%0 Journal Article
%A G Shiralkar
%A Ashok J Gadgil
%A Chang-Lin Tien
%B International Journal of Heat and Mass Transfer
%D 1981
%G eng
%N 10
%P 1621 - 1629
%R 10.1016/0017-9310(81)90070-3
%T High Rayleigh Number Convection in Shallow Enclosures with Different End Temperatures
%V 24
%8 10/1981
%! International Journal of Heat and Mass Transfer
%X <p>Buoyancy-driven laminar convection in shallow horizontal enclosures (width/height ⪢1) with adiabatic horizontal walls and isothermal vertical walls of different temperatures has been investigated for very high Rayleigh numbers (<em>Ra</em> ⪢ 10<sup>6</sup>). It is found that this flow regime, which is characterized by boundary layers lining both the vertical and horizontal walls, differs qualitatively from the low-<em>Ra</em> flow regime, in which the horizontal boundary layers are absent. The decreasing influence of <em>Ra</em> on the Nusselt number and the effect of the aspect ratio are analytically shown and then numerically verified. Comparison is made with existing experimental and numerical data, and a new correlation is proposed for the Nusselt number in this flow regime. An explanation is also advanced regarding the current controversy about the power dependence of the Nusselt number on <em>Ra</em> in narrow vertical channels.</p>