Effect of Unsymmetrical Wind Incidence on Aerodynamic Forces Acting on Vehicle Models and Similar Bodies 650136
Unless conditions happen to be windless or unless wind direction is parallel with the vehicle course, the wind acting on a vehicle will approach from a variety of angles relative to the longitudinal axis. This unsymmetrical incidence causes an aerodynamic force which is generally applied at some distance from the center of gravity and thereby also sets up a moment. As far as directional stability is concerned, it is the component acting transversely to the longitudinal axis of the vehicle and its moment about the vertical axis which are of special interest.
Accidents in which there are no technical defects or negligence on the driver’s part to account for the vehicle leaving the road at high speed can, in many cases, definitely be attributed to the action of strong, gusty side winds, and to the unstable properties of the vehicle shape. From this it is concluded that the effect of side wind merits examination not only in regard to racing and sports cars, but also mass produced models. Fundamental wind tunnel investigations of rectangular objects and vehicle models are intended to throw light on these phenomena.
This paper discusses vehicle model tests and the action of stabilizing fins, the effect of Reynolds number, and measurements of pressure distribution.