Modeling of groundwater flow and transport by the element -free Galerkin (EFG) method
Abstract
The purpose of this research was to determine if the element-free Galerkin (EFG) method could be utilized to model groundwater flows and solute transport. This method has been developed in mechanical engineering to simulate growing cracks or large deformation. Chapter 1 introduces the EFG method as an alternative to popular numerical methods, the finite element method and finite difference method. Chapter 2 describes how to apply the element-free Galerkin method to the partial differential equations and how to deal with boundary conditions using the EFG-FEM coupling technique. An element-free Galerkin computer code EFGGW was developed and verified by comparing numerical results to analytical solutions for well flow problems in a confined aquifer. Example simulations were made to demonstrate capability of the code solving flow problems in heterogeneous and fractured aquifers. Chapter 3 shows how to apply the method to the solution of the groundwater flow problems in unconfined aquifers whose boundaries are moving with time. The developed code EFGGW was extended in such a way that it can deal with the time-dependent boundary conditions. The code was used to simulate steady state and transient groundwater flow in unconfined aquifers, free-surface seepage flow in a dam. Difficulties associated with the free and moving boundary were successfully overcome by employing the EFG method. This method is different from the conventional finite element method (FEM), because it doesn't requires any element which takes extremely long time in the case of irregular boundaries. The main advantages of the method are the convenience of node generation and the simplified implementation of boundary conditions. The most attractive feature of the method is the capability to construct a generalized computer code that can be consistently applied to problem domains of any shape. To the author's knowledge, this is the first application of the EFG method with the EFG-FEM coupling technique to simulation of groundwater flow.
Degree
Ph.D.
Advisors
Leap, Purdue University.
Subject Area
Hydrology|Geology|Environmental science
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.