Velocity Profiles and Friction Factors in Turbulent Pipe Flows

2020 ◽  
pp. 39-67
Author(s):  
Aroon Shenoy
Keyword(s):  
Velocity Profiles ◽  
Pipe Flows ◽  
Friction Factors

Velocity profiles in constant-acceleration pipe flows

1988 ◽  
Author(s):  
PAUL LEFEBVRE ◽  
KENNETH LAPOINTE
Keyword(s):  
Velocity Profiles ◽  
Constant Acceleration ◽  
Pipe Flows

Friction factor analysis for a nanofluid circulating in a microchannel filled with a homogeneous porous medium

2022 ◽  
Author(s):  
Francisco Fernando Hernandez ◽  
Federico Mendez ◽  
Jose Joaquin Lizardi ◽  
Ian Guillermo Monsivais
Keyword(s):  
Porous Medium ◽  
Friction Factor ◽  
Porous Matrix ◽  
Velocity Profiles ◽  
Momentum Equation ◽  
Volumetric Concentration ◽  
Forchheimer Equation ◽  
Viscosity Models ◽  
Friction Factors ◽  
Homogeneous Porous Medium

Abstract This work presents the numerical solution for different velocity profiles and friction factors on a rectangular porous microchannel fully saturated by the flow of a nanofluid introducing different viscosity models, including one nanofluid density model. The Darcy-Brinkman-Forchheimer equation was used to solve the momentum equation in the porous medium. The results show that the relative density of the fluid, the nanoparticle diameters and their volumetric concentration have a direct influence on the velocity profiles only when the inertial effects caused by the presence of the porous matrix are important. Finally, it was found that only viscosity models that depend on temperature and nanoparticle diameter reduce the friction factor by seventy percent compared to a base fluid without nanoparticles; furthermore, these models show a velocity reduction of even ten percent along the symmetry axis of the microchannel.

Highly viscous liquid flow in pipeline components

2005 ◽  
Vol 219 (3) ◽  
pp. 267-281 ◽  
Author(s):  
D A McNeil ◽  
A D Stuart
Keyword(s):  
Reynolds Number ◽  
Viscous Liquid ◽  
Liquid Flow ◽  
Flow Behaviour ◽  
Number Range ◽  
Pipe Flows ◽  
Discharge Coefficients ◽  
Friction Factors ◽  
Loss Coefficients ◽  
Globe Valve

Water and an aqueous glycerine solution were used to obtain liquids with nominal viscosities of 1 and 550 mPa s. These fluids were used to obtain friction factors for pipe flows, discharge coefficients for orifice plates and nozzles, and loss coefficients for an abrupt enlargement, a nozzle, an orifice plate, and a globe valve in the Reynolds number range 10-200. Existing methods are shown to be adequate for the prediction of friction factors and discharge coefficients, but inadequate for the prediction of loss coefficients. Insight is given into the flow behaviour that is associated with the loss coefficients.

Friction factors in the theory of bifurcating Poiseuille flow through annular ducts

1974 ◽  
Vol 66 (1) ◽  
pp. 189-207 ◽  
Author(s):  
D. D. Joseph ◽  
T. S. Chen
Keyword(s):  
Friction Factor ◽  
Poiseuille Flow ◽  
Bifurcation Theory ◽  
Frequency Change ◽  
Pipe Flows ◽  
Friction Factors ◽  
Flow Through ◽  
Number Curve ◽  
Time Periodic ◽  
Time Periodic Solution

The objective of this paper is to show how to formulate a bifurcation theory for pipe flows in terms of the friction factor. We compute the slope of the friction factor vs. Reynolds number curve and the frequency change for the time-periodic solution which bifurcates from Poiseuille flow through annular ducts.

scholarly journals Turbulent flows in channels and pipes

2007 ◽  
Vol 29 (3) ◽  
pp. 385-396
Author(s):  
Khanh Le Chau
Keyword(s):  
Variational Principle ◽  
Viscous Fluid ◽  
Turbulent Flows ◽  
Good Accuracy ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Pipe Flows ◽  
High Reynolds Numbers ◽  
Friction Factors ◽  
High Reynolds

A variational principle for channel and pipe flows of incompressible viscous fluid is proposed. For low Reynolds numbers this variational principle reduces to the principle of minimum dissipation. For high Reynolds numbers it enables one to calculate the velocity profiles and the corresponding friction factors with reasonably good accuracy.

