Many boundary value problems like ocean wave propagation, structure vibrations and acoustics are represented by the Helmholtz equation. In this paper, we solve the Helmholtz equation using direct boundary element method (BEM) and the dual reciprocity boundary element method (DRBEM). For BEM formulation, there are two possible choices for fundamental solutions, which can lead to quite different conclusions in terms of their reliability in the frequency domain. For DRBEM formulation, it is shown that although the DBREM can correctly predict eigen frequencies even for higher modes, it fails to yield a reasonably accurate numerical solution for the problem when the frequency is higher than the first eigen frequency.
