OSCILLATORY MOTION IN A SIDE-HEATED CAVITY

Direct numerical simulations of the transient flow in a side-heated cavity have been conducted for a Rayleigh Number of 2 x 109, an aspect ratio of 1 and a Prandtl Number of 7.1. The results show the presence of both long-period and short-period oscillations. The long-period oscillation is a cavity-scale mode produced by the tilting of the isotherms. The short-period oscillations are shown to be the result of two distinct boundary-layer instabilities. Whereas the latter oscillations can produce large deviations in the observed temperature records, they are relatively shortlived and have only a minor influence on the evolution of the flow towards steady state. The suggestion of the existence of an internal hydraulic jump in such flows has been investigated and found to be incorrect. © 1990, Cambridge University Press. All rights reserved.