Wind tunnel
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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.
Wind tunnel
- 1. Gayon, Jio RossGayon, Jio Ross Godfrey S.Godfrey S. Oarde, Kevin Victor L.Oarde, Kevin Victor L. Zaide, John Chester A.Zaide, John Chester A. Wind TunnelWind Tunnel
- 2. 2/26 Frank WenhamFrank Wenham Benjamin RobinsBenjamin Robins George CayleyGeorge Cayley Osborne ReynoldsOsborne Reynolds Hiram MaximHiram Maxim Wright BrothersWright Brothers
- 3. 3/26 IntroductionIntroduction What is a Wind Tunnel? AE 412 Introduction Classifications Elements Types Shapes Flow Visualization a facility that provides a controllable flow field for investigating various flow phenomena and testing aerodynamic models a tool used in aerodynamic research to study the effects of air moving past solid objects *** Advantage: experiments can be performed under well-controlled flow circumstances compared to open environment experiments
- 4. 4/26 National Full-Scale Aerodynamics Complex , NASA Ames Research Center, United States
- 5. 5/26 Aeronautical Wind Tunnels Automobile Tunnels Aeroacoustic Tunnels Classifications of Wind TunnelClassifications of Wind Tunnel Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 6. 6/26 Aeronautical Wind TunnelsAeronautical Wind Tunnels High Reynold’s Number Tunnels Pressurized Tunnels Heavy Gas Tunnels Cryogenic Tunnels High-altitude Tunnels V/STOL Tunnels Spin Tunnels Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 7. 7/26 Tunnels are also classified by flow speed: Subsonic (M<.8), Transonic (.8<M<1.2), Supersonic (1.2<M<5.0), or Hypersonic (M>5.0) Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 8. 8/26 Wind tunnels may also be classified according to their air pressure: atmospheric variable- density or their size: ordinary full-scale Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 9. 9/26 Elements of aElements of a Wind TunnelWind Tunnel Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 10. 10/26 straightens the airflow *** The less turbulence there is, the better the wind tunnel will simulate actual flying conditions usually includes a honeycomb flow straightener and wire mesh smoothing screens that produce a smooth airflow; effective at reducing swirling currents in the tunnel airflow Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 11. 11/26 *** purpose: take a large volume of low-velocity air and reduce it to a small volume of high- velocity air Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 12. 12/26 models of wings or planes are placed here *** As airflow is brought to the desired velocity, sensors measure forces, such as lift and drag, on the test article. Lift is the force on the wing opposite the force of gravity. Lift holds a plane in the air. Drag is the force on the wing in the direction of the airflow. An engine must overcome this force to move a plane through the air. Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 13. 13/26 Shapes of Test SectionShapes of Test Section Rectangular (General Purpose) Circular (Axisymmetric Model) Elliptical (Aircraft Model) AE 412 Introduction Classifications Elements Types Shapes Flow Visualization
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- 15. 15/26 where the air coming out of the test section slows down prior to exhausting or recirculating a device to lower the air flow speed, consequently reduce the pressure loss due to friction Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 16. 16/26 provides the force that causes air to move through the tunnel *** Fan drive: provide a pressure increase of flow, to overcome the pressure loss in the tunnel circuit. Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 17. 17/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 18. 18/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 19. 19/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 20. 20/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 21. 21/26 Types of Wind TunnelTypes of Wind Tunnel Closed-type Open-type Introduction Classifications Elements Types Shapes Flow Visualization AE 412 Blowdown Shock Tube
- 22. 22/26 Open-type Wind TunnelOpen-type Wind Tunnel also called an Eiffel tunnel open on both ends and draws air from the room into the test section Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 23. 23/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 24. 24/26 AdvantagesAdvantages Low construction cost. Superior design for propulsion and smoke visualization. There is no accumulation of exhaust products in an open tunnel DisadvantagesDisadvantages Poor flow quality possible in the test section High operating costs Noisy operation Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 25. 25/26 Closed-type Wind TunnelClosed-type Wind Tunnel also called an Prandtl tunnel or Gottingen tunnel *** Air is conducted from the exit of the test section back to the fan by series of turning vanes; air is returned to the contraction section and back to the test section; air is continuously circulated Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 26. 26/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 27. 27/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 28. 28/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 29. 29/26 AdvantagesAdvantages Superior flow quality in the test section Low operating costs Quiet operation DisadvantagesDisadvantages Higher construction cost Inferior design for propulsion and smoke visualization Hotter running conditions than an open return tunnel Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 30. 30/26 has a high pressure vessel upstream of the test section and a low pressure reservoir downstream of the test section used for supersonic testing. Blowdown Wind TunnelBlowdown Wind Tunnel used for hypersonic testing Shock TubeShock Tube Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 31. 31/26 Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 32. 32/26 AdvantagesAdvantages High Mach capability Lower construction and operating costs. Superior design for propulsion and smoke visualization Smaller loads on model during startup because of faster starts DisadvantagesDisadvantages Shorter test times require faster (often more expensive) instrumentation. Need for pressure regulator valves. Noisy operation. Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 33. 33/26 used to study aerodynamic flow under a wide range of temperatures and pressures that are difficult to obtain in other types of testing facilities; are also used to investigate compressible flow phenomena and gas phase combustion reactions Shock TubeShock Tube Introduction Classifications Elements Types Shapes Flow Visualization AE 412
- 34. 34/26 Flow VisualizationFlow Visualization aids the people to see the movement of air while inside the wind tunnel used to make the flow patterns visible
- 35. 35/26 Qualitative Smoke Tufts Evaporating Suspensions Oil Fog Sublimation Quantitative Particle Tracking Velocimetry Particle Image Velocimetry Laser Speckle Velocimetry Optical Shadowgraph Schlieren Photography Interferometry
- 37. 37/26 Smoke- Tufts- Oil- Qualitative MethodsQualitative Methods Evaporating Suspensions Fog-
- 38. 38/26 Quantitative MethodsQuantitative Methods Particle Tracking Velocimetry Particle Image Velocimetry Laser Speckle Velocimetry