Evaluations of Shape Parameter of Groove for Reducing Noise Generated From Rotating Tires

Abstract

Acoustic fields obtained by large-eddy simulations around a rotating tire with the grooves are investigated to clarify the relationships between the shape parameters of the grooves and the directivity of noise sound. To acquire acoustic field around the rotating tire, the large-eddy simulations using the sixth-order compact finite difference scheme and the tridiagonal filter are performed. The sixteen cases including the non-groove case are considered in the present study. To evaluate the acoustic noise from the groove, the sound pressure level (SPL) of each point is computed, and the difference between the cases with and without the groove is investigated. The obtained Results indicate that the width at the opening side of the groove strongly impacts on the acoustic field, and the acoustic noise is reduced as the width at the opening side increases. Additionally, the acoustic noise is reduced as the width at the bottom side increases. However, the depth and the area of the groove do not have a strong relation to the acoustic field. In the viewpoint of the noise directivity, larger the widths at the opening side and the bottom side, and the angle between the bottom and the side wall reduce the acoustic noise on the side of the rotating tire, while that in front of the tire increase. These results provide new insight into our understanding the mechanism of noise generated from the rotating tire with grooves and may help to make intelligent design for noise reduction.