An Efficient Meshfree Point Collocation Moving Least Squares Method to Solve the Interface Problems with Nonhomogeneous Jump Conditions

摘要

We are going to study a simple and effective method for the numerical solution of the closed interface boundary value problem with both discontinuities in the solution and its derivatives. It uses a strong-form meshfree method based on the moving least squares (MLS) approximation. In this method, for the solution of elliptic equation, the second-order derivatives of the shape functions are needed in constructing the global stiffness matrix. It is well-known that the calculation of full derivatives of the MLS approximation, especially in high dimensions, is quite costly. In the current work, we apply the diffuse derivatives using an efficient technique. In this technique, we calculate the higher-order derivatives using the approximation of lower-order derivatives, instead of calculating directly derivatives. This technique can improve the accuracy of meshfree point collocation method for interface problems with nonhomogeneous jump conditions and can efficiently estimate diffuse derivatives of second- and higher-orders using only linear basis functions. To introduce the appropriate discontinuous shape functions in the vicinity of interface, we choose the visibility criterion method that modifies the support of weight function in MLS approximation and leads to an efficient computational procedure for the solution of closed interface problems. The proposed method is applied for elliptic and biharmonic interface problems. For the biharmonic equation, we use a mixed scheme, which replaces this equation by a coupled elliptic system. Also the application of the present method to elasticity equation with discontinuities in the coefficients across a closed interface has been provided. Representative numerical examples demonstrate the accuracy and robustness of the proposed methodology for the closed interface problems. (c) 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 1031-1053, 2015