
This paper aims to do modelling, simulation and performing the static analysis of a go
kart chassis consisting of Circular beams. Modelling, simulations and analysis are performed using 3-D
modelling software i.e. Solid Works and ANSYS according to the rulebook provided by Indian Society of
New Era Engineers (ISNEE) for National Go Kart Championship (NGKC-14).The maximum deflection is
determined by performing static analysis. Computed results are then compared to analytical calculation,
where it is found that the location of maximum deflection agrees well with theoretical approximation but
varies on magnitude aspect.
In récent year various vehicle introduced in market but due to limitation in
carbon émission and BS Séries limitd speed availability vehicle in the market and causing of
environnent pollution over few year There is need to decrease dependancy on fuel vehicle.
bicycle is to be modified for optional in the future To implement new technique using change in
pedal assembly and variable speed gearbox such as planetary gear optimise speed of vehicle
with variable speed ratio.To increase the efficiency of bicycle for confortable drive and to
reduce torque appli éd on bicycle. we introduced epicyclic gear box in which transmission done
throgh Chain Drive (i.e. Sprocket )to rear wheel with help of Epicyclical gear Box to give
number of différent Speed during driving.To reduce torque requirent in the cycle with change in
the pedal mechanism
Integration of Struts & Spring & Hibernate for Enterprise ApplicationsIJMER
This document discusses integrating the Spring, Struts, and Hibernate frameworks to develop enterprise applications. It provides an overview of each framework and their features. The Spring Framework is a lightweight, modular framework that allows for inversion of control and aspect-oriented programming. It can be used to develop any or all tiers of an application. The document proposes an architecture for an e-commerce website that integrates these three frameworks, with Spring handling the business layer, Struts the presentation layer, and Hibernate the data access layer. This modular approach allows for clear separation of concerns and reduces complexity in application development.
Microcontroller Based Automatic Sprinkler Irrigation SystemIJMER
Microcontroller based Automatic Sprinkler System is a new concept of using
intelligence power of embedded technology in the sprinkler irrigation work. Designed system replaces
the conventional manual work involved in sprinkler irrigation to automatic process. Using this system a
farmer is protected against adverse inhuman weather conditions, tedious work of changing over of
sprinkler water pipe lines & risk of accident due to high pressure in the water pipe line. Overall
sprinkler irrigation work is transformed in to a comfortableautomatic work. This system provides
flexibility & accuracy in respect of time set for the operation of a sprinkler water pipe lines. In present
work the author has designed and developed an automatic sprinkler irrigation system which is
controlled and monitored by a microcontroller interfaced with solenoid valves.
On some locally closed sets and spaces in Ideal Topological SpacesIJMER
This document introduces and studies the concept of δˆ s-locally closed sets in ideal topological spaces. Some key points:
- A subset A is δˆ s-locally closed if A can be written as the intersection of a δˆ s-open set and a δˆ s-closed set.
- Various properties of δˆ s-locally closed sets are introduced and characterized, including relationships to other concepts like generalized locally closed sets.
- It is shown that a subset A is δˆ s-locally closed if and only if A can be written as the intersection of a δˆ s-open set and the δˆ s-closure of A.
- Theore
Intrusion Detection and Forensics based on decision tree and Association rule...IJMER
This paper present an approach based on the combination of, two techniques using
decision tree and Association rule mining for Probe attack detection. This approach proves to be
better than the traditional approach of generating rules for fuzzy expert system by clustering methods.
Association rule mining for selecting the best attributes together and decision tree for identifying the
best parameters together to create the rules for fuzzy expert system. After that rules for fuzzy expert
system are generated using association rule mining and decision trees. Decision trees is generated for
dataset and to find the basic parameters for creating the membership functions of fuzzy inference
system. Membership functions are generated for the probe attack. Based on these rules we have
created the fuzzy inference system that is used as an input to neuro-fuzzy system. Fuzzy inference
system is loaded to neuro-fuzzy toolbox as an input and the final ANFIS structure is generated for
outcome of neuro-fuzzy approach. The experiments and evaluations of the proposed method were
done with NSL-KDD intrusion detection dataset. As the experimental results, the proposed approach
based on the combination of, two techniques using decision tree and Association rule mining
efficiently detected probe attacks. Experimental results shows better results for detecting intrusions as
compared to others existing methods
Natural Language Ambiguity and its Effect on Machine LearningIJMER
This document discusses natural language ambiguity and its effect on machine learning. It begins by introducing different types of ambiguity that exist in natural languages, including lexical, syntactic, semantic, discourse, and pragmatic ambiguities. It then examines how these ambiguities present challenges for computational linguistics and machine translation systems. Specifically, it notes that ambiguity is a major problem for computers in processing human language as they lack the world knowledge and context that humans use to resolve ambiguities. The document concludes by outlining the typical process of machine translation and how ambiguities can interfere with tasks like analysis, transfer, and generation of text in the target language.
