3D Seismic Wavefield Modeling in Generally Anisotropic Media with a Topographic Free Surface by the Curvilinear Grid Finite‐Difference Method

2018 ◽  
Vol 108 (3A) ◽  
pp. 1287-1301 ◽  
Author(s):  
Yao‐Chong Sun ◽  
Wei Zhang ◽  
Xiaofei Chen
Keyword(s):  
Free Surface ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Anisotropic Media ◽  
3D Seismic ◽  
Curvilinear Grid ◽  
Seismic Wavefield

2-D poroelastic wave modelling with a topographic free surface by the curvilinear grid finite-difference method

2019 ◽  
Vol 218 (3) ◽  
pp. 1961-1982 ◽  
Author(s):  
Yao-Chong Sun ◽  
Hengxin Ren ◽  
Xu-Zhen Zheng ◽  
Na Li ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Free Surface ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Wave Modelling ◽  
Curvilinear Grid

Simulation of the Seismic Response of Two Different Thick Deposition Layers with Hybrid PSM/FDM Method

2013 ◽  
Vol 353-356 ◽  
pp. 1858-1866
Author(s):  
Wu Jian Yan ◽  
Yu Cheng Shi
Keyword(s):  
Finite Difference ◽  
Finite Difference Method ◽  
Ground Motion ◽  
Difference Method ◽  
Strong Ground Motion ◽  
Pseudospectral Method ◽  
Wavefield Simulation ◽  
The Finite Difference Method ◽  
Seismic Wavefield ◽  
Strong Ground

In this paper, we simulated two-dimension numerical on the strong ground motion through the hybrid scheme based on the pseudo-spectral method (PSM) and finite difference method (FDM). We based on the same focal depth, and 2 different thick deposition layers are used as models to analyze the relationship between site situation and the peak displacement of strong ground motion. The results show that the hybrid PSM/FDM method for seismic wavefield simulation combines with advantages of the pseudospectral method and the finite difference method and makes up for the disadvantage of the pseudospectral method and the finite difference method, so this method can process well the calculation of the discontinuous medium surface, then the calculation accuracy is similar to the pseudospectral method. Through the wavefield simulation it is known that the range of the seismic wavefield the peak ground displacement (PGD) of the thicker deposition is larger and the influence of the secondary surface wave at the basin edge is more obvious. The thicker deposition amplitude of strong ground motion in the basin is larger and the duration is longer, and the reflected wave of which is more obvious and stronger. However, the difference of the site condition has little influence to strong ground motion in the horizontal direction.

Effects of Viscosity and Free-Surface Nonlinearity on the Wave Motion Generated by an Oscillating Twin Hull

2012 ◽  
Author(s):  
Palaniswamy Ananthakrishnan
Keyword(s):  
Free Surface ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Potential Flow ◽  
Wave Motion ◽  
Stokes Equations ◽  
Curvilinear Coordinates ◽  
Linear Potential ◽  
Nonlinear Free Surface

The hydrodynamics of a rectangular, floating twin hull under heave oscillation is analyzed to determine viscous and nonlinear effects on the radiation hydrodynamics of multi-hulls, in particular, at the resonant frequency corresponding to the piston (Helmholtz) mode of wave motions. A second-order finite-difference method based on boundary-fitted coordinates is used for the solution of the incompressible Navier-Stokes equations together with exact nonlinear viscous boundary conditions. To separate the viscosity effects from the nonlinear free-surface effects, through comparison of results, nonlinear inviscid results are also obtained using a boundary-fitted curvilinear coordinates based finite difference method. The nonlinear inviscid algorithm is based on the Eulerian-Lagrangian formulation of the nonlinear free-surface flow. The nonlinear results are compared with the linear potential-flow results obtained by Yeung and Seah [20] to quantify the combined nonlinear and viscous effects on the wave forces. The present results show the overall behavior of the wave motion to be similar to that predicted by the linear potential-flow theory [20]. Our results show that the effects of nonlinearity and viscosity on the wave motion can be significant for the Helmholtz mode, particularly for small separation distance between the hulls, which result in large vertical oscillation of the mean surface between the hulls. For small amplitudes of oscillation, the hydrodynamic pressure forces computed in the present analysis are in striking agreement with that given by the linear potential-flow analysis of Yeung and Seah [20].

A High-Order Finite-Difference Method on Staggered Curvilinear Grids for Seismic Wave Propagation Applications with Topography

2021 ◽  
Author(s):  
Ossian O’Reilly ◽  
Te-Yang Yeh ◽  
Kim B. Olsen ◽  
Zhifeng Hu ◽  
Alex Breuer ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Vertical Axis ◽  
Cartesian Grid ◽  
Staggered Grid ◽  
Graphic Processing Units ◽  
Curvilinear Grids ◽  
Curvilinear Grid

ABSTRACT We developed a 3D elastic wave propagation solver that supports topography using staggered curvilinear grids. Our method achieves comparable accuracy to the classical fourth-order staggered grid velocity–stress finite-difference method on a Cartesian grid. We show that the method is provably stable using summation-by-parts operators and weakly imposed boundary conditions via penalty terms. The maximum stable timestep obeys a relationship that depends on the topography-induced grid stretching along the vertical axis. The solutions from the approach are in excellent agreement with verified results for a Gaussian-shaped hill and for a complex topographic model. Compared with a Cartesian grid, the curvilinear grid adds negligible memory requirements, but requires longer simulation times due to smaller timesteps for complex topography. The code shows 94% weak scaling efficiency up to 1014 graphic processing units.

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