Wind Tunnel
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Introduction
Aerodynamic Theory
Wind Tunnel
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Wind Tunnel
Used to study the aerodynamic properties of an object in a stationary manner
Motion is simulated by moving air (fluid) around the object of interest
Properties measure in wind tunnel include pressures, forces, velocities, and vibrations
Wind tunnel studies are not 100% accurate
Wind tunnel pictorials:
Types of Wind Tunnels
- A basic wind tunnel (open-circuit)
- General Motors’ wind tunnel (close-circuit)
- Open-circuit wind tunnels
- Less expensive
- Subject to ambient conditions
- Require more power
Close-circuit wind tunnels
- Avoids loss of return air’s momentum
- Constant ambient conditions
- Expensive
A wind tunnel can not always simulate road conditions, e.g.,
- Ground effect
- Tire rotation
- Reynolds number (scale corrections)
- Wall interference
- Natural variations in ambient conditions
- Challenges
- Model size
- The larger, the greater the wall effect
- The smaller, the less accurate
- Simulation of the moving
road
- Mounting of model and rotating wheels
- Examples of wall effect corrections
- Simulation of moving ground
- Important issue about wind tunnel studies,
- Understanding the aerodynamic problem is more critical than sensitive
instrumentation
- Whatever works satisfactorily in the wind tunnel, will usually work well
on the road
- Scale model studies are usually too conservative, and the vehicle can be
further optimized
TEC452 Home
Aero Index
Introduction
Aerodynamic Theory
Wind Tunnel
Computational Fluid Dynamics
Vehicle Aerodynamics