Today in era of software industry there is no perfect software framework available for
analysis and software development. Currently there are enormous number of software development
process exists which can be implemented to stabilize the process of developing a software system. But no
perfect system is recognized till yet which can help software developers for opting of best software
development process. This paper present the framework of skillful system combined with Likert scale. With
the help of Likert scale we define a rule based model and delegate some mass score to every process and
develop one tool name as MuxSet which will help the software developers to select an appropriate
development process that may enhance the probability of system success.
Material Parameter and Effect of Thermal Load on Functionally Graded CylindersIJMER
The present study investigates the creep in a thick-walled composite cylinders made
up of aluminum/aluminum alloy matrix and reinforced with silicon carbide particles. The distribution
of SiCp is assumed to be either uniform or decreasing linearly from the inner to the outer radius of
the cylinder. The creep behavior of the cylinder has been described by threshold stress based creep
law with a stress exponent of 5. The composite cylinders are subjected to internal pressure which is
applied gradually and steady state condition of stress is assumed. The creep parameters required to
be used in creep law, are extracted by conducting regression analysis on the available experimental
results. The mathematical models have been developed to describe steady state creep in the composite
cylinder by using von-Mises criterion. Regression analysis is used to obtain the creep parameters
required in the study. The basic equilibrium equation of the cylinder and other constitutive equations
have been solved to obtain creep stresses in the cylinder. The effect of varying particle size, particle
content and temperature on the stresses in the composite cylinder has been analyzed. The study
revealed that the stress distributions in the cylinder do not vary significantly for various combinations
of particle size, particle content and operating temperature except for slight variation observed for
varying particle content. Functionally Graded Materials (FGMs) emerged and led to the development
of superior heat resistant materials.
Energy Audit is the systematic process for finding out the energy conservation
opportunities in industrial processes. The project carried out studies on various energy conservation
measures application in areas like lighting, motors, compressors, transformer, ventilation system etc.
In this investigation, studied the technical aspects of the various measures along with its cost benefit
analysis.
Investigation found that major areas of energy conservation are-
1. Energy efficient lighting schemes.
2. Use of electronic ballast instead of copper ballast.
3. Use of wind ventilators for ventilation.
4. Use of VFD for compressor.
5. Transparent roofing sheets to reduce energy consumption.
So Energy Audit is the only perfect & analyzed way of meeting the Industrial Energy Conservation.
An Implementation of I2C Slave Interface using Verilog HDLIJMER
This document describes the implementation of an I2C slave interface using Verilog HDL. It introduces the I2C protocol which uses only two bidirectional lines (SDA and SCL) for communication. The document discusses the I2C protocol specifications including start/stop conditions, addressing, read/write operations, and acknowledgements. It then provides details on designing an I2C slave module in Verilog that responds to commands from an I2C master and allows synchronization through clock stretching. The module is simulated in ModelSim and synthesized in Xilinx. Simulation waveforms demonstrate successful read and write operations to the slave device.
Discrete Model of Two Predators competing for One PreyIJMER
This paper investigates the dynamical behavior of a discrete model of one prey two
predator systems. The equilibrium points and their stability are analyzed. Time series plots are obtained
for different sets of parameter values. Also bifurcation diagrams are plotted to show dynamical behavior
of the system in selected range of growth parameter
Pushing the limits of ePRTC: 100ns holdover for 100 daysAdtran
At WSTS 2024, Alon Stern explored the topic of parametric holdover and explained how recent research findings can be implemented in real-world PNT networks to achieve 100 nanoseconds of accuracy for up to 100 days.
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
AI 101: An Introduction to the Basics and Impact of Artificial IntelligenceIndexBug
Imagine a world where machines not only perform tasks but also learn, adapt, and make decisions. This is the promise of Artificial Intelligence (AI), a technology that's not just enhancing our lives but revolutionizing entire industries.
Unlock the Future of Search with MongoDB Atlas_ Vector Search Unleashed.pdfMalak Abu Hammad
Discover how MongoDB Atlas and vector search technology can revolutionize your application's search capabilities. This comprehensive presentation covers:
* What is Vector Search?
