Numerical Simulation of Irregular Surface Acoustic Wave Equation Based on Orthogonal Body-fitted Grids

We introduce an orthogonal body-fitted grid generation technique, and employ a high-order finite difference method to simulate the acoustic wave under the orthogonal curvilinear coordinate system. Compared with the rectangular grid, the orthogonal body-fitted grid can describe the rugged topography more accurately and eliminate the false scattering waves caused by ladder-like mesh effectively. Because of the orthogonality of body-fitted gird, the complicated transform and interpolation are not needed, thus improves the calculation efficiency. In this paper, perfectly matched layer (PML) absorbing boundary conditions are adopted under the orthogonal curvilinear coordinate system to eliminate the boundary reflection. The numerical calculation shows that the method can effectively eliminate the false scattering waves and improve the calculation accuracy.