TURBULENT TRAVELING-WAVE CONVECTION IN A 2-LAYER SYSTEM

When layers of salt and sugar solution are separated by a ''diffusive' ' interface, interfacial waves are spontaneously generated by the turb ulent convection once the system evolves to a critical value of the de nsity-anomaly ratio R rho = beta Delta S/alpha Delta T (Stamp ct al., to appear in J. Fluid Mech). The waves modulate the interfacial fluxes by modifying the interface thickness and thereby organize the otherwi se random convective motions into coherent large-scale circulations. I n narrow rectangular channels a wide range of conditions give rise to a single wave which propagates back-and-forth, resulting in quasi-peri odic reversals of tank-scale circulations. Here it is shown that in an nular and equant rectangular cavities this same coupling phenomenon pr oduces turbulent convection cells of a traveling-wave nature, coupled to large-amplitude solitary waves on the interface. (C) 1997 American Institute of Physics.