Abstract
Keywords: automotive aerodynamics, cross wind, base flow
As passenger vehicles becomes lighter to reduce fuel consumption, the stability and handling characteristics become more susceptible to the aerodynamic forces. And more, when running on the road, a vehicle is submitted to a non uniform turbulent atmospheric flow to transient cross wind. This phenomena, as passing or crossing manoeuvres, are factors in the vehicle´s dynamic stability (Hucho, 1998).
From an experimental angle, the cross wind effect was already studied and several techniques allow the reproduction of a side gust of wind in a wind tunnel. For Baker and Humphreys (1996), Macklin et al. (1996), it was obtained by propelling the model on a rail crossing the test section of the wind tunnel. Ryan and Dominy (1998) experimented on a generic hatchback model and used a technique where the side wind was produced by a cross jet. Another technique consists of using oscillating airfoil sections positioned upstream of a stationary model (Passmore et al., 2001). Many experimental studies of cross wind was carried out for a car model (Backer, 1991; Ryan and Dominy, 2001), for a lorry model (Backer, 1991; Gary, 1996). A few experimenters use a real car model (Howell, 1996, Özdemir and Özdemir, 2004).