Surface Noise Contributions Analysis in Wave Based Method framework for exterior radiation noise problems

The characterization of acoustic radiation patterns of internal combustion engines is a challenging task required for the purpose of effective noise reduction. In experimental investigations, the shielding technique is a methodology traditionally used for the assessment of noise radiated by different surfaces. This paper introduces a surface contribution analysis (SCA) within a wave based method (WBM) framework for the assessment of noise radiated from different vibrating surfaces of a structure. The proposed method consists in the decomposition of the boundary conditions of the WBM model, assuming the linearity of the vibrational problem associated to the generation of the vibrations on the structure surface, for which the superposition principle is valid. With SCA the noise computed on specific microphone positions (field point nodes) and the acoustic power radiated from the vibrating structure is decomposed in order to analyze the different radiation contributions of each vibrating surface of the investigated structure.