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An empirically-based prediction method for car aerodynamic lift and side forces
Published July 18, 1994 by Royal Aeronautical Society in United Kingdom
Event: Vehicle Aerodynamics
Following a similar approach to that used in the earlier MIRA Drag Prediction Method, an empirically-based method has been devised for estimating, from dimensional parameters, aerodynamic lift and side forces experienced by cars and light vans.
In order to identify, and then quantify, the parameters with significant influence on lift and side forces, MIRA's existing data-base was extended to include data from the relevant literature, together with new data from a substantial program of wind-tunnel measurements carried out specifically for this project.
The data-base consists mainly of wind-tunnel measurements on variable- geometry models. From these, empirical relationships have been derived to allow front, rear and total lift coefficients (at zero yaw angle) and side force and yawing moment coefficients to be predicted from the selected vehicle dimensional parameters. The development of these relationships is detailed in this paper. A computer program has been written into which these empirical relationships have been incorporated.
Validation of the resulting prediction method against wind-tunnel data for a wide range of vehicles has shown a fairly good correlation between predicted and measured force and moment coefficients. The need for further refinement of the method is recognized, however, in order to realize its full potential as a design tool