Interfacial Effects on the Onset of Convection in Horizontal Liquid Layers
Horizontal liquid layers are prone to convective instability when subjected to appropriate vertical gradients of temperature and/ or concentration. Whenever fluid-fluid interfaces are present the two potentially destabilizing mechanisms inducing convective instability in the configuration are buoyancy and surface tension. The onset of convection in the configuration depends also on the boundary conditions imposed, i.e., on the physical properties of the adjoining media, more so, if one of the driving mechanisms is itself of interfacial origin. The two destabilizing mechanisms in the configuration in general reinforce each other, i.e., the adverse (temperature/concentration) gradient necessary to induce instability when both the mechanisms are present is smaller than that required when only one of them is involved. This well known result due to Nield1, however, turns out to be critically dependent on the detailed characterization of the two-fluid interface and the associated boundary conditions.
KeywordsSolidification Front Convective Instability Critical Wave Number Neutral Stability Curve Neutral Curf
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