Tyre/road noise mainly consists of two parts, air-pumping noise and noise created by vibrations of the tyre surface. Air-pumping is a collective concept for noise created directly in the contact between tyre and road. There are a number of suggested generation mechanisms for air-pumping noise but no general theory that can explain and predict the phenomena for all combinations of tyre, road and vehicle speed. This project attacs air-pumping from a different angle - the vehicle speed dependency of different types of noise sources. We assume that air-pumping noise is
generated by monopole type of sources (similar to small, pulsating spheres). Then the sound pressure level caused by air-pumping must have a vehicle speed exponent around 4. In other words, the sound pressure level will be proportional to U4, where U is the vehicle speed. The, so far, better understood generation mechanism, tyre vibrations, have a U2 dependency. By analysing the speed exponent of tyre/road noise, the proportion of the two different components can be identified. This powerful tool allows for advanced investigations of the air-pumping phenomenon with the goal to understand how it can be predicted.
Influence of air-flow related sources to the total tyre/road
noise for a slick tyre rolling on a rough road surface.
The project is carried out at the Division of Applied Acoustics in the research group Vibroacoustics.
More information can be found at Leisstras homepage.
Keywords: tyre/road noise, air-pumping
Projectleader
Thomas Beckenbauer (Müller BBM GmbH)
Project members
Julia Winroth
Wolfgang Kropp
Carsten Hoever
Müller BBM GmbH (Projektleitung)
Chalmers University of Technology
Continental Reifen Deutschland GmbH
Karlsruher Institut für Technologie
Built Environment
Transport