Turbulent friction factor and velocity profile in smooth annuli

1971 ◽  
Vol 23 (1) ◽  
pp. 446-458
Author(s):  
D. N. Roy ◽  
U. Gangopadhay
Keyword(s):  
Velocity Profile ◽  
Friction Factor ◽  
Turbulent Friction

Correlations for the friction factor and velocity profile in the transition region for flow in sand-roughened pipes

1964 ◽  
Vol 19 (6) ◽  
pp. 423-425 ◽  
Author(s):  
R.M. Nedderman ◽  
C.J. Shearer
Keyword(s):  
Velocity Profile ◽  
Friction Factor ◽  
Transition Region

Turbulent Friction Factor for a Rod Bundle in Consideration of a Subchannel Geometry

2002 ◽  
Author(s):  
Joo Hwan Park ◽  
Chang Joon Jeong ◽  
Myung Seung Yang ◽  
Dong Suk Oh
Keyword(s):  
Friction Factor ◽  
Measurement Data ◽  
Experimental Results ◽  
Flow Area ◽  
Theoretical Derivation ◽  
Turbulent Friction ◽  
Law Of The Wall ◽  
Rod Bundle ◽  
Two Parameters ◽  
Geometry Parameter

A generalized turbulent friction factor for a rod bundle was developed based on “Law of the Wall” for a tube. It was included two parameters which are one parameter of hydraulic diameter and flow area of a subchannel and rod bundle and another parameter (called geometry parameter hereinafter) of subchannel configuration and pitch-to-diameter ratio (P/D) for a single subchannel. The turbulent geometry parameter for a single subchannel has been used as a constant on the previous works but it was found to be dependent on subchannel shapes and P/D from the present work. Hence, it was modeled as a function of the subchannel shapes and P/D from 1.0 to 1.5. The turbulent geometry parameters for single subchannels were validated by the theoretical derivation of a triangular and square subchannel. Those are compared and agreed well with the previous measurement data for 4 kinds of subchannel types such as a triangular, a square, a wall and a corner subchannel. The present model of turbulent friction factor for a rod bundle included the turbulent geometry parameter has been compared with the various experimental results for circular tubes and hexagonal tubes with various rod numbers. The predicted turbulent friction factors for those rod bundles were agreed excellently with experimental results.

The Effect of a Longitudinal Magnetic Field on Pipe Flow of Mercury

1961 ◽  
Vol 83 (4) ◽  
pp. 445-453 ◽  
Author(s):  
Samuel Globe
Keyword(s):  
Magnetic Field ◽  
Reynolds Number ◽  
Friction Factor ◽  
Pipe Flow ◽  
Longitudinal Magnetic Field ◽  
Hartmann Number ◽  
Characteristic Length ◽  
Axial Magnetic Field ◽  
Turbulent Friction ◽  
The Magnetic Field

An experimental investigation has been made of the effect of an axial magnetic field on transition from laminar to turbulent flow and on the turbulent friction factor for pipe flow of mercury. Magnetic-flux densities up to 5700 gauss were obtained with a water-cooled solenoid. Pipes of glass and aluminum were used of approximately 0.1 to 0.2 in. diam. The maximum Hartmann number, with the hydraulic radius (half the actual radius) taken as the characteristic length, was about 20. Measurements were made of the pressure gradient and velocity of flow. The transition Reynolds number was determined from the curve of friction factor against Reynolds number. The results show an increasing value of minimum transition Reynolds number with Hartmann number. The magnetic field also brought about a decrease in the turbulent friction factor and corresponding shear force at the wall.

Roughness effects of commercial steel pipe in turbulent flow: universal scaling

2013 ◽  
Vol 40 (2) ◽  
pp. 188-193 ◽  
Author(s):  
Noor Afzal
Keyword(s):  
Surface Roughness ◽  
Velocity Profile ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Steel Pipe ◽  
Roughness Effects ◽  
Universal Scaling ◽  
Commercial Steel ◽  
The Mean ◽  
Grain Roughness

The mean turbulent flow over a transitional rough commercial steel pipe is considered in terms of alternate inner roughness variables. The matching of inner layer and outer layer in the overlap region leads to the universal log laws for velocity profile and friction factor, explicitly independent of surface roughness of all kinds. The roughness function, for commercial steel pipe differs from inflectional (sand grain) roughness. The traditional wall law and friction factor depends on type of surface roughness.