* Importance and benefits of vector search
* Practical use cases across various industries
* Step-by-step implementation guide
* Live demos with code snippets
* Enhancing LLM capabilities with vector search
* Best practices and optimization strategies
Perfect for developers, AI enthusiasts, and tech leaders. Learn how to leverage MongoDB Atlas to deliver highly relevant, context-aware search results, transforming your data retrieval process. Stay ahead in tech innovation and maximize the potential of your applications.
#MongoDB #VectorSearch #AI #SemanticSearch #TechInnovation #DataScience #LLM #MachineLearning #SearchTechnology
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
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.
Building Production Ready Search Pipelines with Spark and MilvusZilliz
Spark is the widely used ETL tool for processing, indexing and ingesting data to serving stack for search. Milvus is the production-ready open-source vector database. In this talk we will show how to use Spark to process unstructured data to extract vector representations, and push the vectors to Milvus vector database for search serving.
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
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Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open Circuit Wind Tunnel Model
1. International
OPEN
Journal
ACCESS
Of Modern Engineering Research (IJMER)
Design, Analytical Analysis, Instrumentation and Flow
Simulation of Sub-Sonic Open Circuit Wind Tunnel Model
Tomar Vishvendra Singh1, Sangwan Vipul2, Singh Shaktiman3,
Singh Raj Kumar4, Agrawal Jubin5
1,2,3,4
Department of Mechanical Engineering, Delhi Technological University, Delhi, 110042, India
5
Department of Mechanical Engineering, ABES-IT, Ghaziabad, 201009, India
ABSTRACT: The Wind Tunnel is well known for its enormous amount of potential in Civil,
Environmental, Automobile and Aeronautical applications. In today’s world, Everyone’s main focus is
to save time, material and money which have compelled us to opt for the experimental testing on scale
models, before the final product is to be shaped. The Wind Tunnel is one such platform, which provides
us the appropriate desired environment conditions around the model scaled to the compatible
dimensions. Therefore, to develop the favorable conditions, the design of the tunnel plays the foremost
role in its proper functioning. In this paper, knowing the intricacy of the tunnel’s requirements, A SubSonic Open Circuit Wind Tunnel (SOWT) Model is developed and simulated, having a Mach Number
(M) of 0.15. The guiding dimensions taken for the Test Chamber are: Length (L T) = 45cm, Height (HT)
= 18cm and Width (WT) = 24cm with maximum operating speed to be 50m/s. Using these, the
secondary design parameters were estimated and the design is finalized. Moreover, the
instrumentation of the Tunnel including Data Acquisition Systems (DAQs) is reviewed.
Keywords: Sub Sonic Open Circuit Wind Tunnel, Mach number, Boundary Layer Modeling
Parameters, Model Testing and Simulation.
I. Introduction
Today, the wind tunnel is an indispensable part of development of modern aircraft, automobile etc as no
one would contemplate committing an advanced design without first measuring its stability, lift and drag
properties. The utility of the wind tunnel is obvious, but it was not the first aerodynamic test device. The quest to
measure drag and various aspects of aviation theory started with the very first advancement in aviation with the
introduction to whirling arm. The whirling arm apparatus (4 feet long) was developed by Benjamin Robins
(1707-1751), a brilliant English mathematician. It spun by a falling weight acting on a pulley and spindle
arrangement having velocities of only a few feet per second at the arm tip (top speeds ranging from 3 to 6 m/s).
The large amount of turbulence posed serious problems in front of experimenters like in determination of the
true relative velocity between the model and air. Also, it was difficult to mount the instruments and measure the
small forces exerted on the model when it was spinning at high speeds. Francis Herbert Wenham (1824–1908), a
council member of the Aeronautical Society of Great Britain, addressed the issue by inventing, designing and
operating the first enclosed wind tunnel in 1871. After some of the experimental studies, it was found that lift-todrag ratios were very high as such wings could support substantial loads, making powered flight which seemed
much more attainable than previously thought possible. Further research work revealed the effect of what is now
known as aspect ratio: long, narrow wings, like those on modern gliders, provided much more lift than stubby
wings with the same areas [1-3].
