this paper presents a three-dimensional numerical investigation carried out in turbulent forced convection in a tube with helical ribs. enhancement of heat transfer using helically corrugated tubes has beenstudied experimentally by many researchers but there exist a few published numerical analyses results. the paper also introduces the results of heat transfer and friction factor data for inco...

Homogeneous anisotropict urbulence simulations are used to determine off-diagonal componentso fthe Reynolds stress tensora nd itsp arameterizationi nt erms of turbulentv iscosity and Λ-effect.T he turbulence is forced in an anisotropic fashion by enhancing thestrengthofthe forcing in thevertical direction. TheCoriolis force is included with arotationaxis inclined relativetothe vertical directio...

For thermal mixed-convection flows, the Nusselt number is a function of Reynolds number, Grashof number and the angle between the forcedand natural-convection directions. We consider flow over a heated cylinder for which there is no universal correlation that accurately predicts Nusselt number as a function of these parameters, especially in opposing-convection flows, where the natural convecti...

Several researches dealing with the single-phase forced convection heat transfer inside micro channels have been published in the past decades. The performance of liquid flow has been proved that agree with the conventional correlations very well (Yang and Lin [2007]). However, owing to the low heat transfer coefficient of gaseous flow, it is more difficult to eliminate the effects of thermal s...

Heat and vapour convective surface coefficients are required in practically all heat and vapour transport calculations. In building envelope research, such coefficients are often assumed constants for a set of conditions. Heat transfer surface coefficients are often determined using empirical correlations based on measurements of different geometry and flows. Vapour transfer surface coefficient...

We present a numerical study of Rayleigh-Bénard convection disturbed by a longitudinal wind. Our results show that under the action of the wind, the vertical heat flux through the cell initially decreases, due to the mechanism of plume sweeping, and then increases again when turbulent forced convection dominates over the buoyancy. As a result, the Nusselt number is a nonmonotonic function of th...