A NEW ALGORITHM FOR SOLVING THE HELMHOLTZ EQUATION WITH HIGH WAVENUMBERS

摘要

This paper investigates the pollution effect, and explores the feasibility of a wavelet based local spectral method, the discrete singular convolution (DSC) algorithm for solving the Helmholtz equation with high wavenumbers. The Fourier analysis is employed to study the dispersive error of the DSC algorithm. Our analysis of dispersive errors indicates that the DSC algorithm yields a dispersion vanishing scheme. The dispersion analysis is further confirmed by the numerical results. For one- and higher-dimensional Helmholtz equations, the DSC algorithm is shown to be an essentially pollution free scheme. Furthermore, for large scale computation, the grid density of the DSC algorithm can be close to the optimal two grid points per wavelength. The present study reveals that the DSC algorithm is accurate and efficient for solving the Helmholtz equation with high wavenumbers.