Boundary layer analysis in turbulent Rayleigh-Bénard convection in air: experiment versus simulation.

Buoyancy statistics in moist turbulent Rayleigh–Bénard convection

We study shallow moist Rayleigh–Bénard convection in the Boussinesq approximation in three-dimensional direct numerical simulations. The thermodynamics of phase changes is approximated by a piecewise linear equation of state close to the phase boundary. The impact of phase changes on the turbulent fluctuations and the transfer of buoyancy through the layer is discussed as a function of the Rayl...

Structure of the thermal boundary layer for turbulent Rayleigh-Bénard convection of air in a long rectangular enclosure.

Measurements of the temperature distribution were performed in the upper (cold) boundary layer of a rectangular Rayleigh-Bénard cell with aspect ratios Gamma(x) = 5 and Gamma(y) = 1 using air with Prandtl number Pr = 0.71 as the working fluid. The range of investigated Rayleigh numbers was from Ra approximately 6 x 10(7) to Ra approximately 6 x 10(8), and the measurements were taken at two diff...

Spectral analysis of boundary layers in Rayleigh-Bénard convection.

A combined experimental and numerical study of the boundary layer in a 4:1 aspect-ratio Rayleigh-Bénard cell over a four-decade range of Rayleigh numbers has been undertaken aimed at gaining a better insight into the character of the boundary layers. The experiments involved the simultaneous laser Doppler anemometry measurements of fluid velocity at two locations, i.e., in the boundary layer an...

Sheared boundary layers in turbulent Rayleigh-Bénard convection.

Boundary Layer Structure in Turbulent Rayleigh-bénard Convection in Air

We present Particle Image Velocimetry measurements in the boundary layer in turbulent Rayleigh-Bénard (RB) convection for the Rayleigh number RR = 1.4 × 1010 and the Prandtl number PP = 0.7 . The measurements have been undertaken in a large-scale RB experiment 7.15 m in diameter and 6.30 m in height which is called the “Barrel of Ilmenau”. They give detailed insight into the near-wall flow fiel...