Abstract
In the previous paper, an approximate numerical method for three-dimensional problems of Helmholtz Equation is presented. In the method, the collocation method is applied to analytic solutions represented in the polar coordinates. In this paper, the method is applied to not only three-dimensional acoustic problems of free vibration but also those of forced vibration. Numerical results are examined by comparing with experimental results. The calculated natural frequencies of a domain with the shape of a frustum of pyramid agree with measured ones. Furthermore, the distributions of sound pressure calculated on a cross-section of the domain are very like to the measured results. Effects of sound absorption of walls cannot be neglected in actual problems. Therefore, the effects are taken into account in forced vibration problems.
