Numerical simulation of evaporation driven turbulent convection with a descending free surface *

In this paper, we report on direct numerical simulations (DNS) of turbulent thermal convection of water driven by free surface evaporation above and by a heated wall below. The geometry considered herein is a cube and the Rayleigh number in our simulations is Ra = 1.3 × 10⁸. The evaporation rates are estimated via a dynamic model based on the presumed ambient conditions above the liquid water. The evaporative and convective heat losses predicted by this model are then used to prescribe an inhomogeneous, non-zero temperature gradient at the free surface. In our study we consider high evaporation rates for which the loss of liquid water is no longer negligible. For this reason, we take into account the loss of water and the descent of the free surface by a remeshing procedure.

In the first part of this talk, we outline the evaporation model mentioned above and the remeshing procedure that we follow. Next, we analyze the properties and structure of the Large Scale Circulation that is developed in the flow. Our talk concludes with the presentation of turbulence statistics for the flow in hand.