Numerical characterization of hydrothermal waves in a laterally heated shallow layer

Instabilities of a buoyancy-thermocapillary flow in a three-dimensional differentially heated layer have been examined by means of direct numerical simulations, in order to have a more detailed description of the flow field with respect to that obtained experimentally. The main aim of this work is the numerical modelization of some experiments performed by Riley and Neitzel [J. Fluid Mech. 359, 143 (1998)], considering a cavity 30 mmx1 mmx50 mm filled with a silicone oil (Prandtl number equal to 13.9). Hydrothermal waves have been observed and examined in detail. Further simulations have been performed in order to describe also a basic unicellular flow and a steady multicellular flow. The numerical code is based on the vorticity-velocity formulation of the Navier-Stokes equations for an incompressible fluid, solved in time by means of a fully implicit approach. (C) 2004 American Institute of Physics.