Wilbur Wright (1867-1912) and Orville Wright (1871-1948) built their first flying machine in August
1899 and then their first unpowered manned glider in 1900. However, the glider was generating far less lift and
more drag than they expected. They developed a simple experiment using natural winds to compare the relative
lifting forces of flat and cambered surfaces. Then they built an aerodynamic balance that showed unambiguously,
which test airfoil (among the two being tested) can develop more lift. Thus for the first time "Wind Tunnel
without Walls" was subjected to test. It confirmed the accepted aerodynamic design tables that they were using,
were seriously in error. This helped them in rectification of the wing area, airfoil curvature. During the
experimental work, they reached at conclusion that without synthesizing a well equipped wind tunnel they could
not continue their work anymore as such they developed the wind tunnel in its true sense and helped themselves
to trigger the flight! [1, 4]
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2. Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open…
Wind tunnels are designed for a specific purpose and speed range. Therefore, there are different types
of wind tunnels and several different ways to classify wind tunnels. On the basis of Speed Regime developed in
the test section relative to the speed of sound (Mach Number „M‟), Wind Tunnels are classified as subsonic (M
< 0.8), transonic (0.8 < M < 1.2), supersonic (1.2 < M < 5.0), hypersonic (M > 5.0). On the basis of Tunnel
Geometry, Wind tunnels are classified as Closed Circuit Wind tunnel (CCWT) and Open Circuit Wind Tunnel
(OCWT) (Fig. 1). A wind tunnel that is closed and re-circulates the air through the test section is called a Closed
Circuit Wind Tunnel. A wind tunnel that is open on both ends and draws air from the atmosphere into the test
section is called an Open Circuit Wind Tunnel [5, 6].
Fig. 1: Classification of Wind Tunnels on the basis of Tunnel Geometry as (a) Closed Circuit Wind Tunnel and
(b) Open Circuit Wind
The OCWTs Models are used to investigate the different automotive designs by testing on scale models
of cars, trucks etc. Airflow over a vehicle determines the drag forces, which in turn affects the vehicle‟s
performance and efficiency. The three basic forces are lift, drag, and side force as measured in an axis system
referenced to the direction of the vehicle. The concept of Lift and Drag can be understood with the help of
airfoil. The airfoil long in the direction perpendicular to the plane of the drawing and the flow can be considered
as two dimensional. The airfoil is tilted with respect to the (undisturbed) flow direction, defined by the angle of
attack (AOA). The force experienced by airfoil is FR. Decomposing the force FR into components FL and FD
{Given by (1) and (2)} perpendicular and parallel to the flow direction. FL is termed as lift force and FD is
termed as drag force, the resistance to be balanced by the propulsion force generated by the engines (Fig. 2). The
expressions for Lift and Drag Forces are as follows:
FL= 0.5 CL ρ A1 u2
….(1)
FD= 0.5 CD ρ A2 u2
….(2)
Fig. 2: Lift and Drag Forces on Airfoil subjected to fluid flow
The designer of an airplane tries to maximize CL and to minimize CD. CL and CD are dependent on the
angle of attack. Usually the CL drops sharply and CD increases strongly at i = 15̊ (approx.) [7].
Wind tunnels have been used widely to simulate airflow about complete aircraft, specific aircraft
components, and to conduct fundamental research concerning flow phenomena related to flight for over a
century. Wind tunnels are made in different shapes and sizes, from just 30 cm long to large enough to contain a
passenger airplane. The various sorts of Wind Tunnels find potential applications in estimation of pollution
dispersion level near the building, investigation of wind-driven rain and building envelop, various aspects of
wind loading on roofs and wind effects on towers and bridges. In Wind Engineering, wind tunnel tests are used
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3. Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open…
to measure the velocity around, and forces or pressures upon structures. Very tall buildings, buildings with
unusual or complicated shapes (such as a tall building with a parabolic or a hyperbolic shape), cable suspension
bridges or cable stayed bridges are analyzed in specialized atmospheric boundary layer wind tunnels. The basic
idea behind all wind tunnels is universal. Depending upon the situations like thermal and hydraulic testing, it
generates uniform air flows with low turbulence intensity. The aerodynamic principles of the wind tunnel work
equally on watercraft, except the water is more viscous and so sets greater forces on the object being tested.
External flow tunnels are used to study the external flow through the chassis climatic tunnels and used to
evaluate the performance of door systems, braking systems etc. under various climatic conditions. Aero-acoustic
tunnels are used in the studies of noise generated by flow and its suppression. Wind tunnel tests are also
performed to measuring the air movement of the fans, Turbine Blades, Propellers etc at a specific pressure
exactly [3, 8-12].
