ASA 124th Meeting New Orleans 1992 October

4pSA5. Prediction of acoustic radiation using analytical/numerical matching.

Donald B. Bliss

Linda F. Peretti

Dept. of Mech. Eng., Duke Univ., Durham, NC 27706

Analytical numerical matching (ANM) is a hybrid method that forms a composite solution by combining a low-resolution global numerical solution, a high-resolution local solution, and a matching solution. ANM is a novel method to obtain accurate numerical solutions with high spatial resolution for low computational cost. ANM has been successfully applied to a variety of problems in aerodynamics and vortex dynamics, and is now being applied to problems in acoustics and structural dynamics. The present work illustrates the application of ANM to acoustic radiation. A vibrating surface with sharp discontinuities is placed at the end of a channel. The problem is solved approximately using ANM and compared to the exact solution. In the ANM approach, the sharp discontinuity is intentionally smeared for the global solution, which can then be calculated by efficient low-resolution means. The effect of the discontinuity is handled by the high-resolution local solution, which is solved independently of the geometry of the global problem. The results show the ANM approach to be accurate and dramatically more efficient. Extensions of ANM to more general problems in structural acoustics with sharp discontinuities are discussed. [Work supported by ONR.]