Assessment of the Equivalent Sandbed Roughness and the Interfacial Friction Factor in Hole Cleaning With Water in a Fully Eccentric Horizontal Annulus

SPE Journal ◽  
2018 ◽  
Vol 23 (05) ◽  
pp. 1748-1767 ◽  
Author(s):  
Majid Bizhani ◽  
Ergun Kuru
Keyword(s):  
Friction Factor ◽  
Fluid Velocity ◽  
Velocity Profiles ◽  
Primary Objective ◽  
Bedload Transport ◽  
Interfacial Friction ◽  
Erosion Process ◽  
Hole Cleaning ◽  
Bed Erosion ◽  
Friction Factors

Summary In this study, we have investigated the turbulent flow of water over the sandbed deposited in a horizontal eccentric annulus. The primary objective was to determine the effect of the presence of a sandbed on the parameters strongly involved in the bed-erosion process, such as the local fluid-velocity profiles near the interface, the equivalent sandbed roughness, and the average and the interfacial friction factors. The particle-image-velocimetry (PIV) technique was used to measure the velocity distribution at the water/sandbed interface. The bedload transport of particles caused an abrupt increase in the equivalent sandbed roughness. Analyses of the velocity profiles in the wall units confirmed that the sandbed roughness is variable and can be several times greater than the mean particle size. The interfacial ( fi) and the average friction factors ( fa) were evaluated and compared with flow under the stationary-bed and the bedload-transport conditions. The interfacial friction factor increased dramatically at the onset of the bed erosion. We have also found that depending on the bed height (or the surface area of the bed at the interface), the interfacial friction factor can be significantly different from the average friction factor. The results presented here provide much-needed experimental data for the validation of the mechanistic, semimechanistic (empirical), and numerical [computational-fluid-dynamics (CFD)] models of the bed erosion process. The major conclusion of the study is that the difference between the average and interfacial friction factors should be taken into account for more-realistic multilayer modeling of the hole cleaning.

Rapid Transition to Turbulence in Pipe Flows Accelerated From Rest

2003 ◽  
Vol 125 (6) ◽  
pp. 1072-1075 ◽  
Author(s):  
David Greenblatt ◽  
Edward A. Moss
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Laminar Boundary Layer ◽  
Pipe Flow ◽  
Velocity Profiles ◽  
Transition To Turbulence ◽  
Acceleration Phase ◽  
Pipe Flows ◽  
Rapid Transition ◽  
Rapid Deceleration

Rapid transition to turbulence in a pipe flow, initially at rest, was achieved by temporally accelerating the flow and then sharply decelerating it to its final Reynolds number. The acceleration phase was characterized by the growth of a laminar boundary layer close to the wall. The subsequent rapid deceleration resulted in inflectional velocity profiles near the wall, followed immediately by transition to turbulence. The time taken to transition was significantly less than the time to transition in a pipe flow monotonically accelerated to the same Reynolds number. Transition is intrinsically different to that observed in oscillatory pipe flows, but is qualitatively similar to pipe flows decelerated to rest.

Oseen Approximation for Packed Bed Flow - Velocity Profiles and Friction Factors

1972 ◽  
Vol 15 (3) ◽  
pp. 0543-0547 ◽  
Author(s):  
W. M. Carson and G. L. Bloomsburg
Keyword(s):  
Flow Velocity ◽  
Packed Bed ◽  
Velocity Profiles ◽  
Friction Factors ◽  
Oseen Approximation

scholarly journals Concave-Wall Laminar Heat Transfer and Görtler Vortex Structure: Effects of Pre-Curvature Boundary Layer and Favourable Pressure Gradients

1990 ◽  
Author(s):  
R. I. Crane ◽  
H. Umur
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Heat Transfer Enhancement ◽  
Vortex Structure ◽  
Velocity Profiles ◽  
Transfer Enhancement ◽  
Mean Velocity ◽  
Concave Wall ◽  
Friction Factors ◽  
Gradient Enhancement

The mean velocity field in the boundary layer and the streamwise and spanwise distributions of heat transfer coefficient have been measured on a concave wall in the presence of naturally-generated Görtler vortices, with and without a preceding flat wall. In near-zero pressure gradient, enhancement of the streamwise-averaged heat transfer above flat surface levels was associated with the attainment of a Görtler number of around ten, as found in previous experiments in a different flow facility with higher wall curvature, but occurred before the onset of severe distortion in the velocity profiles. Velocity gradient parameters K of 0·20 × 10−6 and 0·75 × 10−6 resulted in a more regular vortex structure, with spanwise averaged heat transfer reaching two to three times predicted levels. At K = 1·8 × 10−6, vortex amplification was suppressed to such an extent that no significant heat transfer enhancement took place. Comparison of measured Stanton numbers with those derived from skin friction factors (obtained from velocity profiles) suggested that the heat transfer enhancement is not simply a result of fuller velocity profiles in vortex downwash regions.

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