Natural convection in vertical slots with wall temperature oscillation

Natural convection in vertical slots has been studied experimentally with oscillation of a cold wall temperature. It is found that at sufficiently large Rayleigh numbers travelling-wave instability occurs, but only in the region close to the cold wall when the hot wall is maintained at the initial temperature, and appears in both cold and hot regions when both hot and cold wall temperatures are changed simultaneously and symmetrically with the initial temperature value, although the hot wall temperature is kept constant after the change. The observed instability may be attributed to the leading-edge effect induced by the cold wall temperature oscillation, and selectively amplified by the natural convection flow.The author would like to thank Professor R. S. Tankin for his encouragement and assistance throughout this study. The financial support of the Natural Sciences and Engineering Research Council of Canada is gratefully acknowledged.