High-accuracy gravity field and gravity gradient forward modelling based on 3D vertex-centered finite-element algorithm
Gravity anomalies generated by density non-uniformity are governed by the 3D Poisson equation.Most existing forward methods for such anomalies rely on integral techniques and cell-centered numerical approaches.Once the gravitational potential is calculated,these numerical schemes will inevitably lose high accuracy.To alleviate this problem,an accurate and efficient high-order vertex-centered finite-element scheme for simulating 3D gravity anomalies is presented.Firstly,the forward algorithm is formulated through the vertex-centered finite element with hexahedral meshes.The biconjugate gradient stabilized algorithm can solve the linear equation system combined with an incomplete LU factorization(ILU-BICSSTAB).Secondly,a high-degree Lagrange interpolating scheme is applied to achieve the first-derivate and second-derivate gravitational potential.Finally,a 3D cubic density model is used to test the accuracy of the vertex-centered finite-element algorithm,and thin vertical rectangular prisms and real example for flexibility.All numerical results indicate that our high-order vertex-centered finite-element method can provide an accurate approximation for the gravity field vector and the gravity gradient tensor.Meanwhile,compared to the cell-centered numerical algorithm,the high-order vertex-centered finite element scheme exhibits higher efficiency and accuracy in simulating 3D gravity anomalies.
NETL
NSTL
万方数据
