Transient Tyre Noise Measurements Using Time Domain Acoustical Holography

Localization and ranking of sound radiating regions on tyres under transient conditions is very difficult both because of the transient nature and because it is difficult to measure sufficiently close to the sound radiating regions. Using Near-field Acoustic Holography it is possible to measure at some distance and then extrapolate back to the surface of the tyre. With the Time Domain Acoustical Holography it is further possible to study the transient nature of the sound generation in any desired detail. As an example, the present paper compares the sound radiation under stationary and under accelerating conditions.