Aerodynamic interaction of a front and rear wheelhouse for a generic vehicle

Wheels produce key flow structures that contribute up to 30% of a vehicle's drag, limiting range and increasing emissions. The jetting vortices produced by the front wheels have been demonstrated to contribute greatly to the drag of a vehicle. Studies concerning wheels within a wheelhouse have often neglected the impact of the rear wheel and how the flow structures from the front wheel influence those generated at the rear. A numerical investigation was undertaken that utilised a modified Fabijanic body that included rear wheels. Variations in wheel spacing, front and rear overhang were evaluated that demonstrated these were critical geometric parameters that could vary the total vehicle lift and drag in excess of 100% and 15% respectively. Rear wheelhouse vortices displayed distinctive changes to those produced at the front wheel and were sensitive to wheel spacing. These changes were driven by the outboard jetting and inner wheelhouse out flow vortices which would suppress vortex formations at the rear wheel, manipulating the flow field and resulting in a signicant change in overall drag force. Variations in wheel spacing and front overhang have demonstrated the signicant impact of the front wheel flow structures on the rear wheel flow field and can be manipulated to reduce vehicle drag.