Boundary layers in rotating weakly turbulent Rayleigh-Benard convection

Abstract

The effect of rotation on the boundary layers (BLs) in a Rayleigh-Benard (RB) system at a relatively low Rayleigh number, i.e. $Ra=4\times 10^7$, is studied for different Pr by direct numerical simulations and the results are compared with laminar BL theory. In this regime we find a smooth onset of the heat transfer enhancement as function of increasing rotation rate. We study this regime in detail and introduce a model based on the Grossmann-Lohse theory to describe the heat transfer enhancement as function of the rotation rate for this relatively low Ra number regime and weak background rotation $Ro\gtrsim 1$. The smooth onset of heat transfer enhancement observed here is in contrast to the sharp onset observed at larger $Ra\gtrsim 10^8$ by Stevens {\it{et al.}} [Phys. Rev. Lett. {\bf{103}}, 024503, 2009], although only a small shift in the Ra-Ro-Pr phase space is involved.

17 pages, 13 figures

References in corpus (5)

• Boundary layer structure in turbulent thermal convection and its consequences for the required numerical resolution
• Radial boundary layer structure and Nusselt number in Rayleigh-Benard convection
• Measured Instantaneous Viscous Boundary Layer in Turbulent Rayleigh-Bénard Convection
• Heat transport in rotating convection without Ekman layers
• Optimal Prandtl number for heat transfer in rotating Rayleigh-Benard convection

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• Thermal boundary layer profiles in turbulent Rayleigh-Bénard convection in a cylindrical sample
• Effect of aspect-ratio on vortex distribution and heat transfer in rotating Rayleigh-Bénard convection
• Breakdown of the large-scale wind in Γ=1/2 rotating Rayleigh-Bénard flow
• What rotation rate maximizes heat transport in rotating Rayleigh-Bénard convection with Prandtl number larger than one?
• Sharp transitions in rotating turbulent convection: Lagrangian acceleration statistics reveal a second critical Rossby number
• Critical Prandtl number for Heat Transfer Enhancement in Rotating Convection
• Effect of weak rotation on large-scale circulation cessations in turbulent convection