Wind Tunnel Testing - 123seminarsonly
Sherwood Heights School2006 Science ProjectWind Tunnel TestingResearch PaperAndrej KraljFebruary 14, 2006
IntroductionWind tunnel testing is used to support many major development processes involvingaerodynamics. It is used for aircraft, helicopters, cars, trains, and laboratory research.A wind tunnel is a research tool developed to assist with studying the effects of air moving overor around solid objects. The wind tunnel provides the engineers with valuable data on scalemodels. The wind tunnel is important contribution of the Wright brothers to the science ofaerodynamics.Wind Tunnel StructureMain components of a wind tunnel are: Drive Section, Settling Chamber, Contraction Cone, TestSection and Diffuser. Flow straighteners, honeycomb layers for reduced turbulence, airexchangers and diffusers are other common features. Measurement equipment and testingprocedures include instruments for the measurement of pressure, temperature, forces, moments,turbulence intensity, etc.The ViGYAN Low Speed Wind TunnelWind Tunnel Testing - Research Paper.docPage 2 of 5
Drive Section is the section of a wind tunnel that provides the force that causes the air to movethrough the tunnel. Settling Chamber is the section of a wind tunnel where the airflow isstraightened and turbulence is reduced, normally prior to entering the contraction cone.Contraction Cone is the section of a wind tunnel where reducing the cross-sectional area of thetunnel reduces a large volume of low-velocity air to a small volume of high-velocity air. TestSection is the section of a wind tunnel where the model and sensors are placed. Diffuser is thesection of a wind tunnel where the velocity of the airflow is reduced by flowing it into a part ofthe tunnel with increasing cross-sectional area.Wind Tunnel ClassificationWind tunnels may be classified according to their basic architecture (open-circuit, closedcircuit), according to their speed (subsonic, transonic, supersonic, hypersonic), according to theair pressure (atmospheric, variable- density), or their size (ordinary ones or full-scale). In anopen-loop tunnel, the air flows in one end of the tunnel and out the other. In a closed-looptunnel, the air is recirculated.There are a number of special wind tunnels (metereologic tunnel, shock tunnel, plasma-jettunnel, hot-shot tunnel).Wind Tunnel Testing - Research Paper.docPage 3 of 5
Wind Tunnel CorrectionsThe test conditions are never the same as the operational conditions. Among the most wellknown effects there are the scale effects, the flow blockage, due to the presence of the model inthe test section and wall boundary layers.Other effects are dependent on the type of experiments performed, for example angle of attackcorrections for a wing. Wind tunnel correction requires special analysis and processingtechniques.Wind Tunnel HistoryThe Wright brothers, working with Octave Chanute invented and built a simple wind tunnel in1901 to study the effects of airflow over various shapes while developing their revolutionaryWright Flyer. Before building their own wind tunnel, the Wright brothers employed anunconventional testing machine: a bicycle with a third wheel mounted horizontally on the frontof the frame. Two test shapes were mounted on the wheel, and the bicycle was pedaled rapidlyup and down the streets of Dayton, Ohio. It is estimated that it took the Wright Brothers less than20 hours of wind tunnel testing to produce their successful Flyer.Wind Tunnel Testing - Research Paper.docPage 4 of 5
The Douglas DC-3, one of the most successful commercial aircraft ever built, required about 100hours of wind tunnel testing. Wind tunnel time has been steadily increasing since: the Boeing747 required over 1000 tunnel hours; the NASA Space Shuttle testing required nearly 10 years oftime.Use of Wind TunnelsSome tests performed in the wind tunnel include:Drag/Lift measurements on aircraft, helicopters, missiles, racing cars.Drag/Lift/Moment characteristics of airfoils and wings.Static stability of aircraft and missilesDynamic stability of aircraft.Surface pressure distributions.Flow visualizations (with smoke, oil, talcum).Propeller performances (torque, thrust, power, efficiency, etc.).Performances of turbofan engines.Wind effects on buildings, towers, bridges, and cars.The Advantages Of Wind TunnelsAdvantages of wind tunnels include reliable and consistent airflow, low turbulence, ability tomake precise measurements, and reproducible conditions and results. Many things can benefitfrom wind tunnel testing. For example, reduced aerodynamic drag reduces fuel costs for longdistance truckers and increases top speeds of racecars. Buildings can be tested in wind tunnels tohelp determine stresses from high winds.References1. Wikipedia – Wind Tunnel2. Advanced Topics in Aerodynamics – Wind Tunnel and Experimental AerodynamicsNoteFront Page Photo: NASA wind tunnel with the model of a planeWind Tunnel Testing - Research Paper.docPage 5 of 5
Wind Tunnel Testing - Research Paper.doc Page 5 of 5 The Douglas DC-3, one of the most successful commercial aircraft ever built, required about 100 hours of wind tunnel testing. Wind tunnel time has been steadily increasing since: the Boeing 747 required over 1000 tunnel hours; the NASA Space Shuttle
Wind Tunnel Testing For Teachers: Teacher Resource Lesson Goal The Wind Tunnel Testing lesson focuses on wind tunnel tests that engineers in many industries use to when developing products such as airplanes, cars, and buildings. Teams of students build their own mode
Tunable compression of wind tunnel data 507 2. Wind-tunnel testing Fig. 1 shows a typical wind tunnel model instrumented with pressure taps. For each wind direction (or, equivalently, the model being placed on a rotating table, for each orientation of the model with respect to the mean flow
Wind tunnel testing is not cheap, however. In addition to the cost of the wind tunnel itself, there is the requirement for the infrastructure to house the wind tunnel and the cost of electricity to run the tests. While a crude wind tunnel c
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WIND TUNNEL TESTING: - 2 - Alan G. Davenport Wind Engineering Group A GENERAL OUTLINE 2 THE MODELLING OF THE SITE AND THE WIND 2.1 General The basic tool used is the Laboratory's Boundary Layer Wind Tunnel. This wind tunnel is designed with a very long test section, which allows exten
covers wind tunnel testing, rather than the wind tunnel procedure, of which wind tunnel testing is only a part. Improvements in the methods for determining wind loads on buildings and other struc-tures can eliminate the underestimation of wind effects on some types of buildings or re-duce unnecessary cos
simulation (LES) and validation with wind tunnel data obtained from RWDI USA LLC, Miramar FL (Dagnew et al. 2009). 2 GENERAL OUTLINE OF WIND TUNNEL TESTING . The wind tunnel testing facility has a testing section of 8.5ft wide by 7ft tall. The floor has me-chanical systems which monitor the d
found in API RP 500, API RP 505 and NFPA 497 are examples of the direct example approach method. This approach utilizes engineering judgment to determine the extent of the hazardous area classification. The diagrams and the boundary distances utilized are selected based on the type of installation, volume and properties of the hazardous gases/vapors. The second ANSI method, less commonly used .
