Aerodynamic Simulation of a Parametrically Deformed Rotating Tire

<div class="section abstract"><div class="htmlview paragraph">As the automotive industry increasingly shifts toward electrification, reducing vehicle drag becomes crucial for enhancing battery range and meeting consumer expectations. Additionally, recent regulations such as WLTP can require car manufacturers to provide reliable drag data for vehicles as they are configured, as is the case in Europe. Vehicle and tire manufacturers can assess tire impacts on vehicle performance through testing. However, to improve designs, it is essential to identify which tire features influence the flow field and overall vehicle performance. Physical tests measure tire behavior under load, but isolating contact patch and tire bulge effects is difficult, as both change together. Simulation allows independent analysis of these factors—something that physical testing alone cannot achieve.</div><div class="htmlview paragraph">This paper investigates the aerodynamic impact of realistic tire deformation parameters—specifically, bulge and contact patch deformations—using PowerFLOW® from Dassault Systèmes ®, a Lattice Boltzmann Method (LBM) based CFD solution with an Immersed Boundary method (IBM) to model a deformed rotating treaded tire. The standalone tire setup used in this study was validated against experimental results in prior research. To further assess the impact of these deformations on vehicle drag, simulations were repeated using the generic automotive DrivAer model. Given the complexity of the flow features in a tire wake, the study employed a combination of analysis methodologies, including Principal Component Analysis (PCA) and a vortex tracking algorithm based on the Gamma 2 criterion and single-link hierarchical clustering.</div><div class="htmlview paragraph">The results demonstrate that bulge deformations tend to have a strong wake interaction with the vehicle ultimately affecting its drag, while contact patch deformations can show either purely local effects on the tire or a more complex mix of both local effects and wake interactions.</div></div>