Vertically staggered patterns in free convective flow

The paper reports experiments in which the basic mode is suppressed and higher-order modes can be realized. Vertical staggered cellular modes are generated by inhibiting the growth rate of the convection. This is achieved by enhancement of friction forces through a decrease in the separation of the lateral rigid boundaries of the container (slot). The cases of quasi-steady heating and transient heating are considered. It is shown that in a container (slot) of large height-to-width ratio (L/D), layered cellular convection may occur at large enough temperature differences between top and bottom, the cell pattern being dependent on the magnitude of the temperature difference and the L/D aspect ratio. With increasing temperature differences or decreasing aspect ratios the formation of two convective double rolls, one on top of the other, is predominant. Features of this phenomenon are discussed.