Modeling strongly coupled groundwater flow and solute transport in porous medium: reevaluation of the salt dome flow problem

Case 5, Level 1 of the international HYDROCOIN groundwater flow modelling project, is an example of idealised flow over a salt dome. Several independent teams simulated this problem using different models. Results obtained by different codes can be contradictory. We develop a new numerical model, TVDV-2D based on the mixed hybrid finite elements approximation for flow, which provides a good approximation of the velocity, and the discontinuous finite elements approximation to solve advection equation, which gives a good approximation of concentration even when dispersion tensor is very small. We use the TVDV-2D code to simulate the salt dome flow problem. In this paper we study the effect of dispersion and we compare linear and non-linear dispersion equations. We show the importance of the discretization of the constant concentration boundary condition on the extent of recirculation and the final salt distribution. We study also the salt dome flow problem with a more realistic dispersion (very small dispersion tensor). Our results are different from prior works with regard to the magnitude of recirculation and the final concentration distribution. In all cases, our results show recirculation in the lower part of the domain. When the dispersion tensor becomes very small, the magnitude of recirculation is small.