Prediction of the characteristic of sound fields in long enclosures by a hybrid computer model

Abstract

A combined ray tracing and image source model RATISM has been developed specially for the simulation of sound propagation throughout long enclosures such as a corridor. How the algorithm models sound source, sound propagation, and sound receiver was described. The ways in which more complex long enclosures can be modeled were also given. The methods of the prediction of reverberation time and sound pressure level were presented in detail. Three different enclosures were modeled and the results were analyzed. The reverberation room of Northwestern Polytechnic University was measured and predicted to show RATISM can be used for both diffused and nondiffused sound field. A rectangular long enclosure was then predicted by RATISM and NORMAL [L. N. Yang and B. M. Shield, J. Sound Vib. 229, 133–146 (2000)] and the comparison showed that both the two models can correctly simulate the sound field in rectangular long enclosures. A more complicated long enclosure was also simulated and the results showed that the sound field in it had similar characteristic to that in the rectangular one, in which the sound field is nondiffused and sound distribution was mainly dependent on the distance of receiver to source. [Work supported by the Doctorate Foundation of Northwestern Polytechnical University.]