The Effect of Passive Base Ventilation on the Aerodynamic Drag of a Generic SUV Vehicle

Max Varney; Martin Passmore; Adrian Gaylard

doi:10.4271/2017-01-1548

Sports Utility Vehicles (SUVs) typically have a blunt rear end shape (for design and practicality), however this is not beneficial for aerodynamic drag. Drag can be reduced by a number of passive and active methods such as tapering and blowing into the base. In an effort to combine these effects and to reduce the drag of a visually square geometry slots have been introduced in the upper side and roof trailing edges of a squareback geometry, to take air from the freestream and passively injects it into the base of the vehicle to effectively create a tapered body.

This investigation has been conducted in the Loughborough University’s Large Wind Tunnel with the ¼ scale generic SUV model. The basic aerodynamic effect of a range of body tapers and straight slots have been assessed for 0° yaw. This includes force and pressure measurements for most configurations. The slots generate useful, but small, drag reductions with the best configurations giving reductions in drag coefficient (C_d) of approximately 0.01, whereas the best taper configurations reduce C_d by close to 0.035. The slots also have a tendency to modify the lift.

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The Effect of Passive Base Ventilation on the Aerodynamic Drag of a Generic SUV Vehicle 2017-01-1548

SAE MOBILUS