Analysis and Design of Automobile Forebodies Using Potential Flow Theory and a Boundary Layer Separation Criterion

An effective method of designing low drag, attached flow automobile forebodies has been developed. Based on a potential flow panel method, a series of computer programs is used to define idealized pressure gradients at several forward corner locations including the hood, fender, windshield header and A-pillar. Idealized pressure gradients for several radii at each corner location are analyzed using a turbulent boundary layer separation criterion to determine if real-world viscous flow will remain attached. Correlation with wind tunnel test results is included. A non-circular, attached flow hood corner shape is developed based on the separation criterion and an inverse (geometry defining) computer method.