Numerical Investigation of the Air Pumping Noise Generation Mechanism in Tire Grooves

Tire noise has been a topic of increased focus of research in industrial countries in the recent years, due to its contribution to traffic noise. However, knowledge about aerodynamic noise generation mechanisms, which are responsible for the high frequency noise in tires is lacking. This study focuses on the aerodynamic mechanism of small-scale air pumping in tire grooves, where computational fluid dynamics (CFD) is used to investigate the flow and noise features resulting from two different types of deformation in the process of a tire groove interacting with a smooth road surface. The two deformation types include (a) a commonly used piston-type motion of the bottom wall and (b) a more realistic bulging in/out of the side walls of a tire groove. The large eddy simulation (LES)-based approach consisting of the filtered Navier–Stokes equations is employed here along with the appropriate boundary conditions to accurately calculate the solution of the fluid flow resulting from the compression and expansion of air in the groove. Flow patterns are analyzed using velocity and pressure field data, whereas noise analysis is carried out using temporal pressure profiles and corresponding frequency spectra. The comparative study presented here provides a better understanding of the small-scale air pumping phenomenon in tire grooves and also demonstrates the significance of the choice of deformation type employed in such numerical simulations. The latter is critical in designing a more complete CFD model, which can further be used to optimize the tire acoustics.