A discontinuous Galerkin seismic wave simulation algorithm for complex fluid-solid media based on triangular cell and velocity stress equation
The discontinuous Galerkin method(DG)can be used with models of complex geometry boundaries,and also has the advantages of higher-order accuracy and easy parallel computation,thus has been developed rapidly for seismic wave propagation simulation in recent years.Numerical flux is one of the key components of DG.Compared with other fluxes,Rankine-Hugoniot(RH)condition flux has better stability regions at the interface between solid and fluid media and can use a larger time step,especially when the wave impedance contrast between the solid and fluid is large.It has been used to simulate seismic wave propagation in fluid-solid media using the quadrilateral mesh and the velocity-strain equations.In this study,for simulating seismic wave propagation for natural reservoirs on land with complex shape of the fluid-solid interface and for coupling with other numerical methods in the future,the discontinuous Galerkin method based on RH-condition flux and triangular mesh is developed for seismic wave simulation in complex fluid-solid media using the velocity-stress equations for both acoustic and elastic media.The accuracy of the simulation is verified by the horizontal layered and sin-type fluid-solid models.The numerical simulations show the accuracy and efficiency of the proposed DG with different mesh sizes and orders.Finally,an example of the complex model is given to show that the method can accurately apply the fluid-solid boundary conditions in the presence of complex fluid-solid interfaces.
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