Flow of Colloid Liquid in Horizontal Cell under Heating from Sidewall

Abstract

Based on numerical simulation, the influence of sedimentation on the convective flow of colloid liquids filling a horizontal cell heated from the sidewall is studied. The set of nonlinear equations is solved by the finite-difference method using explicit schemes. Three convective patterns differing in spatial structure and behavior in time are distinguished. The transition between the patterns is accompanied by a jump in the dimensionless heat flow. Bifurcation diagrams of the convection patterns (the dependences of the heat flow intensity on the Rayleigh number) are given. It is shown that the weak flow of a colloidal suspension exists at a low temperature gradient, the intensity of which is several orders of magnitude lower than the intensity of the flow of a homogeneous liquid under the same parameters. The concentration in the flow with a weak intensity is redistributed in such a way that the density gradient becomes almost vertical, and the heat flow across the layer is absent at the same time. The transition from a weak to a strong one-vortex flow filling the entire cell proceeds abruptly. It is found the threshold of the transition from a weak to intense flow depends on the Boltzmann number characterizing the degree of gravitational stratification. One more flow, namely, a three-vortex flow with an intermediate intensity is generated upon a decrease in the Rayleigh number. Stream-function and concentration fields are manifested for all the observed types of flows.