Convection of a Colloidal Suspension in a Horizontal Layer Heated from Below with Account for Nanoparticle Interaction

We investigate linear instability and 2D nonlinear convective flows of a colloidal suspension stratified in the gravity field in the case of a horizontal colloidal suspension layer with account for the particle interaction. The dependences of the oscillatory convection threshold, the neutral oscillation frequency, and the critical wavenumber on the average volume fraction of impurity are obtained. Nonlinear terms in the diffusion and sedimentation fluxes, which reflect the interaction of nanoparticles, reduce the average concentration gradient across the layer, as well as the convection threshold and the neutral oscillation frequency as compared to an ideal colloidal solution. We perform numerical simulation of a finite-amplitude flow in the form of a traveling wave. In contrast to molecular liquids and ideal colloidal solutions, the spatial structure of the concentration field is successfully described by the first harmonic and exhibits weak spatial anharmonism.