Numerical modeling of water flow below dry salt lakes: effect of capillarity and viscosity
1999
Boufadel, M.C. | Suidan, M.T. | Venosa, A.D.
We investigate numerically the effects of capillarity and viscosity on density-dependent flows below dry salt lakes. The numerical model, MARUN (Boufadel, M.C., Suidan, M.T., Venosa. A.D., 1999a. A numerical model for density-and-viscosity-dependent flows in two-dimensional variably-saturated media. J. Contam. Hydrol. 37, 1-20) is used to assess the combined and separate effects of capillarity and concentration-engendered viscosity on the groundwater dynamics of a two-dimensional system simulating a dry lake. We found that accounting for concentration-engendered viscosity effects under saturated water flow conditions gives totally different groundwater dynamics from the case where these effects are neglected. However, concentration-dependent viscosity effects were minor when unsaturated water flow conditions were present. Under variably saturated flow conditions, capillarity effects gave totally different hydraulics in the porous domain from the saturated flow case; upwelling regions observed under saturated flow conditions were downwelling when capillarity effects were present. A mesh orientation study revealed that density-dependent flows were susceptible to the orientation of the diagonals of the triangular elements. A discussion on the accuracy and the efficiency of the MARUN model in the context of density- and viscosity-dependent flows in two-dimensional variably-saturated media is also provided.
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