A DIRECT NUMERICAL-SIMULATION APPROACH TO THE STUDY OF INTRUSION FRONTS

A direct numerical simulation approach for the study of gravity curren ts in a plane channel is described. The numerical method employed is b ased on a mixed spectral/spectral-element discretization in space toge ther with finite differences in time. For the validation of the code, simulations of Rayleigh-Benard convection are performed and the result s are compared with theoretical predictions and reference data from th e literature. The dynamics of gravity currents is then studied by simu lations of two-dimensional lock-exchange flow. The results obtained in these simulations are in good agreement with recent experimental data . By a systematic variation of the Grashof number the influence of vis cous diffusion on the characteristics of the propagating fronts is ass essed.