Onset of convection in a rotating annulus with radial gravity and heating

The onset of convection in fluids confined in a vertical rotating cylindric al annulus with radial gravity and heated from the inside is analyzed. Solu tions to the eigenvalue problem are found numerically for Bat lids and eith er no-slip or stress-free boundary conditions on these surfaces. Except in special cases occurring with the latter boundary conditions all critical mo des precess in the rotating frame. The critical Rayleigh number and the cor responding precession frequency are computed for low-Prandtl number fluids and both types of boundary conditions as a function of the Taylor number, t he radius ratio and the aspect ratio, and the critical modes identified and compared. (C) 1999 The Japan Society of Fluid Mechanics and Elsevier Scien ce B.V. All rights reserved.