Laminar, Transitional and Turbulent Friction Factors for Gas Flows in Smooth and Rough Microtubes

2008 ◽  
Author(s):  
Marco Lorenzini ◽  
Gian Luca Morini ◽  
Sandro Salvigni
Keyword(s):  
Reynolds Number ◽  
Friction Factor ◽  
Turbulent Regime ◽  
Turbulent Friction ◽  
Compressibility Effect ◽  
Flow Acceleration ◽  
Friction Factors ◽  
Macro Scale ◽  
Fully Developed Turbulent Flow ◽  
Microscale Transport

Theoretical and experimental works on microscale transport phenomena have been carried out in the past decade in the attempt to analyse possible new effects and to assess the influence of scaling on the classical correlations which are used in macro-scale heat and fluid flow, following the need to supply engineers with reliable correlations to be used in the design of micro-scale devices. These results were sometimes in mutual contrast, as is the case for the determination of the friction factor, which has been found to be lower, higher or comparable to that for macroscopic channels, depending on the researchers. In this work the compressible flow of nitrogen inside circular microchannels from 26 μm to 508 μm in diameter and with different surface roughness (<1%) is investigated for the whole range of flow conditions: laminar, transitional and turbulence. Over 5000 experimental data have been collected and analysed. The data confirmed that in the laminar regime the agreement with the conventional theory is very good in terms of friction factors both for rough and smooth microtubes. For the smaller microchannels (<100 μm) when Re is greater than 1300 the friction factor tends to deviate from the Poiseuille law because the flow acceleration due to compressibility effect gains in importance. The transitional regime was found to start no earlier than at values of the Reynolds number around 1800–2000. Both smooth and sudden changes in the flow regime have been found, as reported for conventional tubes. Fully developed turbulent flow was attained with both smooth and rough tubes, and the results for smooth tubes seem to confirm Blasius’s relation, while for rough tubes the Colebrook’s correlation is found to be only partially in agreement with the experimental friction factors. In the turbulent regime the dependence of the friction factor on the Reynolds number is less pronounced for microtubes with respect to the prediction of the Colebrook’s correlation and the friction factor tends only to depend on the microtube relative roughness.

Reliability of friction factor in turbulent pipe flow - Investigation from mean velocity profile

2016 ◽  
Vol 2016 (0) ◽  
pp. 1006
Author(s):  
Noriyuki FURUICHI ◽  
Yoshiya TERAO ◽  
Yuki WADA ◽  
Yoshiyuki TSUJI
Keyword(s):  
Velocity Profile ◽  
Friction Factor ◽  
Pipe Flow ◽  
Turbulent Pipe Flow ◽  
Mean Velocity ◽  
Flow Investigation

A Heat-Mass Transfer Analogy Applied to Fully Developed Turbulent Flow in an Annulus

1971 ◽  
Vol 13 (4) ◽  
pp. 286-292 ◽  
Author(s):  
J. S. Lewis
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Velocity Profile ◽  
Friction Factor ◽  
Heat Mass Transfer ◽  
Eddy Diffusivity ◽  
Round Tube ◽  
Fully Developed Turbulent Flow ◽  
The Difference

A heat-mass transfer analogy based on the ‘universal’ velocity profile applied to an annulus is compared with analogy values based on similar but more sophisticated expressions for the eddy diffusivity and hence velocity profile. The difference between these analogy values and those of Chilton and Colburn (I)† are noted to be appreciable and to increase with increasing Reynolds number. Heat transfer predictions from mass transfer measurements using ‘universal’ velocity profile type analogies are compared with established results. Friction factor measurements were made and found to be up to 10 per cent higher than the values for flow in a round tube at the corresponding Reynolds number.

Some Deductions from Bowen's Non-Newtonian Turbulent Correlation

1967 ◽  
Vol 9 (5) ◽  
pp. 414-416
Author(s):  
J. Harris
Keyword(s):  
Reynolds Number ◽  
Velocity Profile ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Effective Viscosity ◽  
Empirical Correlation ◽  
Dynamic Similarity ◽  
Flow Through

Starting from Bowen's empirical correlation for non-Newtonian turbulent flow through pipes, deductions are made about the form of the velocity profile, the effective viscosity, the Reynolds number for dynamic similarity and finally the associated form of the friction factor-Reynolds number correlation.

Friction factor and mean velocity profile for pipe flow at high Reynolds numbers

2015 ◽  
Vol 27 (9) ◽  
pp. 095108 ◽  
Author(s):  
N. Furuichi ◽  
Y. Terao ◽  
Y. Wada ◽  
Y. Tsuji
Keyword(s):  
Velocity Profile ◽  
Friction Factor ◽  
Pipe Flow ◽  
Reynolds Numbers ◽  
Mean Velocity ◽  
High Reynolds Numbers ◽  
High Reynolds
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