Homogeneous Rayleigh-Bénard convection
نویسندگان
چکیده
Much effort has been expended in recent decades in addressing the problem of heat transfer in Rayleigh-Bénard (RB) thermal convection cells. There is increasing agreement that in general there are no clean scaling laws for Nu(Ra, Pr) and Re(Ra, Pr), apart from asymptotic cases. One of these asymptotic cases has been doped the ultimate state of thermal convection, i.e. Ra → ∞, where the heat flux becomes independent of the kinematic viscosity ν and the thermal diffusivity κ. The physics of this regime is that the thermal and kinetic boundary layers have broken down or do not play a role any more for the heat flux and the flow is bulk dominated. Scaling laws for this regime were first suggested by Kraichnan [1], and later by Spiegel [2]. The recent Grossmann-Lohse (GL) theory [3] also gives such an asymptotic regime which is bulk dominated and where the plumes do not play a role , namely Nu ∼ RaPr, (1)
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