Influence of Bénard convection on solid–liquid interfaces

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Abstract
A laterally confined horizontal liquid layer is heated from below and cooled from above so that the single-component liquid is frozen in the upper part of the layer. When the imposed temperature difference is such that the Rayleigh number across the liquid is supercritical, there is Bénard convection in the liquid layer coupled with the dynamics of the solidification interface. Experimental results are presented for quasi-steady temperature variations at the horizontal boundaries. When the solidified layer is thick compared with the liquid layer a hysteresis loop is found for the heights of the liquid layer in a range of subcritical Rayleigh numbers. The interfacial corrugations exhibit a polygonal structure in this case. At Rayleigh numbers far above the critical value ‘bimodal patterns’ are observed with two distinct lengthscales. Finally a stability chart is given for the various interfacial patterns observed.