DRM-MD approach for the numerical solution of gas flow in porous media, with application to landfill

In the present work two different Dual Reciprocity Method (DRM) formulations were developed, for convection-diffusion flow of a mixture of gases in a multi-layer porous media, with an application to landfills. The first method treated the whole problem domain as a single one, while the second formulation, the Dual Reciprocity Method Multi-Domain decomposition (DRM-MD), divides the initial domain into a large number of subdomains. The main advantage of the single domain formulation, in relation to domain methods, is that only surface elements are necessary, so the input data is reduced. A drawback of this approach is that it results in a fully populated matrix system, limiting it to small or medium size problems. On the other hand, the DRM-MD formulation extends the range of applications of the technique to large problems, since the final matrix of the system is sparse (band diagonal) and the matrix coefficients of geometrically similar subregions are calculated only once. (C) 1998 Elsevier Science Ltd. All rights reserved.