摘要
利用基于六面体的矢量有限元法进行大地电磁正演模拟时,在电性变化剧烈的区域有可能因为网格剖分的不够细致,导致六面体单元中的场值无法通过十二条棱边的插值准确表达,从而形成误差.另外,由于有限元剖分网格不可能无限延伸,而大地电磁场的边界条件在无穷远处才能得到满足;所以不恰当的网格剖分策略可能造成数值模拟计算结果误差过大.本文研究了不同频率下误差产生的规律及原因,并提出了减小误差的方法.最后根据误差分析对正演过程进行了优化,即保证了计算精度又大大提高了正演速度.
When using hexahedral edge-based finite element method to conduct a three-dimensional magnetotelluric forward experiment, it is possible that in regions of severe electrical changes, unreasonable partition of mesh may lead to the result that the values of hexahedral elements cannot be expressed correctly by interpolation functions of their twelve edges, thus causing errors. Moreover, the width-limited mesh does not satisfy magnetotelluric boundary conditions that are correct at infinity. Therefore, inappropriate mesh generation strategy may cause serious errors in numerical simulation results. In this paper, reasons and rules of errors under different frequencies are analyzed, and the improving method is advanced. Finally, basing on error analysis, we optimized the process of forward, which not only ensured the computational precision but improved efficiency.
出处
《地球物理学进展》
CSCD
北大核心
2017年第2期516-521,共6页
Progress in Geophysics
关键词
大地电磁
三维正演模拟
矢量有限元
误差分析
正演优化
magnetotellurics
three-dimensional forward modelling
edge-based finite element method
error analysis
improving forward method
