Noise source characterisation using patch impedance technique

A novel approach of an environment-independent sound source characterisation is discussed. The source is defined via a suitable enveloping interface surface by its blocked sound pressure and its surface impedance. Both the blocked pressure and the impedance are discretised using the averaging patch concept. Such a definition avoids singularity of point acoustic impedance and is suitable for numerical as well as experimental implementation. The characterisation of a source by the patch concept allows for the acoustical sub-structuring, which in turn enables the prediction of the sound field created by the source coupled to an arbitrary environment. Numerical simulations are presented which demonstrate the feasibility of the approach. It is hoped that the proposed approach can serve as a universal tool for noise synthesis of complex equipment incorporating noise sources.