Soret effect on propagation of thermoconvective waves in a binary mixture

Effects of thermal diffusion (Soret effect) on the propagation of thermoconvective waves (TCW) in a layer of binary mixture are investigated. It is shown that undamped propagation of TCW is possible in a layer heated from below provided the Soret number is large and positive. A novel result of the analysis is that for a layer heated from below, TCW which are strongly damped in the absence of thermal diffusion may propagate almost undamped in the low frequency limit in the presence of thermal diffusion for some negative value of Soret number. It is further shown that for a layer heated from above such that the solute concentration increases vertically upward, weakly damped propagation of TCW in the low frequency limit is inhibited with increase in Soret number. Received on 14 July 1998