Geometric effects on convective coupling and interfacial structures in bilayer convection

The effects of boundaries on bilayer convection in a cylinder with idealized boundary conditions are studied. Using as examples two bilayer systems, a plot of the Rayleigh number versus aspect ratio (radius-height) is calculated. For certain systems, the type of convection coupling, either thermal or viscous, will change as the width of the container changes, even as the height is fixed. Additionally, the interfacial structure is calculated to help identify the driving force for the convection. Sudden changes in the convection coupling and the dominant driving force of convection are found as the container radius increased. The oscillatory onset of convection and the possibility of oscillating nonlinear dynamics are also identified.