Wind Tunnel Testing

Module 5

5.1 Wind Tunnel Types
5.2 Wind Tunnel Techniques
5.3 Wind Tunnel Measurements
5.4 Numerical Problems
5.1 Wind Tunnel Types
Wind Tunnel
Wind Tunnel
A wind tunnel is a powerful, enclosed tube that moves air (or another fluid) over a stationary object (like a car, plane model, or building) to simulate flight or wind conditions, allowing engineers to study aerodynamic forces, drag, lift, and flow patterns in a controlled environment to improve designs for efficiency and safety. allowing engineers to study aerodynamic forces, drag, lift, and flow patterns in a controlled environment to improve designs for efficiency and safety.
Wind Tunnel parts
A wind tunnel's core parts include the Fan Assembly (motor/blades), Settling Chamber (with screens/honeycomb for smooth flow), Contraction Cone (accelerates air), Test Section (where models are placed), Diffuser (slows air), and often Turning Vanes & Heaters as shown in simulation.
Function of settling Chamber
Settling Chamber or inlet is a large area where air calms down before the test section. Honeycomb: A cellular structure that straightens swirling air (reduces swirl). Screens: Fine mesh screens that further smooth the flow and reduce turbulence.
Wind Tunnel types
Wind tunnels are commonly classified based on flow speed, circuit type, purpose, and special operating conditions.
Compact Wind Tunnel Simulator

Diameter Controls

100 units
50 units
80 units

Length Controls

100 units
180 units
100 units

Design Constraints:

  • Inlet diameter = Screen exit = Contraction inlet
  • Contraction inlet > Contraction outlet
  • Contraction outlet = Test section inlet/outlet
  • Test section outlet < Diffuser exit
  • Diffuser inlet = Test section inlet
ScreenHoney combContraction coneTest sectionDiffuserSafety netFanInletExit1005080Airflow direction →

Based on Flow Speed 
​(Mach Number)

Beauty Treatment
Beauty Treatment
Skin &amp; Foot
Hair &amp; Facials
Aromatherapy
Beauty Treatment
(a) Low-Speed Wind Tunnel

  • Incompressible flow assumption

  • Applications: Lift, drag, flow visualization, UAVs, automobiles, buildings

    • M < 0.3
    (b) Subsonic Wind Tunnel

  • Compressibility effects begin

  • Applications: Aircraft wings, airfoils, control surfaces

    • 0.3 < M < 0.8
    (c) Transonic Wind Tunnel

  • Shock waves + subsonic/supersonic regions

  • Applications: Commercial aircraft, fighter aircraft design

    • 0.8 < M < 1.2
    (d) Supersonic Wind Tunnel

  • Uses convergent–divergent (C–D) nozzles

  • Applications: Missiles, rockets, high-speed aircraft

    • 1.2 < M < 5
    (e) Hypersonic Wind Tunnel

  • Very high temperature and pressure effects

  • Applications: Space vehicles, re-entry vehicles, scramjets

    • M > 5
    Beauty Treatment
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Skin &amp; Foot
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hair &amp; Facials
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Aromatherapy
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30

    Based on Circuit Type

    Beauty Treatment
    Beauty Treatment
    Skin &amp; Foot
    Hair &amp; Facials
    Aromatherapy
    Beauty Treatment
    (a) Open-Circuit Wind Tunnel (Eiffel Type)

  • Air enters from atmosphere and exits back

  • Lower cost, simple construction

  • Disadvantages: Noise, less flow control

    • (b) Closed-Circuit Wind Tunnel (Prandtl Type)

  • Air recirculates in a closed loop

  • High efficiency, better flow quality

  • Used in: Research laboratories and aerospace R&D

    • Beauty Treatment
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Skin &amp; Foot
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hair &amp; Facials
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Aromatherapy
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30

    Based on Purpose / Application

    Beauty Treatment
    Beauty Treatment
    Skin &amp; Foot
    Hair &amp; Facials
    Aromatherapy
    Beauty Treatment
    (a) Aerodynamic Wind Tunnel

