A Hamiltonian Particle Method with a Staggered Particle Technique for Simulating Seismic Wave Propagation
A Hamiltonian Particle Method with a Staggered Particle Technique for Simulating Seismic Wave Propagation
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DOI：
10.1007/s00024-013-0763-x
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发表时间：
2014-01
影响因子：
2
通讯作者：
J. Takekawa;H. Mikada;T. Goto
中科院分区：
文献类型：
--
作者：
J. Takekawa;H. Mikada;T. Goto
本文提出了一种用交错粒子技术模拟地震波传播的哈密顿粒子方法。在传统的HPM中，物理变量，例如颗粒位移和应力，被定义在中心，即，在同一个位置，每个粒子。由于大多数使用有限差分法（FDM）进行的地震模拟都采用交错网格技术，我们知道空间变量的交错排列可以提高数值精度。在本研究中，我们假设交错技术也可以提高HPM的数值精度，并验证了这一假设。首先，为了验证我们的策略的有效性，我们进行了一个平面波分析的HPM与交错粒子。通过与传统方法的网格离散度比较，表明采用交错网格技术可以显著提高计算精度。还观察到，由于相同参数下相邻两个粒子的平均间距不同，波的色散取决于传播方向，正如在旋转交错网格的FDM中通常观察到的那样。接下来，我们比较了从传统的兰姆问题，使用我们的HPM与那些从分析方法，以证明交错粒子技术的有效性的结果。我们的结果表明，更好的协议与解析解比那些从HPM没有交错粒子。我们认为，在地震波传播模拟中，交错质点技术是一种提高计算精度的方法。
We present a Hamiltonian particle method (HPM) with a staggered particle technique for simulating seismic wave propagation. In the conventional HPM, physical variables, such as particle displacement and stress, are defined at the center, i.e., at the same position, of each particle. As most seismic simulations using finite difference methods (FDM) are practiced with staggered grid techniques, we know the staggered alignment of space variables could improve the numerical accuracy. In the present study, we hypothesized that staggered technique could improve the numerical accuracy also in the HPM and tested the hypothesis. First, we conducted a plane wave analysis for the HPM with the staggered particles in order to verify the validity of our strategy. The comparison of grid dispersion in our strategy with that in the conventional one suggests that the accuracy would be improved dramatically by use of the staggered technique. It is also observed that the dispersion of waves is dependent on the propagation direction due to the difference in the average spacing of the neighboring two particles for the same parameters, as is usually observed in FDM with a rotated staggered grid. Next, we compared the results from the conventional Lamb’s problem using our HPM with those from an analytical approach in order to demonstrate the effectiveness of the staggered particle technique. Our results showed better agreement with the analytical solutions than those from HPM without the staggered particles. We conclude that the staggered particle technique would be a method to improve the calculation accuracy in the simulation of seismic wave propagation.