Effects of Domain Boundary Conditions on the CFD Prediction of Flow over an Isolated Tire Model

Tire modeling has been an area of major research in automotive industries as the tires cause approximately 25% of vehicle drag. With the fast-paced growth of computational resources, Computational Fluid Dynamics (CFD) has evolved as an effective tool for aerodynamic design and development in the automotive industry. One of the main challenges in the simulation of the aerodynamics of tires is the lack of a detailed and accurate experimental setup with which to correlate. In this study, the focus is on the prediction of the aerodynamics associated with an isolated rotating Formula 1 tire and brake assembly. Literature has indicated differing mechanisms explaining the dominant features such as the wake structures and unsteadiness. Limited work has been published on the aerodynamics of a realistic tire geometry with specific emphasis on advanced turbulence closures such as the Detached Eddy Simulation (DES). In this study, we take a deeper look at the wake characteristics of an isolated tire model using CFD and compare it to the Particle Image Velocimetry (PIV) data on a Formula 1 tire model tested by Stanford University. The effects of domain size on the aero characteristics of the tire will be studied to provide a deeper insight into the influence of different boundary conditions at the domain walls. The impact on the characteristics and unsteady motion of the wake structure of the tire model is presented.