We analyze the global transport properties of turbulent Taylor-Couette flow in the strongly turbulent regime for independently rotating outer and inner cylinders, reaching Reynolds numbers of the inner and outer cylinders of Re(i) = 2×10(6) and Re(o) = ±1.4×10(6), respectively. For all Re(i), Re(o), the dimensionless torque G scales as a function of the Taylor number Ta (which is proportional t...

In turbulent thermal convection in cylindrical samples with an aspect ratio Γ≡D/L (D is the diameter and L the height), the Nusselt number Nu is enhanced when the sample is rotated about its vertical axis because of the formation of Ekman vortices that extract additional fluid out of thermal boundary layers at the top and bottom. We show from experiments and direct numerical simulations that th...

We report measurements of the Nusselt number, Nu, in turbulent thermal convection in a cylindrical container of aspect ratio 4. The highest Rayleigh number achieved was Ra=2× 10. Except for the last half a decade or so of Ra, experimental conditions obey the Boussinesq approximation accurately. For these conditions, the data show that the logNu–logRa slope saturates at a value close to 1/3, as ...

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...

This paper describes experimental investigations on convective heat transfer in counter flow double pipe exchanger under transverse vibration for single-phase with twisted tape insert the inner tube. Experiments were conducted inserted twist ratio from 7 to 17, amplitude 23 69 mm, frequency 20 100 Hz and Reynolds number (Re) changing 10710 21420. A maximum gain of 91% Nusselt (Nu) was obtained ...

This computational fluid dynamic analysis attempts to simulate the incompressible steady fluid flow and heat transfer in a solar air channel with wall-mounted baffles. Two ꞌSꞌ-shaped baffles, having different orientations, i.e., ꞌSꞌ-upstream and ꞌSꞌ-downstream, were inserted into the channel and fixed to the top and bottom walls of the channel in a periodically staggered manner to develop vorti...

Two main controlling factors of ice crystal growth are the heat and (gaseous) mass transfers, H&MT, as characterized by the Nusselt number (Nu) for heat and the Sherwood (Sh) number for mass. Nu and Sh express the increase of the molecular diffusions by the relative motions of the particles in air as characterized by the Reynolds number (Re). Traditionally Nu is assumed to be identical to Sh. P...

The pattern and style of mantle convection govern the thermal evolution, internal dynamics, and large-scale surface deformation of the terrestrial planets. In order to characterize the nature of heat transport and convective behaviour at Rayleigh numbers, Ra, appropriate for planetary mantles (between 104 and 108), we perform a set of laboratory experiments. Convection is driven by a temperatur...