NUMERICAL SIMULATION OF BE´NARD-MARANGONI CONVECTION IN SMALL ASPECT RATIO CONTAINERS

Abstract

This study investigates, by means of numerical simulation, coupled gravity and capillarity-driven thermoconvection of a fluid layer heated from below (Be´nard-Marangoni convection), close to the threshold and in small aspect ratio containers. First, we present a broad validation of the numerical model we have developed onto widely recognized results available from experimental, theoretical, and numerical fields. Furthermore, we report the numerical results we have obtained in analyzing the dependence on the convective cell pattern of the container shape. In the smallest aspect ratio range only a few cells can develop, so the convective patterns mainly depend on the aspect ratio and the shape of the container, but no major transient evolution can be observed. On the other hand, larger aspect ratio containers allow a comparatively large number of cells to develop. The shape of the container plays a significant part in the transient stage until the stationary pattern is attained, in which hexagonal cells prevail at the core surrounded by a row of predominantly pentagonal cells.