An investigation of boundary element methods for the exterior acoustic problem

This paper is concerned with the efficient determination of acoustic fields around arbitrary-shaped finite structures in an infinite three-dimensional acoustic medium. The boundary integral formulation due to Burton and Miller is used to overcome the non-existence and non-uniqueness problems associated with classical integral equation formulations of this problem. A class of numerical approximation schemes is developed and the results of applying these schemes to a number of test problems are discussed and compared. The choice of the parameters of the method is critically considered. In particular, the gains to be made, in terms of solution accuracy, by using higher-order approximations to the unknown boundary function, rather than the commonly employed piecewise constant representation, are examined in view of their additional computational costs.