Speron 2020 - A tool for predicting the acoustic performance of road surfaces (Leisstra 3, part project 1)

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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

• Wolfgang Kropp

  Full Professor/Research Group Leader, Architecture and Civil Engineering, Applied Acoustics, Vibroacoustics

  Wolfgang Kropp is a professor at the division of applied acoustics, and deputy head of the department of architecture and civil engineering and vice head, research. He is also the head of the...