The Impact of the Wheel’s Rim on the Aerodynamics of Passenger Vehicles

The purpose of this Paper is to investigate the amount of aerodynamic energy consumed by the wheels and the impact on the overall drag of a passenger vehicle. The wheel parts (rim, tire and cap) were modeled and aerodynamically analyzed using a finite element Computational Fluid Dynamics (CFD) software. To highlight the wheel’s potential in the overall aerodynamic drag the rim’s useful area is modified by decreasing the porosity in a progressive manner. The CFD simulation results are presented using Iso-Lambda and Iso-Cpi, parameters together with coefficients like total pressure deficit, skin friction and vorticity magnitude. An important conclusion of the study was the fact that by blocking the flow thru the rim, an aerodynamic potential can be achieved. Careful design of wheels may lead to significant reduction in drag and improvements of vehicle drag coefficient. This would generate lower fuel consumption and important CO2 reduction, leading to a more environmentally friendly vehicle. The work will be continued by extending the analysis towards commercial vehicles like heavy trucks that have a significant number of wheels and are more exposed to air flow. Improvements in this area may lead to a significant reduction in fuel consumption. It should be pointed out that CFD is a good method for developing and optimizing solutions but has to be reinforced by physical tests performed on road or in wind tunnels.