Hybrid Laplace transform finite element method for solving the convection–dispersion problem

✍ Scribed by Li Ren; Renduo Zhang

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 232 KB
• Volume: 23
• Category: Article
• ISSN: 0309-1708
• DOI: 10.1016/s0309-1708(99)00013-5

✦ Synopsis

It can be very time consuming to use the conventional numerical methods, such as the ®nite element method, to solve convection± dispersion equations, especially for solutions of large-scale, long-term solute transport in porous media. In addition, the conventional methods are subject to arti®cial diusion and oscillation when used to solve convection-dominant solute transport problems. In this paper, a hybrid method of Laplace transform and ®nite element method is developed to solve one-and two-dimensional convection±dispersion equations. The method is semi-analytical in time through Laplace transform. Then the transformed partial dierential equations are solved numerically in the Laplace domain using the ®nite element method. Finally the nodal concentration values are obtained through a numerical inversion of the ®nite element solution, using a highly accurate inversion algorithm. The proposed method eliminates time steps in the computation and allows using relatively large grid sizes, which increases computation eciency dramatically. Numerical results of several examples show that the hybrid method is of high eciency and accuracy, and capable of eliminating numerical diusion and oscillation eectively.