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Wind tunnel testing aerospace

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Wind tunnel testing aerospace

  2. 2. Wind TunnelsObjective• Accurately simulate the fluid flow aboutatmospheric vehicles• Measure -Forces, moments, pressure, shearstress, heat transfer, flow field2
  3. 3. Working of wind tunnel3
  4. 4. WIND TUNNEL LAYOUTS Closed Return Open Return Double Return Annular Return4
  5. 5. 5Closed Return(OpenTest Section)
  6. 6. 615 Hp. DualCentrifugal BlowerExhaustExhaustLouversfor SpeedAdjustmentTest Section18 inch Diameter25 to 1 ContractionScreens High Contraction Wind TunnelTop ViewDiffuserOpen Return(Closed Section)
  7. 7. 7Double Return
  8. 8. 8Annular WindTunnel
  9. 9. TYPES OF WIND TUNNELS Subsonic Transonic Supersonic Hypersonic Specialty (Automobiles)9
  10. 10. SUBSONIC TUNNELS Low speed wind tunnels are used foroperations at very low machnumber(M<0.5), with speeds in the testsection up to 480 km/hThey may be ofopen-return type with air moved by apropulsion system.10
  11. 11. 1180X120NASA AMES
  12. 12. 1280x120 WindTunnelNASA Ames
  13. 13. 1312 Foot PressureTunnel
  14. 14. TRANSONIC WIND TUNNELS High subsonic wind tunnels (0.4 < M < 0.75)or transonic wind tunnels (0.75 < M < 1.2)are designed on the same principles as thesubsonic wind tunnels.14
  15. 15. TRANSONIC WIND TUNNEL Testing at transonic speeds presentsadditional problems, mainly due to thereflection of the shock waves from the wallsof the test section15
  16. 16. 168x6 Functions & CapabilitiesThe 8x6 Foot Supersonic WindTunnel providescustomers with a Facility capable of testing largescale aero propulsion hardwareRelative altitude 1000 - 35000 ftDynamic Pressure 3.6 - 4.8 x 106/fTemperature 60 - 250oF
  17. 17. 178X6AT NASA LEWIS
  18. 18. SUPERSONIC WIND TUNNELS A supersonic wind tunnel is a wind tunnelthat produces supersonic speeds (1.2<M<5)The Mach number and flow are determinedby the nozzle geometry.18
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  22. 22. HYPERSONIC WIND TUNNELS A hypersonic wind tunnel is designed togenerate a hypersonic flow field in theworking section. The speed of these tunnels vary from Mach5 to 15.22
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  25. 25. AUTOMOBILE WIND TUNNELSExternal flow tunnels - Used to study theexternal flow through the chassis Climatic tunnels - Used to evaluate theperformance of door systems, brakingsystems etc. under various climaticconditions.25
  26. 26. 26
  27. 27. TYPES OF WIND TUNNELTESTING ForceTest Force measurement requires a force to beexerted (lift & drag forces so termed forcetest) The balance can measure only two forces:lift & drag27
  28. 28. 28
  29. 29. TYPES OF WIND TUNNELTESTING PressureTests Insert tiny tubes into the model surface orairstream and connect them to a pressuremeasuring device29
  30. 30.  PressureTest: Lowered pressure over the wing surfacereduced the pressure in the manometertubes and draws the water level up to a highlevel The lower the pressure, the higher the waterlevel goes30
  31. 31. TYPES OF WIND TUNNELTESTING Flow Patterns Allow the streamlines of air flow to look atthe body’s aerodynamic properties Tufting allows for the flow patternvisualization31
  32. 32. 32Flow Patterns
  33. 33. INSTRUMENTS USED INWIND TUNNELS 1.Force Balance 2.Static Pressure Measurement 3.Strain gauge 4.Spring Gauge 5.Laser DopplerVelocimetry 6.Laser Sheet33
  34. 34. FORCE BALANCE34
  36. 36. STRAIN GAUGE36
  37. 37. SPRING GAUGE37
  39. 39. LASER SHEET39
  40. 40. HOW ARE CARS TESTED INWIND TUNNELS?? It is used to quantify and validate what is goingon aerodynamically to the vehicle bymeasuring forces exerted on the body througha 6 component balance.40
  41. 41. HOW ARE CARS TESTED INWIND TUNNELS?? Adding a rear wing to your car might gain youdown force, but a wind tunnel will tell you infact if it is, how much, and how it affected theoverall front to rear balance of your car.41
  42. 42. HOW ARE CARS TESTED INWIND TUNNELS?? Each test will output the drag, down force(front & rear), and side force (front &rear), yaw/pitch/roll moments, in order to seethe big picture of what is really happening forany given configuration.42
  43. 43. 43FewExamples
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  45. 45. COST OF A WIND TUNNEL A high quality portable vertical wind tunnelwill cost you anywhere from 1.6crores to4.1crores.This type of tunnel canaccommodate skydivers as well as tourists.45
  46. 46. WIND TUNNELS IN THEWORLD1.Altitude IcingWindTunnel(Ontario Canada)2.Wright BrothersWindTunnel(MITMassachusetts USA)46
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  48. 48. WIND TUNNELS IN THEWORLD 3.WindTunnel at NASA Ames (World’sLargest USA) 4.Langley Low PressureTurbulenceWindTunnel(NASAVirginia USA)48
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  50. 50. REFERENCES www.wikipedia.com www.nasa.org50
  51. 51. THANK YOU51