The flow at the end of a shallow laterally healed cavity.

Shallow cavity flows, driven by horizontal thermal gradients, are analyzed over a range of Rayleigh numbers R and Prandtl numbers sigma. Particular emphasis is placed on the limit in which R is comparable with the cavity aspect ratio L. Departures from two-dimensional steady Hadley cells, defined by the limit L -> infinity at fixed R and sigma, are shown to be associated with non-linear end effects. Eigenvalue calculations indicate the existence of a critical Prandtl number sigma(omicron) below which the main core structure is not necessarily parallel with the horizontal boundaries. For sigma sigma(omicron) the parallel flow core is destroyed at Rayleigh numbers R > R(c) (sigma). Results for the stability boundary R(c)(sigma) are presented.