Orthogonal curvilinear grid generation technique used for numeric simulation of geophysical fields in undulating surface condition
Sun Jian-guo1,2, Jiang Li-li1,2
1. College of Geoexploration Science and Technology,Jilin University,Changchun City,Jilin Province,130026,China;
2. Ministry of Land and Resource Open Lab of Applied Geophysical Integrative Interpretation Theory,Jilin University,Changchun City,Jilin Province,130026,China
Abstract：The difficulty faced in numeric simulation of geophysical fields under the undulating surface condition lies how to solve the boundary condition in free-boundary (earth-to-space interface). Although there have been many ways until now,for example,mapping method,interpolation method and non-orthogonal grid method etc,all of them have some problems. In view of abovementioned difficulties,the paper presented a new solving way. First,introducing the orthogonal body-fitted grid technique developing in computation of fluid mechanics,the conclusion that the orthogonal curvilinear grid is superior to non-orthogonal curvilinear grid was gained by analyzing the differential equation (boundary condition) that should be met by elastic wavefield and DC electrical field in earth-to-space interface; then,using grid generation method based on Poisson equation and adopting Hilgenstock method to control source term,the orthogonal body-fitted curvilinear grid was generated in combination with algebraic auxiliary method. The results showed that the grid generating method presented in the paper is suitable to solve the numeric simulation issue of geophysical fields in undulating surface condition.
