TRANSPORT IN A 2-D SATURATED POROUS-MEDIUM - A NEW METHOD FOR PARTICLE TRACKING

A new method for solving the transport equation based on the managemen t of a large number of particles in a discretized 2-D domain is presen ted. The method uses numerical variables to represent the number of pa rticles in a given mesh and is more complex than the 1-D problem. The first parr of the paper focuses on the specific management of particle s in a 2-D problem. The method also would be valid for three dimension s as long as the medium can be modeled similar to a layered system. As the particles are no longer tracked individually, the algorithm is fa st and does not depend on the number of particles present. The numeric al rests show that the method is nearly numerical dispersion free and permits accurate calculations even for simulations of low-concentratio n transport. Because each mesh is considered as a closed system betwee n two successive time steps, it is easy to add adsorption phenomenon w ithout any problem of numerical stability. The model is rested under c onditions that are extremely demanding for its operating mode and give s a good fit to analytical solutions. The conditions in which it can b e used to best advantage are discussed.