Development of a blocked pressure criterion for application of the principle of acoustic reciprocity

The principle of acoustic reciprocity can be applied in practice to estimate the sound radiation of a vibrating surface, from an inverse measurement of the Green function. This principle is especially useful in evaluating and ranking the sound radiation from individual vibrating components of a complex mechanical system. Usually, a blocked pressure assumption is needed in order to simplify the formulation of the reciprocity technique. This paper examines the validity of the blocked pressure hypothesis in the context of the reciprocity method, and suggests a "blocked pressure criterion" to rigorously quantify the impact of this hypothesis on the sound radiation prediction. This criterion is tested numerically on a system consisting of two coplanar, simply supported thin baffled plates that are mechanically uncoupled. It is shown that the numerical results support the conclusions obtained from the blocked pressure criterion. (C) 2001 Academic Press.