A lot of research work have been accomplished to optimize the Wind Tunnel Design and still to make it
better at various levels depending upon the situations research work is still in progress. Peter et al. in their work,
focused on the wind tunnel test section flow quality and its application to a numerical CCWT by studying the
effects of various variables for its evaluation [8]. Diana et al. evaluated the design criteria that supported the
choice of the original solution for potential application of a new large wind tunnel in Civil, Environmental and
Aeronautical aspects and discussed the feasibility of a plant on the basis of experimental analysis on a 1:9 scale
model [13]. Lohan [14] focused on the design and application of LSWTs having well-defined, controllable,
uniform flow of air for experimental and design validation purposes. Senol and Cinar with the help of Flow
Simulation Fluent 6.0 program corrected the earlier developed design of a suction-type SOWT by simulating it
in computer environment [15]. Eckert et al. discussed some Aerodynamic design guidelines and computer
program for estimation of SSWT performance [16]. The enormous amount of research work and experiments
undertaken in wind tunnels and their importance for human life motivated the high demands that are posed on
optimum design level for Wind Tunnels against the minimum cost with optimum output. This paper deals with
the Sub-Sonic Open Circuit Wind Tunnel (SOWT) with negligible effect of compressibility. Following the
research works and significant guidelines related to design consideration, the design for SOWT Model is
developed. The Mach Number of 0.15 allows it to use for aerodynamics tests and performance of some scale
models having speeds around 150 km/hr.
II. Design of Sub Sonic Open Circuit Wind Tunnel Model
The Wind tunnels cannot be perfect simulations of environmental conditions, but up to some extent
they can be treated as ideal to surrounding conditions. The degree to which they are flawed is measured with the
help of Reynolds Number. The SSWTs are designed to provide a well-defined, controllable, uniform flow of air
for experimental and design validation purposes. These tunnels when applied as open circuit cannot be used
where a very high accuracy level and precise results are required due to their inability to control air flow up to a
large extent. However, with proper designs and controlled instrumentation, these tunnels can be made to produce
accurate results within close limit to practical value. The major advantage associated with this tunnel is its SetUp and Maintenance Cost, which is very small as compared to CCWT. The leading manufacturer of automobiles
use the OCWTs for the Drag and performance estimation of the vehicles as with current technology & designs,
these tunnels are giving results quite close to practical values under proper calibrations.
The OCWT (Fig. 3) consists of five basic parts, which are (From front to back) the Settling Chamber,
the Contraction Cone, the Test Section, the Diffuser and the Drive Section. The Settling Chamber is at the very
front of the wind tunnel and is made up of screens and honeycomb-shaped mesh, which straighten out the air and
reduce turbulence. The Contraction Cone forces a large volume of air through a small opening in order to
increase the wind velocity in the tunnel, as there is gradual decrease in area. The Test Section is the place where
a model is mounted on sensors. The Diffuser is at the end of the Test Section and keeps the air running smoothly
as it goes toward the back. It also increases in volume in order to slow the air down as it exits the tunnel. The
Drive Section is at the very back of the wind tunnel, and it is where the fan is housed and draws air into the wind
tunnel by blowing air out of it and hence reduces turbulence along with greater control of the airflow through the
tunnel. The decisive characteristic of wind tunnels lies in the flow quality inside the test chamber and the overall
performances.
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4. Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open…
Fig. 3: Isometric View of Sub-Sonic Open Circuit Wind Tunnel Model developed Solid-Works
Three main criteria that are commonly used to define them are: maximum achievable speed, flow
uniformity and turbulence level. Hence in general, the design aim of a wind tunnel is to get a controlled flow in
the test chamber, achieving the necessary flow performance and quality parameters. The main specifications for
a wind tunnel are the dimensions of the test section and the desired maximum operating speed. Also, it is crucial
to avoid flow separation close to the walls of the contraction zone. In the subsequent sections, the design of each
of the component of the Wind Tunnel is developed one by one, from the design of the Test Chamber to the
Diffuser.
2.1 Test Chamber Design
The test chamber (Fig. 4) is the most delicate part of the tunnel and is also called as “The Heart of the
Wind Tunnel” as it is the region for experimental study, carrying the scale model, sensors etc along with the
controlled flow. Its size must be defined according to the wind tunnel main specifications, which also include the
operating speed and desired flow quality. Its size and operating speed determine the maximum size of the models
and the maximum achievable Reynolds number. In most of the cases, its cross-section is square in shape and its
area should be decided according to the scale model which is going to be tested. The equivalent frontal area of
the model should not be higher than 10% of the test chamber cross-sectional area. The width to height ratio
adopted for 3-D Tests is 4:3. The Test Section Assembly is composed of the Test Section (Plexiglas) to avoid
pressure loss and the Test Section Base (wooden stand and sensor mounts) [14-19].
