Boundary Element-free Analysis Of Unstable Well Flow In Groundwater

Boundary element-free method(BEFM)is a new element-free method(EFM).It is also a new numerical simulation method in recent years.This method combines The boundary integral equation with The improved moving least square method(IMLSM).The method is simple to simulate,only provides calculation boundary information,material information,ect,and does not need for element within an area or on a boundary.It also reduces the error and avoids many of the difficulties associated with the division of meshes or elements in the course of numerical simulation,such as Finite difference method(FDM),Finite element method(FEM),Boundary element method(BEM)and so on.In this dissertation,we expound the main principles and methods of BEFM.We propose to apply this method to the numerical simulation in the problems of unstable well flow in groundwater.The result of the test is acceptable.This paper consists of four parts.In the first part,respectively,we summarize the historical background of numerical simulation of groundwater,the history and current situation of EFM and BEFM,the significance of numerical simulation method for groundwater,also include my main work.In the second part,includes the preliminary knowledge.In this section,we introduce the main theory of Least squares method(LSM),IMLSM and Boundary integral equation method(BIEM).The third part summarizes the basic principle of BEFM.In the fourth part,BEFM is applied to solve the problems of unstable well flow in groundwater.The problems of unstable well flow in confined aquifer and unstable well flow in overflowing aquifer are studied by using this method,and the corresponding numerical models are established.The numerical simulation results of BEFM and BEM are compared with the exact solution of the example.It is concluded that the accurate of BEFM can reach the standard of BEM.Finally,the research and application of BEFM are summarized and prospected.As a new numerical simulation method,BEFM has its own unique advantages compared with the conventional numerical simulation methods of groundwater,and these advantages make BEFM some unique significance in the study of groundwater movement.It is believed that in the near future,BEFM will receive more extensive attention,application and development in such fields as hydrogeology and so on.