A model sheep, made from metal cylinders and hemispheres, was heated electrically. Heat loss by forced convection in a wind tunnel was analysed in terms of the dependence of the Nusselt number (Nu) on Reynolds number (Re). For a bare trunk Nu = 0.095 J?e0-684, but with fleece covering the trunk to a depth of 3.5 cm, Nu = 0.0112 °-875 when the mean radiative temperature of the coat was taken as ...

A model sheep, made from metal cylinders and hemispheres, was heated electrically. Heat loss by forced convection in a wind tunnel was analysed in terms of the dependence of the Nusselt number (Nu) on Reynolds number (Re). For a bare trunk Nu = 0.095 Re0.684, but with fleece covering the trunk to a depth of 3.5 cm, Nu = 0.0112 Re0.875 when the mean radiative temperature of the the coat was take...

We report experimental results for the heat transport, as expressed by the Nusselt number Nu, by turbulent Rayleigh-Bénard convection in a cylindrical sample of aspect ratio Γ ≡ D/L = 0.50 (D = 1.12 m is the diameter and L = 2.24 m the height). The measurements are for the Rayleigh-number range 10 <∼ Ra <∼ 10 15 and for a Prandtl number Pr ' 0.86. At these large Ra the results were exceptionall...

In present work forced convection flow in a channel partly filled with a porous media under asymmetric heat flux boundary condition has been investigated. The porous material is distributed on the one wall. Darcy–Brinkman and LTNE model have been assumed in order to solve momentum and energy equations, respectively. Fully developed conditions are considered in order to solve velocity and the te...

In this study, an adaptive neuro-fuzzy inference system (ANFIS) was developed to determine the Nusselt number (Nu) along a wavy wall in a lid-driven cavity under mixed convection regime. Firstly, the main data set of input/output vectors for training, checking and testing of the ANFIS was prepared based on the numerical results of the lattice Boltzmann method (LBM). Then, the ANFIS was develope...

Measurements of heat transport, as expressed by the Nusselt number Nu, are reported for turbulent Rayleigh-Bénard convection of water containing up to 120 ppm by weight of poly-[ethylene oxide] with a molecular weight of 4x10{6} g/mole. Over the Rayleigh number range 5x10{9} less than or approximately Ra less than or approximately 7x10{10} Nu is smaller than it is for pure water by up to 10%.

Graetz and Nusselt studied heat transfer between a developed laminar fluid flow and a tube at constant wall temperature. Here, we extend the Graetz–Nusselt problem to dense fluid flows with partial wall slip. Its limits correspond to the classical problems for no-slip and no-shear flow. The amount of heat transfer is expressed by the local Nusselt number Nux, which is defined as the ratio of co...

We report results from Direct Numerical Simulation (DNS) of rotating Rayleigh-Bénard convection, regarding the scaling of heat transfer with the Rayleigh number for rotating systems at a fixed rate of rotation. The Prandtl number, Pr = 6.4, is kept constant. We perform simulations, using a spectral element method, for Rayleigh numbers Ra from 10 to 10, and Rossby numbers Ro from 0.09 to∞. We fi...

We report on turbulent thermal convection of a nematic liquid crystal heated from below in a cylindrical cell with an aspect ratio (diameter/height) equal to 0.500 for Rayleigh numbers 2×10 < ∼ Ra < ∼ 3 × 10. The Nusselt number Nu as a function of Ra did not differ significantly from that of an isotropic fluid. In a vertical magnetic field H we found Nu(H)/Nu(0) = 1 + a(Ra)H with a(Ra) = 0.24Ra...

We investigate the influence of the thermal properties of the boundaries in turbulent Rayleigh-Bénard convection on analytical bounds on convective heat transport. Using the Doering-Constantin background flow method, we systematically formulate a bounding principle on the Nusselt-Rayleigh number relationship for general mixed thermal boundary conditions of constant Biot number η which continuou...