Dispersion analysis for the finite element algorithm in acoustic wave equation numerical simulation
Yin Xingyao
Zhou Jianke
Wu Guochen
Liang Kai
Abstract：This paper focuses on the dispersion problems of finite element algo-rithm in numerical simulation of seismic wave,and the dispersion function of two-dimensional acoustic wave equation is derived by employing lumped mass matrix and bilinear interpolation finite element algorithm.And,we compared quantitatively the effect of incident direction with the variable ratio of vertical to horizontal grid,spatial sampling interval,seismic wave frequency,and forma-tion velocity on numerical dispersion.The numerical examples and the forward modeling indicate,if we want to suppress the numerical dispersion effectively, it should not be less than 20 samples within the wavelength corresponding to peak frequency of source wavelet;reducing the ratio of vertical to horizontal grid can suppress the numerical dispersion with small incident angle (the angle between the direction of wave propagation and the z axis)remarkably;the slo-wer the propagation velocity of the seismic wave with higher frequency,the more serious its dispersion is;when the ratio of phase velocity to the corre-sponding frequency is less than twice of spatial sampling interval,not only the numerical dispersion becomes very serious,but also the aliasing phenomenon will happen.
Keywords：bilinear interpolationfinite element methodacoustic wave equa-tionlumped mass matrixnumerical dispersion
Publication Date：2014-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：12( 944-955 )