  • Measures lift, drag, pitching moment

  • Used for aircraft, UAVs, missiles

    • (b) Structural / Boundary Layer Wind Tunnel

  • Simulates atmospheric boundary layer

  • Applications: Tall buildings, bridges, chimneys

    • (c) Environmental Wind Tunnel

  • Simulates wind, rain, snow, dust

  • Applications: Vehicles, trains, wind comfort studies

    • (d) Industrial Wind Tunnel

  • Product testing and optimization

  • Applications: Cooling systems, fans, turbines

    • Beauty Treatment
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Skin &amp; Foot
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hair &amp; Facials
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Aromatherapy
    Hot Stone Therapy

    This is a great place to let your visitors know who you are.

    $30
    Body Massage

    This is a great place to let your visitors know who you are.

    $30
    Skin Therapy

    This is a great place to let your visitors know who you are.

    $30
    Hot Wax Therapy

    This is a great place to let your visitors know who you are.

    $30
    Pedicure & Manicure

    This is a great place to let your visitors know who you are.

    $30
    Nail Care

    This is a great place to let your visitors know who you are.

    $30
    5.2 Wind Tunnel Techniques

    Wind Tunnel measurements

    • Velocity & Pressure
    • Forces & Moments
    • Flow Visualization & Turbulence

    Velocity & Pressure Techniques:

    Pitot tubes/Pressure Transducers: Measure static and dynamic pressure to find air speed.

    Pressure Taps: Small holes on surfaces connected to manometers or scanners for detailed pressure maps.

    Pressure-Sensitive Paint: Changes fluorescence to show pressure distribution.

      Forces & Moments Technique:

    • Force Balances: Mount models and measure lift, drag, side forces, and moments (pitch, roll, yaw).
    • Lift/Drag Coefficients: Calculated from forces, velocity, air density, and model area.

      :

      • Flow Visualization Techniques:

      • Tufts: Yarn tufts attached to surfaces show airflow direction and separation.
      • Particle Image Velocimetry (PIV): Tracks particles in the flow to map velocity fields (not explicitly detailed but a common advanced technique).

      Turbulence Techniques:

      • Hot-Wire Anemometry/Laser Doppler Velocimetry: Measure fluctuations in velocity (turbulent kinetic energy, Reynolds stresses).

       6 component balance of a wind tunnel

      Our six-component wind tunnel balance system enables precise measurement of drag, side force, lift force, rolling moment, pitch moment, and yawing moment.

      5.3 Wind Tunnel Measurements

      Wind Tunnel measurements

      • Velocity & Pressure
      • Forces & Moments
      • Flow Visualization & Turbulence

      Velocity & Pressure Techniques:

      Pitot tubes/Pressure Transducers: Measure static and dynamic pressure to find air speed.

      Pressure Taps: Small holes on surfaces connected to manometers or scanners for detailed pressure maps.

      Pressure-Sensitive Paint: Changes fluorescence to show pressure distribution.

        Forces & Moments Technique:

      • Force Balances: Mount models and measure lift, drag, side forces, and moments (pitch, roll, yaw).
      • Lift/Drag Coefficients: Calculated from forces, velocity, air density, and model area.

        :

        • Flow Visualization Techniques:

        • Tufts: Yarn tufts attached to surfaces show airflow direction and separation.
        • Particle Image Velocimetry (PIV): Tracks particles in the flow to map velocity fields (not explicitly detailed but a common advanced technique).

        Turbulence Techniques:

        • Hot-Wire Anemometry/Laser Doppler Velocimetry: Measure fluctuations in velocity (turbulent kinetic energy, Reynolds stresses).

         6 component balance of a wind tunnel

        Our six-component wind tunnel balance system enables precise measurement of drag, side force, lift force, rolling moment, pitch moment, and yawing moment.

        5.4 Numerical Problems
        Main Course
        Course
        Back
        Next
        Share -
        Tags -