TY - JOUR
T1 - Thermal boundary layer profiles in turbulent Rayleigh-Bénard convection in a cylindrical sample
AU - Stevens, Richard J.A.M.
AU - Zhou, Quan
AU - Grossmann, Siegfried
AU - Verzicco, Roberto
AU - Xia, Ke Qing
AU - Lohse, Detlef
PY - 2012
Y1 - 2012
N2 - We numerically investigate the structures of the near-plate temperature profiles close to the bottom and top plates of turbulent Rayleigh-Bénard flow in a cylindrical sample at Rayleigh numbers Ra=108 to Ra=2×1012 and Prandtl numbers Pr=6.4 and Pr=0.7 with the dynamical frame method [ Zhou and Xia Phys. Rev. Lett. 104 104301 (2010)], thus extending previous results for quasi-two-dimensional systems to three-dimensional systems. The dynamical frame method shows that the measured temperature profiles in the spatially and temporally local frame are much closer to the temperature profile of a laminar, zero-pressure gradient boundary layer (BL) according to Pohlhausen than in the fixed reference frame. The deviation between the measured profiles in the dynamical reference frame and the laminar profiles increases with decreasing Pr, where the thermal BL is more exposed to the bulk fluctuations due to the thinner kinetic BL, and increasing Ra, where more plumes are passing the measurement location
AB - We numerically investigate the structures of the near-plate temperature profiles close to the bottom and top plates of turbulent Rayleigh-Bénard flow in a cylindrical sample at Rayleigh numbers Ra=108 to Ra=2×1012 and Prandtl numbers Pr=6.4 and Pr=0.7 with the dynamical frame method [ Zhou and Xia Phys. Rev. Lett. 104 104301 (2010)], thus extending previous results for quasi-two-dimensional systems to three-dimensional systems. The dynamical frame method shows that the measured temperature profiles in the spatially and temporally local frame are much closer to the temperature profile of a laminar, zero-pressure gradient boundary layer (BL) according to Pohlhausen than in the fixed reference frame. The deviation between the measured profiles in the dynamical reference frame and the laminar profiles increases with decreasing Pr, where the thermal BL is more exposed to the bulk fluctuations due to the thinner kinetic BL, and increasing Ra, where more plumes are passing the measurement location
KW - METIS-284413
KW - IR-79685
U2 - 10.1103/PhysRevE.85.027301
DO - 10.1103/PhysRevE.85.027301
M3 - Article
SN - 1539-3755
VL - 85
JO - Physical review E: Statistical, nonlinear, and soft matter physics
JF - Physical review E: Statistical, nonlinear, and soft matter physics
IS - 2
M1 - 027301
ER -