Analysis of Aerodynamic Characteristics of Fan-Type Wheels

Abstract

<div class="section abstract"><div class="htmlview paragraph">This research addresses the pressing need for reducing vehicle aerodynamic resistance, with a specific focus on mitigating wheel and tire resistance, which constitutes approximately 25% of the overall vehicle drag. While the prevailing method for reducing resistance in mass production development involves wheel opening reduction, it inadvertently increases wheel weight and has adverse effects on brake cooling performance. To overcome these challenges, novel complementary resistance reduction methods that can be employed in conjunction with an appropriate degree of wheel opening reduction are imperative. In this study, we introduce symmetrical wheels with a fan-like shape as a solution. The fan configuration influences the surrounding flow by either drawing it in or pushing it out, depending on the direction of rotation. Application of these fan-type wheels to a vehicle's wheels results in the redirection of flow inwards or outwards during high-speed driving due to wheel rotation. This, in turn, impacts the vehicle's rear wake deformation and, consequently, induces alterations in vehicle aerodynamic performance. The study begins by introducing the designs of fan-type wheel covers that can be mounted on the base rim. We evaluate the ventilation (suction-blowing) performance of these wheels and their impact on the vehicle's aerodynamic performance through wind tunnel tests. Detailed numerical analysis of the flow field within the wheel cover and around the vehicle, resulting from the rotation of these fan-type wheels, is carried out using Computational Fluid Dynamics (CFD) simulations. These simulations utilize the Moving Reference Frame (MRF) method to simulate wheel rotation.</div></div>