每年出版 6 期
ISSN 打印: 1940-2503
ISSN 在线: 1940-2554
Indexed in
ON ULTIMATE REGIME OF RAYLEIGH-BENARD CONVECTION
摘要
Turbulent convection of liquid in a vertical narrow channel is simulated numerically for the case of heating from below. The liquid is assumed to be viscous and incompressible, the horizontal boundaries flat, isothermal, and free from shear stress, and the vertical boundaries adiabatic rather than isothermal. The Boussinesq approach without any semiempirical relationships (DNS) has been used, and the flow is considered to be two-dimensional and nonstationary. A special pseudo-spectral method with enough resolution and Prandtl number equal to 10 is used to investigate the asymptotic regime of convection at high Rayleigh number (ultimate regime). By means of a direct numerical simulation of convection in a two-dimensional narrow channel, with the channel height divided by its width, being of order 10, this regime may be derived with a relatively low Rayleigh number value of order 2×109. Nusselt and Reynolds numbers in the new asymptotic regime derived are linear functions of Rayleigh number, Nu~Ra and Re~Ra. The linear law derived for Nusselt and Reynolds numbers appears to be additional to the conventional root law.