Heat transport in rotating convection

We derive upper bounds for the Nusselt number in infinite Prandtl number ro tating convection. The bounds decay algebraically with Taylor number to the conductive heat transport value; the decay rate depends on boundary condit ions. We show moreover that when the rotation is fast enough the purely con ductive solution is the globally and nonlinearly attractive fixed point; th e critical rotation rate also depends on boundary conditions. The influence of the boundary conditions is explained physically in terms of Ekman layer s. (C)1999 Elsevier Science B.V. All rights reserved.