Fig. 4: Dimetric View of The Test Chamber developed using Solid-Works.
2.2 Contraction Cone Design
The Contraction Cone is the most important part in the design of a Wind Tunnel as it has the highest
impact on the Test Chamber flow quality. It accelerates the flow from the Settling Chamber to the Test Chamber
as such also known as „Nozzle‟. It also helps in reduction of flow turbulence and non-uniformities in the test
chamber. The flow acceleration and non-uniformity attenuations mainly depend on the ratio of cross-section area
of inlet to that of exit, termed as contraction ratio (N). Theoretically, the value of N should be as large as
possible but it has an upper limit as it strongly influences the overall wind tunnel dimensions and hence its cost.
For the Wind Tunnels used in civil or industrial applications, a contractions ratio between 4.0 and 6.0 may be
sufficient reducing the flow turbulence and non-uniformities levels to the order of 2.0%, which is acceptable for
many applications. Further with just one screen placed in the settling chamber it reduces to 0.5%. Even this is a
very reasonable value for some aeronautical purposes.
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5. Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open…
….(3)
The second characteristic of the contraction Cone is its shape, taking into account that the contraction is
rather smooth. For this 1-D (One-Dimensional) approach to the flow analysis is applied to determine the
pressure gradient along it. The important point of consideration is the pressure distribution on the contraction
walls, as if it has some regions with adverse pressure gradient, it may produce local boundary layer separation
which can increase the turbulence level considerably, resulting in poor flow quality in the test chamber. The
solution to this is to make the ratio of the radius of curvature to the flow width about the same at each end. But at
the upstream end the radius of curvature cannot be too large as it leads to slow acceleration and therefore
increased rate of growth of boundary-layer thickness which causes centrifugal instability in the tunnels having
laminar flow. The contraction semi-angles: α/2 and β/2 are taken to be in the order of 12º, this causes the
contraction cone to possess a reasonable length and a good fluid dynamic behavior. Bradshaw et al.
recommended two segments of third degree polynomial curves for deciding the exact curve (Fig. 5) for the
Contraction Cone [14-20]. The polynomials are:
y = aW + bWx + cWx2 + dWx3
….(4)
y = aN + bNx + cNx2 + dNx3
….(5)
Fig. 5: Fitting Polynomial for the Contraction Cone Curve developed using Solid-Works
Fig. 6: Isometric View of The Contraction Cone developed using Solid-Works
The Contraction Cone developed using the above curve (Fig. 6) doesn‟t allow boundary layer to
separate and keep boundary layer thickness within certain limit. It provides the favorable flow to the Test
Chamber.
2.3 Settling Chamber Design
The Settling Chamber (Fig. 7) is the very first region designed to provide controlled high quality flow
to the Contraction Cone by attenuating the various flow components responsible for turbulence. To develop high
quality flow some devices like screens and honeycombs etc are installed to increase the flow uniformity and to
reduce the turbulence level at the entrance of the contraction cone. They produce a relatively high total pressure
loss. Honeycomb is very efficient at reducing the lateral turbulence, as the flow pass through long and narrow
pipes. But the problem with Honeycombs is, it introduces axial turbulence of the size equal to its diameter which
restrains the thickness of the honeycomb. To tackle this problem, Screens are introduced as they reduce
longitudinal turbulence very efficiently. In this case, the problem is that in the Contraction Cone the lateral
turbulence is less attenuated than the longitudinal one. Hence, to obtain better flow characteristics, a
combination of Honeycombs and Screens is used. This configuration requires the honeycomb to be located
upstream of 1 or 2 screens [14-21].
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6. Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open…
Fig. 7: Isometric View of The Settling Chamber developed using Solid-Works
2.4 Diffuser Design
The Diffuser (Fig. 8) plays an important role in controlling the flow quality inside the Test Chamber by
avoiding the flow detachment as in case of flow detachment; the pressure pulsation is transmitted upstream into
the test chamber, resulting in pressure and velocity non-uniformities. To avoid flow detachment, the maximum
semi-opening angle in the diffuser has to be smaller than 3.5° [14-21].
Fig. 8. Dimetric View of The Diffuser developed using Solid-Works.
