Numerical Simulation of the Flow around the Wheel within Wheelhouse

Abstract: Increasing crude oil price and different legislation for vehicle emissions forced the vehiclemanufacturer to produce more efficient vehicles. Road vehicle aerodynamics reachesits limits, in designing of optimal upper body shapes. It has been studied that about 25percent of total aerodynamic resistance originates from the wheels. The effect of rotatingwheels exposed to a free-stream, or being partially covered by the car wheelhouse, leadsto a dramatic increase in drag and lift coefficients. Numerical simulation of flow arounda generic vehicle is used to accurately predict the flow and also to study the developmentof the flow in time. Two cases are studied, The case of simplified bus shape vehicleand a modified rectangular box shape vehicle. The results of numerical simulations for thevehicle with wheels (bus shape vehicle) were compared with the basic form (modified rectangularbox shape vehicle), the obtained result are compared with available experimentaldata of the flows around the wheels within the wheelhouse. The time-averaged computedflow is examined to reveal both flow structure and new details of flow structures knownfrom previous experiments. The mechanism of formation of the flow structures are explained.A general schematic picture of flow structure is presented. Surface pressures andforces including lift and drag forces are computed and their comparison with experimentalresults shows reliability of numerical method. This project will try to establish accuratepicture of the flow structure around vehicle wheels and also try to provide reasonableexplanations for the flow mechanisms.iv