Numerical study on oscillatory convection of cold water in a tall vertical enclosure
International Journal of Numerical Methods for Heat & Fluid Flow
ISSN: 0961-5539
Article publication date: 1 June 1999
Abstract
The stability of two‐dimensional natural convection of water near its density maximum (cold water) inside a vertical rectangular enclosure with an aspect ratio of eight is investigated via a series of direct numerical simulations. The simulations aim to clarify, under the influence of density inversion, the physical nature of the instability mechanism responsible for the laminar buoyancy‐driven flow transition from a steady state to an oscillatory state in the enclosure filled with cold water. Two values of the density inversion parameter, m= 0.4 and 0.5, where the density inversion of cold water may exert strong influence on the flow, are considered in the present study. The results show that the transition from steady state to periodically oscillatory convection arises in the cold‐water‐filled enclosure through a Hopf bifurcation. The oscillatory convection in the water‐filled enclosure for both values of m is found to feature an oscillatory multicellular structure within the contra‐rotating bicellular flow regions. A traveling wave motion accordingly results along the maximum density contour, which demarcates the contra‐rotating bicellular flows in the enclosure. For both cases the nature of transition into unsteadiness is found to be buoyancy‐driven. The critical Rayleigh number for the bifurcation at m = 0.4 is found to be markedly higher than that at m = 0.5.
Keywords
Citation
Ho, C.J. and Tu, F.J. (1999), "Numerical study on oscillatory convection of cold water in a tall vertical enclosure", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 9 No. 4, pp. 487-508. https://doi.org/10.1108/09615539910266639
Publisher
:MCB UP Ltd
Copyright © 1999, MCB UP Limited