Micro-scale transport - Non-continuum thermophysical property variation effects on heat and momentum transfer

1997 ◽  
Author(s):  
J. Baker ◽  
M. Calvert ◽  
J. Baker ◽  
M. Calvert
Keyword(s):  
Momentum Transfer ◽  
Thermophysical Property ◽  
Property Variation ◽  
Micro Scale ◽  
Heat And Momentum Transfer

HEAT AND MOMENTUM TRANSFER BY VORTEX IN MIXING LAYER

1998 ◽  
Author(s):  
A. Jazdauskas ◽  
R. Slezas ◽  
Anupras Slanciauskas ◽  
Algis Dziugys
Keyword(s):  
Momentum Transfer ◽  
Mixing Layer ◽  
Heat And Momentum Transfer

Forced Turbulent Convection Along Heated and Cooled Walls with Variable Fluid Properties

2021 ◽  
Author(s):  
Lorenzo Sufrà ◽  
Helfried Steiner
Keyword(s):  
Isotropic Turbulence ◽  
Turbulence Models ◽  
Turbulent Pipe Flow ◽  
Wall Friction ◽  
Effect Of Temperature ◽  
Inertial Subrange ◽  
Property Variation ◽  
Fluid Properties ◽  
Applied Approach ◽  
Heat And Momentum Transfer

Abstract The effect of temperature depending material properties on heat and momentum transfer along heated/cooled walls in turbulent pipe flow was investigated using direct numerical simulations (DNS). For the considered thermal wall conditions, always associated with a molecular Prandtl number well over unity Prw = 10, the significantly dampened/enhanced turbulent motion caused by the increase/decrease of the viscosity with distance to the heated/cooled wall, turned out to clearly dominate over the opposite trend of the enthalpy fluctuations. The Nusselt number and, quantitatively less pronounced, the wall friction coefficient are accordingly decreased/increased for the heated/cooled case. A comparison against a well established Nu-correlation unveils the limits of the generally applied approach, which is essentially based on uniform bulk flow conditions and subsequently modified accounting for material property variation, when applied to heated and cooled conditions. An enhanced disparity of the turbulent normal stresses is observed inside the inertial subrange for the heated case, indicating a stronger deviation from isotropic turbulence, which possibly challenges mostly isotropic standard turbulence models.

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