Effects of Wheel Configuration on the Flow Field and the Drag Coefficient of a Passenger Vehicle

Journal article, 2019

The effects of wheel rotation, rim coverage area, fan spokes, spoke sharpness, and tread pattern on the flow field and drag coefficient of a passenger vehicle were investigated. Force measurements and wake surveys were taken on a 1/5th scale passenger vehicle at a Reynolds number of 2.0 × 106. The wake surveys were conducted at three planes. Vorticity, total pressure coefficient, and local drag coefficient plots are presented. Wheel rotation reduced the drag coefficient of all of the wheel configurations tested, which generally agrees with literature. Wheel rotation reduced the front wheel’s jetting vortex’s drag while increasing the drag from the center of the front wheel to the upper rim track. Reducing the rim coverage area increased the drag coefficient. This increase was attributed to an increased jetting vortex drag and a change in flow separation around the front wheel. The fan spoke rim performed the worst, regardless of rotation. Rounding the spoke edges reduced the drag coefficient of a rotating wheel. The tread pattern slightly reduced the shoulder vortex vorticity and slightly increased the separation around the front wheel.