Revised finite sound ray integration method based on Kirchhoff's integral equation.

Abstract

This thesis explains the calculation theory of a revised finite sound ray integration method and the algorithm based on the integration equation, which is obtained by the solution of Kirchhoff, from the wave equation. It also explains the calculation of small rectangular space pulse response by using the revised finite sound ray integration method, and correspondence of the values with model test values. The theoretical equation which is the basis of this calculation method is the transformed equation of Kirchhoff's integration equation, that is assuming a point source of sound without dimensions. In order to calculate this equation, the integral domain on the boundary surface, which changes in accordance with the lapse of time, and the sound wave propagation distance, etc. have to be obtained. We, therefore, simulated the spherical progressive wave by utilizing a multiple number of sound rays, which were radiated from the sound source at equal solid angle, and then obtained the various necessary information for the calculation. Up to this time, the said calculation method is programmed on the condition that the pursuing sound rays are only mirror reflecting sound rays, and a small computer can be used for the calculation. When we measured the pulse response by using a 1/4 scale rectangular room model, which was composed of complete reflecting surfaces and a complete sound absorbing surface, and the results were compared with the calculation values by the revised finite sound ray integration method, we were able to obtain very reasonable results.