A Study of Groove Pulsation Noise Reduction by Simple Aerodynamic Modelling of a Tire Rolling on Porous Pavement

The effect of road surface porosity on tire noise was investigated using a simple computational fluid dynamics model. The object of this study is the air pulsation amplitude in a tread groove placed in the circumferential direction. In this CFD simulation, the rolling tire was replaced by the wind speed distribution around a cylinder. Then, a mirror image of the tire was set on the underside of the road surface and it expressed the road surface porosity by slightly reducing the wind speed distribution around it avoiding complex shape modelling. In this way, air flows into the road surface, and the air pressure decreases slightly there eventually. As a result, the pressure difference before and after groove becomes small. Another result is that pulsation within the groove is generated when the effective cross-sectional area of the groove changes due to the roughness of the road surface. According to simple calculation, the sound source intensity due to this pulsation is stronger than that caused by mono-pole sources at the groove entrance due to surface unevenness. This study confirmed that porous pavement decreases tire groove pulsation noise by reducing static pressure difference between the leading and trailing entrances.