ON FURTHER VALIDATION AND USE OF THE FINITE-ELEMENT METHOD TO ROOM ACOUSTICS

The present paper deals with the finite element analysis of transient vibration of air in rooms and is a sequel to earlier finite element wo rk presented by Craggs. Results obtained from the finite element model of rectangular, triangular and cylindrical rooms are compared with th ose given elsewhere in the literature. It is shown that the decay cons tants depend on the type of mode, rather than on the type of wave-axia l, tangential or oblique. However, with small patches of absorption it is shown that even for rectangular rooms no such classification exist s. Sabine's theory is shown to predict quite accurately the decay cons tants of oblique modes when the absorptive lining is distributed unifo rmly across walls which are not curved. Furthermore, results are inclu ded for irregular rooms, as well as for regular rooms where the specif ic admittance of the absorptive lining depends on the frequency of exc itation. (C) 1995 Academic Press Limited