Abstract
KEYWORDS
tyre / road noise, tyre radiation, equivalent sources method (ESM), ground impedance, integral equations
ABSTRACT
Reduction of the transportation noise nuisance has become an important challenge in today’s societies. As a consequence of engine noise reduction, tyre / road contact noise is now the main source of traffic noise under normal driving conditions. In this respect, the aim of the present work is to understand and to control the mechanisms of tyre radiation by designing accurate tools to predict the tyre noise radiation over arbitrary impedance surfaces. Tyre radiation is modeled using the Equivalent Sources method. Besides low frequency limitations because of two–dimensional simplifications, this model is proved to be an accurate tool for predicting tyre noise over acoustically rigid surfaces. Ground effects induced by absorbing surfaces are only approximated. Therefore, a model for the propagation of sound due to an arbitrary order source over an arbitrary impedance plane is developed. It is mainly an alternative to integral equation methods. Comparison with horn effect sound amplification indicates that this model is accurate for homogeneous as well as inhomogeneous absorbing surfaces.