Dynamics of double convection

Abstract

Double-diffusive convection provides examples of the competition between stabilizing and destabilizing mechanisms in fluid mechanics, leading to a rich variety of complicated nonlinear behaviour. Weakly nonlinear convection can be described analytically and fully nonlinear solutions have been obtained in a series of numerical experiments on two-dimensional thermosolutal convection and magnetoconvection. These provide examples of various bifurcation structures including interactions between standing waves, travelling waves and steady solutions, transitions to temporal chaos, loss of spatial symmetry and the development of spatiotemporal chaos. The behaviour found in the numerical experiments can be related to low-order systems derived as normal form equations for the appropriate degenerate bifurcations.