Three-Dimensional Transient Advective Diffusion by Boundary Element Method using Direct Time Integral of the Fundamental Solution

The advective diffusion analyses have been applied to many fields of science and engineering, such as dispersion for chemically reacting(first-order reaction) substance, thermal transport in fluid, analysis of electromagnetic field caused by a moving magnet. electron transport in semiconductors, underground migration of radioactive waste, and so on. The boundary element method (BEM) has been developed extensively for the last decade to solve these transient advective diffusion equation. The time integrations of the fundamental solution in the boundary integral equation, however, make the BEM application to advective diffusion problems difficult. Therefore, the time integration has been approximated in the past relevant publications. This paper describes the BEM in which the time integration is done analytically, and technique is demonstrated with several examples. Good results have been obtained in the example calculations, where comparisons are made with the results from other numerical codes.