ASA 124th Meeting New Orleans 1992 October

3pSA2. Acoustic harmonic radiation from cylinders using a new internal source density method.

Peter R. Stepanishen

Sudheer Ramakrishna

Dept. of Ocean Eng., Univ. of Rhode Island, Kingston, RI 02881

Two-dimensional acoustic harmonic radiation from cylinders which are symmetric about an axis and vibrating with a specified normal velocity is addressed using a new internal source density approach. The approach is based on the use of internal monopole and dipole source density line distributions along the axis of symmetry of the cylinder. A least-mean-square error method is used to determine the source distributions by matching the normal velocity of the cylinder to the normal velocity field of the source distributions at the cylindrical surface. The surface pressure and exterior pressure field are readily obtained from the source distributions. Discretization of the resultant line integrals leads to sets of linear algebraic equations which are readily solved for the monopole and dipole source strengths. Numerical results are presented to illustrate the accuracy of the method for the case of circular and elliptical cylinders subjected to various specified continuous and discontinuous normal velocity boundary conditions and frequencies.