DISCRETE DISPERSION-RELATIONS AND TAYLOR-GALERKIN FEM FOR TRANSPORT OF DISPERSED FRONTS

A time and space accurate method for computing the movement of an adso rbing contaminant in a carrier fluid is presented. The method uses a f inite element analog to a previously described finite difference appro ach which can accurately describe movement of highly convected, but di spersing fronts. An operator splitting scheme between convection and d ispersion is employed which provides fourth order time accuracy on the convection step. The higher accuracy for the convection step is also accompanied with better mass conservation properties than is common fo r most algorithms which model purely convective problems. The method i s demonstrated on problems varying in one dimension by applications to pure convection-dispersion, the nonlinear Burger's equation, convecti on-reaction equations, and convection-dispersion through an adsorbing medium. The model predictions are found to provide accurate and stable results.