CFD Investigation of the Effect of the Salient Flow Features in the Wake of a Generic Open-Wheel Race Car

Abstract

It is well known that in motorsport the wake from an upstream vehicle can be detrimental to the handling characteristics of a following vehicle, in particular in formulae with high levels of downforce. Previous investigations have been performed to characterize the wake from an open wheel race car and its effect on a following car, either through the use of multiple vehicles or purpose-built wake generators. This study investigates how the wake of an upstream race car impacts the aerodynamic performance of a following car in a close-following scenario. Wakes are imposed on the inlet of a CFD simulation and wake parameters (eg: velocity deficit, trailing vorticity) are directly manipulated to investigate their individual impacts on the following vehicle. The approach provides a useful alternative to the simulation of multi-vehicle cases but a better simulation could be achieved by including wake unsteadiness from the upstream vehicle. Arguably the most significant impact of a wake on the following vehicle was found to be the rearward movement of the vehicle center of pressure. Secondary flow (eg: upwash, vorticity) on a bulk scale had the beneficial impact of moving the wake up and over the following vehicle but more localized impacts could be positive or negative according to the detailed interaction with downstream vehicle features.