Spiral thermocapillary flows in two-layer systems

Parallel thermocapillary flows in infinite layers can be calculated easily. However, in reality thermocapillary flows occur in channels or closed cavi ties, and they are three-dimensional. In the present paper, a two-layer flu id system filling a channel with a rectangular cross section is considered. A numerical investigation of three-dimensional spiral thermocapillary flow s generated by a temperature gradient imposed along the channel has been pe rformed. Both the case of a zero longitudinal pressure gradient (a through flow in the channel) and that of a zero longitudinal fluid flux (a flow in the closed cavity) are investigated, steady and oscillatory thermocapillary motions, and transitions between them are studied. (C) 1999 Editions scien tifiques et medicales Elsevier SAS.