ADAPTIVE MODIFIED METHOD OF CHARACTERISTICS TO SOLVE THE ONE-DIMENSIONAL SOLUTE TRANSPORT-EQUATION

Simulation of advection-dominated solute transport in a porous medium is complicated due to the inherent problems of numerical dispersion an d oscillation. We propose an adaptive modified method of characteristi cs (AMMOC) to simulate one-dimensional, advection-dominated solute tra nsport problems, which incorporates the advantage of a self-adaptive s patial grid system with the computational power of the modified method of characteristics (MMOC) to deal with numerical dispersion and oscil lation. The numerical simulations, including a pure advection problem, show that the AMMOC is free of oscillation, approximately global mass conservative, and exhibits insignificant numerical dispersion. Relate d to this method, three interpolation schemes to obtain the concentrat ion of the fictitious particle at the previous time step were also eva luated. Our simulations show that the AMMOC, based on a clipped quadra tic interpolation scheme, provides the most accurate results.