Weakly Nonlinear Traveling-Wave Convection in an Annulus

In a weakly nonlinear traveling-wave convection in binary fluids in a rectangular container, reflection of the waves from the endwalls necessarily produces oppositely-propagating wave components. The nonlinear interactions between these waves lead to complex spatiotemporal states. In an annular geometry, such reflections are absent, and it is expected that the dynamics of the convection should be much different. Here, we report experiments on linear and weakly nonlinear traveling-wave convection in an annular container. A unidrectional Traveling-wave state exhibiting complicated dynamics is observed.