Investigation of Wheelhouse Flow Interaction and the Influence of Lateral Wheel Displacement

Abstract

The aim of this research was to improve the understanding of the complex flow featuresfound around a wheel and wheelhouse and to examine how the lateral displacement of the wheelaffects these features and the production of exhibited pressures and forces. A bespoke rotatingwheel rig and accompanying wheelhouse with a fully-pressure-tapped wheel arch was designedand manufactured at Loughborough University. Wind tunnel tests were performed where force andpressure measurements and Particle Image Velocimetry (PIV) data were obtained. The experimentaldata was used to validate unsteady CFD predictions where a k-! SST Improved Delayed DetachedEddy Simulation (IDDES) turbulence model was used in STAR-CCM+ (10.04.009, Siemens). The CFDshowed good agreement with all trends of the experimental results providing a validated numericalmethodology. For both methodologies, a lower amount of wheelhouse drag was found generatedwhen the wheel was rotating. However, the CFD showed that whilst this was the case, totalconfiguration drag had increased. This was attributed to an increase of the wheel and axle drag,illustrated by the change in separation over the wheel itself when located within a wheelhouseand so overcompensating the reduction in body and stand drag. Differences in vortex locationswhen comparing to previously-attained results were due to differences in housing geometry, suchas blockage in the cavity or housing dimensions. Experimental and computational results showedthat up until a 10 mm displacement outboard of the housing, overall drag decreased. The reductionin housing drag was credited to a reduction in the size of outboard longitudinal vortex structures.This led to the lateral width of the shear layer across the housing side being narrower. Overall, thisstudy identified that there were potential benefits to be gained when offsetting a wheel outboard ofthe longitudinal edge of a model housing.