2-D Finite Element Method For Magnetotelluric Forward Modeling Based On OpenMP

Magnetotelluric is a frequency domain electromagnetic sounding method,which be used to study electric property difference of geological body by the natural alternating field source?With the sustainable development of MT method,two-dimensional(2-D)and three dimensional(3-D)forward inversion method has continuous updating Morover,For the requirement of increasing the earth electromagnetic calculation accuracy and efficiency.At present,There are a lot of research aiming at precision of interpolation function in the finite element method(FEM)and solving linear equations.However some errors existarea subdivision in FEM.At the same time,towards the large sparse matrixlinear equations in MT forward problems,So parallel computationis a wonderful choice.This paper firstly made a summarize magnetotelluric numerical simulation and OpenMP parallel computing research history and research status at home and abroad.This article puts forward finite element method for two-dimensional MT forward numerical simulation.Start from Maxwell equations,the dissertation is derived from differential equation met by boundary conditions and variational problem of 2-D MT and is used to adopting by rectangular subdivision in the research area and bilinear interpolation algorithmin the computational process the next.The varied bandwidth storageis used to solve storage problems on the large sparse matrix and simultaneous equations.In this way,it can write programs by defining the apparent resistivity on TE and TM mode.On this basis,first studies the theory of parallel computing and manner,starting from the OpenMP parallel computing,realize 2-D MT forward parallelization for random frequency point based on OpenMP by related theory and exactly the same parallelization in the different frequency point.Through the above algorithm,improve computational efficiency.To prove this algorithm correctness,make a comparison betwee nactual result and theoretical values by designing a one-dimensional homogeneous model.Then to verify the accuracy and reliability of the program,make ananomalous two-dimensional model in homogeneous half-space and analyze abnormal effect by low resistivity.By summarizing the change rule of detectivity of anomalous body and using different grid subdivision method in different area,In order to summarize the grid subdivision for the influence of abnormal body buried depth.Analyze the application example of coal mining goaf land to verify the accuracy of actual simulation result and provide better application value gor coal detecting.