三度体重力矢量的有限单元法正演计算  

Forward Calculation of Three Dimensional Gravity Vector Using Finite Element Method

作　　者：蒋甫玉[1] 谢磊磊[1] 常文凯[1] 黄岩[2] 张作宏[2] 

机构地区：[1]河海大学地球科学与工程学院,南京210098 [2]江苏省地质勘查技术院,南京210048

出　　处：《吉林大学学报（地球科学版）》2015年第4期1217-1226,共10页Journal of Jilin University：Earth Science Edition

基　　金：江苏省自然科学基金项目(BK20140844);江苏省地质矿产勘查局科研技改项目(2014-KY-15)

摘　　要：以重力位在场源内部满足泊松方程为依据,以重力矢量满足第三类边界条件为切入点,推导了与三度体重力矢量满足的边值问题相对应的变分问题,进而利用有限单元法实现了对变分问题的求解。立方体模型试验结果表明:文中提出的新的系数矩阵存储方式较之传统方式能够更有效地节约存储空间,且为利用预条件共轭梯度技术更加快速地求解线性方程组提供了保障;重力矢量的计算精度与边界长度及单元网格的边长息息相关,其计算效率则主要取决于所要计算的节点总数和大型稀疏线性方程组求解算法的优劣;一般情况下,当单元的边长小于场源体边长的1/10、边界长度大于场源体长度的7.5倍时,能够获得理想的结果。Variational problem of three dimensional gravity vector was deduced to meet the boundary value based on Poisson equation and the third boundary condition,and the solution of variational problem is further implemented by using the finite element method.The results of the cubic model test show that the proposed new coefficient matrix storage strategy is more effective to save storage space than a traditional approach;this,in turn,makes it possible to quickly solve liner equations by using the preconditioned conjugate gradient technology.The calculation precision of the gravity vector is closely related to the boundary length and unit grid;while the computational efficiency mainly depends on the total number of nodes and the algorithm used in solving a large sparse system of linear equation.In general,when the length of unit grid is less than 1/10 of the body length,and the boundary length is greater than 7.5times of the length of the source,a desired result can be achieved.

关 键 词：变分问题 重力矢量 有限单元法 数据存储 计算精度 三度体 

分 类 号：P631.1[天文地球—地质矿产勘探]