三维磁场有限元—无限元耦合数值模拟  

3D magnetic field forward modeling by finite-infinite element coupling method

作　　者：郭楚枫 张世晖[1] 刘天佑[1] GUO Chu-Feng;ZHANG Shi-Hui;LIU Tian-You(Institute of Geophysics and Geomatics,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)地球物理与空间信息学院,湖北武汉430074

出　　处：《物探与化探》2021年第3期726-736,共11页Geophysical and Geochemical Exploration

基　　金：雄安新区深层地热资源探测评价技术示范项目(2018YFC0604303);深部资源预测系统技术研究与示范项目(2017YFC0601504)。

摘　　要：利用传统有限单元法在有限空间范围内开展三维地球物理场正演模拟时,由于截断边界的影响,会引起局部异常的畸变,影响数值模拟的精度,对该问题通常采用扩边的办法加以解决,但需要的范围较大,从而大大增加运算成本,影响正演模拟效率。本文基于COMSOL Multiphysics软件,在求解域外部边界设置无限元以替代传统边界条件,达到减小计算区域目的。通过孤立球体和组合模型磁场正演模拟,考虑退磁、剩磁及地表起伏条件,与传统有限元方法相比,有限元—无限元耦合算法能够有效克服边界效应,提高计算精度,降低运算量,从而提高了有限单元法正演数值模拟效率。Due to the influence of the artificial boundary condition, when the conventional finite element method is used to carry out the forward simulation of the three-dimensional geophysical field in a limited space, local abnormal distortion may occur, which affects the accuracy of the numerical simulation. This problem is usually solved by expanding the edge, but this requires a larger range, which greatly increases the computational cost and affects the efficiency of forward simulation. In this paper, on the basis of COMSOL Multiphysics software, infinite elements are set on the external boundary to replace the traditional boundary conditions so as to reduce the calculation area. Compared with the traditional finite element method, the finite element infinite element coupling method, by setting the isolated sphere and the combined body model and considering the conditions of demagnetization, remanence and surface undulation, can effectively overcome the boundary effect, improve the calculation accuracy and reduce the amount of calculation, thus improving the forward numerical simulation efficiency of the finite element method.

关 键 词：有限元—无限元 三维正演 磁法勘探 COMSOL 

分 类 号：P631[天文地球—地质矿产勘探]