Logarithmic temperature profiles of turbulent Rayleigh–Bénard convection in the classical and ultimate state for a Prandtl number of 0.8

Logarithmic temperature profiles of turbulent Rayleigh–Bénard convection in the classical and ultimate state for a Prandtl number of 0.8

Guenter Ahlers1,2,†,‡, Eberhard Bodenschatz2,3,4,‡ and Xiaozhou He2,‡ 1Department of Physics, University of California, Santa Barbara, CA 93106, USA 2Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen, Germany 3Institute for Nonlinear Dynamics, University of Göttingen, 37077 Göttingen, Germany 4Laboratory of Atomic and Solid-State Physics, and Sibley School of Mech...

Logarithmic temperature profiles in the bulk of turbulent Rayleigh–Bénard convection for a Prandtl number of 12.3

We report measurements of logarithmic temperature profiles Θ(z, r)=A(r)× ln(z/L)+ B(r) in the bulk of turbulent Rayleigh–Bénard convection (here Θ is a scaled and timeaveraged local temperature in the fluid, z is the vertical and r the radial position, and L is the sample height). Two samples had aspect ratios Γ ≡D/L= 1.00 and 0.50 (where D = 190 mm is the diameter). The fluid was a fluorocarbo...

Logarithmic temperature profiles in turbulent Rayleigh-Bénard convection.

We report results for the temperature profiles of turbulent Rayleigh-Bénard convection (RBC) in the interior of a cylindrical sample of aspect ratio Γ≡D/L=0.50 (D and L are the diameter and height, respectively). Both in the classical and in the ultimate state of RBC we find that the temperature varies as A×ln(z/L)+B, where z is the distance from the bottom or top plate. In the classical state,...

Turbulent Rayleigh–Bénard convection for a Prandtl number of 0.67

For the Rayleigh-number range 10 Ra 10 we report measurements of the Nusselt number Nu and of properties of the large-scale circulation (LSC) for cylindrical samples of helium gas (Prandtl number Pr=0.674) that have aspect ratio Γ ≡D/L=0.50 (D and L are the diameter and the height respectively) and are heated from below. The results for Nu are consistent with recent direct numerical simulations...

Logarithmic Bounds for In nite Prandtl Number Rotating Convection