3-DIMENSIONAL CONVECTION DRIVEN BY CENTRIFUGAL BUOYANCY

Convection driven by centrifugal buoyancy in a cylindrical fluid annulus cooled from the inside, heated from the outside, and rotating about its axis is described. While at high values of the dimensionless rotation parameter tau convection rolls aligned with the axis are preferred, three-dimensional patterns of convection are introduced at low values of tau through either the cross-roll instability or a subharmonic varicose instability. The instabilities are studied in terms of simple analytical relationships as well as through numerical methods based on the Galerkin scheme. Analytical expressions for the steady three-dimensional patterns induced by the instabilities are also derived.