Experimental investigations into the air pumping effect at the tyre/road interface

Introduction: Environmental noise pollution is an important issue that affects health and quality of life of millions of people in the modern world. One of the main sources of environmental noise pollution is the noise generated by road traffic. To reduce road traffic noise, the automotive industry has done a great deal of research and development in the recent decades. As a result of these efforts, such earlier important contributors to the overall automotive noise, as powertrain and exhaust noise, have been reduced considerably for nearly all driving conditions, so that the dominant contributor has become tyre/road noise. According to the tyre/road noise reference book written by Sandberg and Ejsmont, there are two different groups of generation mechanisms for tyre/road noise: (i) tyre vibrations; and (ii) aerodynamical effects in or around the tyre. In contrast to noise generated by tyre vibrations, the aerodynamical mechanisms of tyre noise generation have received relatively little attention in the past. Therefore, the main aim of the research reported in this paper was to undertake comprehensive experimental investigations of aerodynamically related mechanisms of tyre/road noise.