Wind Tunnel Testing

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 Wind Tunnel Testing


Introduction
To study the vehicle aerodynamics, wind tunnels is one of the methods used to study the properties of moving air and the interaction between the air and solid bodies moving through it. A wind tunnel is a large hollow tube, with powerfull fans that generates a flow of air inside the tunel which allows the study of the forces acting on the case model. Most vehicle manufactures use wind tunnels to test designed prototypes in order to study and optimization of the airflow around the surface of the vehicle.
Wind tunnels are classified by the amount of speed it can produce, which are:
  • Low Subsonic;
  • Transonic;
  • Supersonic;
  • Hypersonic.
Advantages 
Quiet operation vs open return tunnel; low cost operation; capable for uniform flow test.
Disadvantages
Size and motion limitation; wind tunnel inner walls influences the flow; high installation cost; environment influence.

The type of wind tunnel available in the university is a subsonic wind tunnel (750mm diameter).
For this testing case, a 3D model Aston Mini was used. This testing is to improve the airflow around the vehicle body, to achieve it, 3D printed models was designed and printed.

Wind Tunnel list of apparatus and instrumentation:
  • Subsonic wind tunnel (750mm diameter);
  • Barometer (mercury);
  • DC Power Supply (Model: TPS-2000);
  • Pitot Tube;
  • Wrench (10mm);
  • Inclined Manometer;
  • Anemometer (Testo 416);
  • Single Point Load Cell;
  • Multimeter (Black Star 4503 Intelligent multimeter);
  • Stand and Clamps;
  • Fog Machine.
Wind Tunnel Diagram
Austin Mini 3D model Scan

3D printed model design parts
Front
 Side Fins

 Rear Wing

Parts Assembled (3D scan)

Parts Assembled
 

Results

Initial conditions
Ambient Temperature = 16°C
Air Pressure (KPa) = 101.325 KPa
Load Cell Initial Force (@ 0 m/s) = -1.79V
Length of the Vehicle (m) = 0.256m
Area of the vehicle (m/s2) = 0.0972m/s2
Density of Air (kg/m3) = 1.225 kg/m3
Gas Constant (J/Kg.K) = 287J/Kg.K
Viscosity of Air (Pa.s) = 0.0000181 Pa.s
Gravity (m/s2) = 9.81 (m/s2)

Lift Force vs Load Cell Force
Result 1 (Before modifications)

Lift Force vs Load Cell Force
Result 2 (After Modifications)



Last Update: 14/11/2022

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