Experimental studies on the onset of thermohaline convection

Abstract

Measurements of the heat flux and temperature gradient in a layer of saline solution stably stratified by Soret diffusion and heated from below exhibit the onset of convection by the growth of very small oscillations which eventually trigger finite amplitude convection. The critical Rayleigh numbers and periods of oscillation are consistent with published theoretical calculations. Several non-linear modes are observed, even for the same heat flux, near the point of onset.