III. Analysis of Sub Sonic Open Circuit Wind Tunnel Model
The Primary Design Parameters for the overall design of the Wind Tunnel include Test chamber
dimensions i.e. Width (WT), Height (HT) and length (LT). With the help of these parameters cross-sectional area
of the Test Chamber can be calculated as AT = WT.HT. The hydraulic diameter is given by the relation [14-21]:
….(6)
The Contraction ratio (N) is taken 5 for the Wind Tunnel with Mach number (M=0.15), having
Maximum operating speed (VT) to be 50 m/s. These Design variables can be summarized in the Table. 1. The
dimensions for the Test Section are WT = 24cm, HT = 18cm, LT = 45cm and the VT is taken to be 50m/s which
gives us the Mach Number (M) to be 0.15. So, The Designing of all other parts is done based on these
dimensions with N = 5. The semi angle in the Contraction Cone (α/2) is taken as 12̊ and the semi angle in the
Diffuser (θ/2) is taken as 3.5̊ . The non dimensional lengths for the Settling Chamber (lS) and Diffuser (lD), for
Sub-Sonic Open Circuit Flow, are taken as 0.5 and 3.2 respectively. The calculated parameters are displayed in
Table. 2. And the final design for this analytical analysis is represented by (Fig. 9). The total length of the
SOWT is:
LWT = LS + LC + LT + LD
….(7)
LWT = 26.83 +45 + 69.78 +76.80 = 218cm
Hence, LWT is equal to 218cm.
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7. Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open…
Table. 1: The primary and secondary design parameters required for designing of SOWT Model
PRIMARY DESIGN PARAMETERS
SECONDARY DESIGN PARAMETERS
TEST CHAMBER WIDTH (WT)
SEMI ANGLE IN CONTRACTION CONE (Α/2)
TEST CHAMBER HEIGHT (HT)
SEMI ANGLE IN DIFFUSER (Θ/2)
TEST CHAMBER LENGTH (HT)
SETTLING CHAMBER NON DIMENSIONAL LENGTH (LS)
CONTRACTION RATIO (N)
DIFFUSER NON DIMENSIONAL LENGTH (LD)
MAXIMUM OPERATING SPEED (VT)
SETTLING CHAMBER LENGTH (LS)
MACH NUMBER (M)
CONTRACTION CONE LENGTH (LC)
DIFFUSER LENGTH (LD)
Table. 2: Secondary design Parameters of SOWT Model
Fig. 9: Isometric View of the complete model of SOWT developed using Solid-Works
IV. Instrumentation of Sub Sonic Open Circuit Wind Tunnel Model
The instrumentation of wind tunnel emphasizes on the various instruments and Data Acquisition
Systems (DAQs) required by a tunnel for its proper functioning, Pressure and Flow measuring ability, Flow
Visualization and Image Acquisition. In the instrumentation of the tunnel, Standard data acquisition (DAQ),
Motion Control, and Image Capture hardware play a very crucial role. Data acquisition is the process of
sampling signals that measure real world physical conditions and converting the resulting samples into digital
numeric values that can be manipulated by a computer. Data acquisition systems convert analog waveforms into
digital values for processing. The various components of data acquisition systems are Sensors (convert physical
parameters to electrical signals), Signal conditioning circuitry (convert sensor signals into a form that can be
converted to digital values) and Analog-to-Digital converters (convert conditioned sensor signals to digital
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8. Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open…
values). Further, various operations can be integrated to the system including Flow Visualization with Image
Acquisition, Multipoint differential pressure scanning, Hot Wire Anemometry, Force and Moment measurement
using internal balances, Roll, Pitch and Yaw angle measurements, and Noise and Temperature measurements.
For Pressure and Flow Measurements, measuring devices coupled with DAQs like LabVIEW and
pressure scanners etc. can be used. Similarly for Force and Moment Measurements, Six-component Strain Gauge
Balances can be applied. And for Flow Visualization and Image Acquisition, light sheets using Argon-ion lasers
with CCD cameras and recording system can be used to capture and analyze the exact trajectory of flow
particles, even sometimes incorporating IMAQ hardware and software (IMAQ vision). With such a proper
design and proper instrumentation, a wind tunnel can be used for Full-model tests with sting support mechanism,
Half-model testing with external balance, Two-dimensional model testing, Ground effect simulation with moving
belt, Gust and cross wind simulation, Aero-acoustic testing etc. For a Wind Tunnel with M < 0.3, the
instrumentation required is not so much complex but still it requires attention for getting accurate and precise
results [22-26].
