Fourier expansion-based differential quadrature and its application to Helmholtz eigenvalue problems

Based on the same concept as generalized differential quadrature (GDQ), the method of Fourier expansion-based differential quadrature (FDQ) was developed and then applied to solve the Helmholtz eigenvalue problems with periodic and non-periodic boundary conditions. In FDQ, the solution of a partial differential equation is approximated by a Fourier series expansion. The details of the FDQ method and its implementation to sample problems are shown in this paper. It was found that the FDQ results are very accurate for the Helmholtz eigenvalue problems even though very few grid points are used. (C) 1997 John Wiley & Sons, Ltd.