摘要：In this paper, we present numerical simulations of saline, discontinuous density currents, in two and three dimensions. The simulation of these flows poses a severe challenge for all codes. In fact, the currents present characteristic flow instabilities at the interface which are constituted by small spatial scales. A very fine resolution of these scales is needed to adequately capture the instabilities. The two-dimensional simulations reported herein were performed with two CFD codes. The first one is a comprehensive finite-element platform, whereas the other one is a commercial code. The runs were undertaken under quite similar conditions. Simulations show that only when the mesh employed in the commercial code is strongly refined a convergent solution is attained, which is similar to the solution obtained with the finite-element CFD code. This result would warn about the indiscriminate use of commercial codes with supposedly “fine” meshes when simulating complex underflows. The solution with the finite-element code, in turn, shows the shedding of large vortices containing salt. These vortices do not have a physical basis, but they correspond to the true solution of the twodimensional Navier-Stokes Equations.