V. Simulation of Sub Sonic Open Circuit Wind Tunnel Model
Solid-Works Flow-Express is a first pass qualitative flow analysis tool which gives insight into water or
air flow inside the Solid-Works model. Using this, the simulation is carried out. The constants and assumptions
used in the simulation study are tabulated as (Table. 3):
Table. 3: The constants and various parameters determining the environment conditions for the simulation of
SOWT Model.
CONSTANTS AND VARIOUS PARAMETERS VALUES
Inlet Pressure
Outlet Pressure
External Ambient Temperature
Gas Constant
Kinematic Viscosity
Acceleration due to gravity
Air Density
Entrance Speed
100890 Pa
100000 Pa
293.20 ̊ K
287 J/kg-̊ K
1.714 x 10-5 Kg/m-s
9.81 m/s-2
1.2251 kg/m3
11.335 m/s
The flow velocity simulation of the designed Wind Tunnel have been performed (using particle flow
visualization) under the above mentioned environment conditions (Fig. 10). Also, the variation of flow velocity
against the length of the tunnel is obtained. Fig. 11 shows the flow speed changes within the wind tunnel. The
lowest flow speed is occurred at the surfaces of the entrance section, at the corners joining the settling chamber
and the contraction cone, and the diffuser exit. Flow speed accelerates while passing through the contraction and
it reaches the highest required value (49.118 m/s ⸗ 50 m/s) in the test chamber. Also the flow rate increases
throughout the contraction and remains constant throughout the test chamber. Flow rate gradually decreases as
air exits from the test chamber and enters into the diffuser. Further, at the diffuser exit, it reaches the same value
with the wind tunnel entrance.
Fig. 10: Particle Flow Visualization of Air as fluid inside the SOWT, illustrating Velocity variation along the
length of the Tunnel
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Fig. 11: Flow Velocity Variation of Air as fluid inside the SOWT along the length of the Tunnel
The graphic of static pressure distribution and velocity changes throughout the wind tunnel is shown in
Fig. 12. The static pressure on the edges of the entrance section is the maximum value (100890 Pa.). It can be
said that a major turbulence and counter pressure zone are created at these points. Static pressure values are
closed to the each others at the settling chamber (x=2.5 ft.) and the diffuser exit (x=7 ft.). A bit of static pressure
drop is occurred in the middle zone of the contraction cone. The pressure is reached to the lowest value at the
test chamber exit. Since the static pressure changes are very small throughout the test chamber, it can be said that
there is not any boundary layer thickening along the test chamber walls and the air flow quality is good.
Fig. 12: Flow Velocity Variation (Quantitatively) and Pressure Distribution (Quantitatively) of Air as fluid inside
the SOWT along the length of the Tunnel
VI. Conclusion
The design of Low Cost SOWT model has been generated. The main considerations like Boundary
Layer Separation, Controlled Air Flow Quality, Turbulence Intensity, Stream Line Flow, Cost-Effectiveness,
Design Ease and Mach Number (M = 0.15) etc were taken into the account and accordingly the model is
designed. The primary design parameters of the Test Chamber were taken as the baseline and following the
design guidelines, the secondary design parameters for approximately 220 cm tunnel were calculated. The
Contraction Cone and the Test Chamber section were given special attention as they have direct influence on the
scale model testing and the data generated. A brief insight is given to the instrumentation segment of the tunnel,
especially to the various measurements and DAQs that are still playing their part in research and development
concerning the various wind tunnel applications. The Velocity Variations and Static Pressure changes throughout
this model were simulated. Moreover, the quantitative variation of Velocity and Pressure is plotted against the
tunnel‟s length. With the final design, the maximum operating speed obtained at the test chamber is 49.12 m/s,
quite close to desired value 50 m/s. The air flow obtained is of smooth quality with no boundary layer thickening
process at the Test Chamber. Thus, the final SOWT Model design obtained can be used wherever the maximum
operating velocity required is 50 m/s or 180 km/h, which generally is the case with the automobiles at high
speeds.
| IJMER | ISSN: 2249–6645 |
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| Vol. 4 | Iss. 1 | Jan. 2014 |51|
10. Design, Analytical Analysis, Instrumentation and Flow Simulation of Sub-Sonic Open…
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| IJMER | ISSN: 2249–6645 |
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| Vol. 4 | Iss. 1 | Jan. 2014 |52|