Computation of acoustic propagation in non-homogeneous unbounded medium by DRBEM

We present here an extension of the boundary element method, the DRBEM (Dual Reciprocity Boundary Element Method), in order to solve the Helmholtz equation governing the propagation of linear acoustic waves in apr unbounded variable mean temperature medium at rest. The originality of the method is that it allows discretization and integration only on the boundary of the domain, without an inner grid The method is used here to study the wave propagation inside a non-isothermal flanged cavity, and throughout a thermal flume without mean velocity expending in a medium of constant outer temperature. (C) Academie des Sciences/Elsevier, Paris.