Low Rayleigh number convection in horizontal, eccentric annuli

Low Rayleigh number thermal convection in a Newtonian fluid confined between two horizontal, circular cylinders is studied analytically using a regular perturbation expansion. Both cylinders are impermeable and maintained at different, uniform temperatures. The line connecting the cylinders’ centers (referred to as the intracenter line) may be inclined at an arbitrary angle with respect to the gravity vector. When the intracenter line is parallel to the gravity vector, bicellular convection is observed in the annulus and the flow is symmetrical with respect to the intracenter line. When the intracenter line is inclined with respect to the gravity vector, the flow domain is doubly connected. The flow is asymmetrical vis‐a‐vis the intracenter line; and, in addition to the cellular convection, there is net circulation around the inner cylinder. This circulation consists of fluid ascending on one side of the inner cylinder and descending on the other.