Prediction of sound pressure in the far field using the inverse boundary element method

The inverse boundary element method (BEM) is a numerical procedure whereby sound pressure measurements in the near field are used to predict the vibration on a vibrating surface. After the vibration on the surface (or particle velocity in the case of an opening) is determined, the sound pressure in the far field can be predicted using a forward BEM analysis. This paper will examine the applicability of the inverse BEM to predicting sound pressure in the far field on two examples; an engine cover and generator set. The results indicate that the inverse BEM can be used to accurately predict far field sound pressure. Additionally, it is demonstrated that a partial or patch BEM model of a surface can be utilized successfully in some instances as a means of reducing the computation time.