Fully developed periodic turbulent pipe flow. Part 1. Main experimental results and comparison with predictions

1983 ◽  
Vol 137 ◽  
pp. 31-58 ◽  
Author(s):  
S. W. Tu ◽  
B. R. Ramaprian
Keyword(s):  
Experimental Data ◽  
Pipe Flow ◽  
Shear Flows ◽  
Volumetric Flow Rate ◽  
Intermediate Frequency ◽  
Turbulent Pipe Flow ◽  
Experimental Results ◽  
Turbulent Shear ◽  
Relevant Parameter ◽  
Flow Modulation

The present paper is the first part of a two-part report on a detailed investigation of periodic turbulent pipe flow. In this investigation, experimental data on instantaneous velocity and wall shear stress were obtained at a mean Reynolds number of 50000 in a fully developed turbulent pipe flow in which the volumetric flow rate was varied sinusoidally with time around the mean. Two oscillation frequencies at significant levels of flow modulation were studied in detail. The higher of these frequencies was of the order of the turbulent bursting frequency in the flow, and the other can be regarded as an intermediate frequency at which the flow still departed significantly from quasi-steady behaviour. While a few similar experiments have been reported in the recent literature, the present study stands out from the others in respect of the flow regimes investigated, the magnitude of flow modulation, the detailed nature of the measurements and most importantly the identification of a relevant parameter to characterize unsteady shear flows. The present paper contains the main experimental results and comparisons of these results with the results of a numerical calculation procedure which employs a well-known quasi-steady turbulence closure model. The experimental data are used to study the manner in which the time-mean, the ensemble-averaged and the random flow properties are influenced by flow oscillation at moderate to high frequencies. In addition, the data are also used to bring out the capability and limitations of quasi-steady turbulence modelling in the prediction of unsteady shear flows. A further and more detailed analysis of the experimental data, results of some additional experiments and a discussion on the characterization of turbulent shear flows are provided in Part 2 (Ramaprian & Tu 1983).

Fully developed periodic turbulent pipe flow. Part 2. The detailed structure of the flow

1983 ◽  
Vol 137 ◽  
pp. 59-81 ◽  
Author(s):  
B. R. Ramaprian ◽  
S. W. Tu
Keyword(s):  
Flow Structure ◽  
Pipe Flow ◽  
Shear Flows ◽  
Stokes Number ◽  
Turbulent Pipe Flow ◽  
Turbulent Shear ◽  
Turbulence Structure ◽  
Turbulent Shear Flows ◽  
Flow Part ◽  
Oscillation Frequencies

The main experimental results of the study of periodic turbulent pipe flow have been described in Part 1 of this report. In this second part, these experimental data are examined in greater detail to understand the effect of imposed oscillation on the flow structure, at moderate to large oscillation frequencies. Data on phase and amplitude and energy spectrum are used to study the effect of the imposed oscillation on the turbulence structure at these interactive frequencies of oscillation. Additional experiments which were performed to study the effect of oscillation frequency on the flow structure are also reported. Based on the present observations as well as on the data from other sources, it is inferred that turbulent shear flows respond very differently from laminar shear flows to imposed unsteadiness. A turbulent Stokes number relevant for characterizing the unsteady turbulent shear flows is identified and used to classify such flows.

Wall Suction Effects on the Structure of Fully Developed Turbulent Pipe Flow

1996 ◽  
Vol 118 (1) ◽  
pp. 33-39 ◽  
Author(s):  
D. Sofialidis ◽  
P. Prinos
Keyword(s):  
Shear Stress ◽  
Pipe Flow ◽  
Stokes Equations ◽  
Turbulent Pipe Flow ◽  
Turbulent Shear ◽  
Experimental Measurements ◽  
Wall Region ◽  
Wall Suction ◽  
Law Of The Wall ◽  
Near Wall

The effects of wall suction on the structure of fully developed pipe flow are studied numerically by solving the Reynolds averaged Navier-Stokes equations. Linear and nonlinear k-ε or k-ω low-Re models of turbulence are used for “closing” the system of the governing equations. Computed results are compared satisfactorily against experimental measurements. Analytical results, based on boundary layer assumptions and the mixing length concept, provide a law of the wall for pipe flow under the influence of low suction rates. The analytical solution is found in satisfactory agreement with computed and experimental data for a suction rate of A = 0.46 percent. For the much higher rate of A = 2.53 percent the above assumptions are not valid and analytical velocities do not follow the computed and experimental profiles, especially in the near-wall region. Near-wall velocities, as well as the boundary shear stress, are increased with increasing suction rates. The excess wall shear stress, resulting from suction, is found to be 1.5 to 5.5 times the respective one with no suction. The turbulence levels are reduced with the presence of the wall suction. Computed results of the turbulent shear stress uv are in close agreement with experimental measurements. The distribution of the turbulent kinetic energy k is predicted better by the k-ω model of Wilcox (1993). Nonlinear models of the k-ε and k-ω type predict the reduction of the turbulence intensities u’, v’, w’, and the correct levels of v’ and w’ but they underpredict the level of u’.

Predicting Drag Reduction in Turbulent Pipe Flow With Relaxation Time of Polymer Additives

2018 ◽  
Author(s):  
Xin Zhang ◽  
Xili Duan ◽  
Yuri Muzychka ◽  
Zongming Wang
Keyword(s):  
Experimental Data ◽  
Relaxation Time ◽  
Drag Reduction ◽  
Pipe Flow ◽  
Polymer Concentration ◽  
Weissenberg Number ◽  
Turbulent Pipe Flow ◽  
Dimensionless Number ◽  
Polymer Additives ◽  
Dilute Solution

This paper presents an experimental study on drag reduction induced by PEO (Polyethylene oxide) in a fully turbulent pipe flow. The objective of this work is to develop a correlation to predict drag reduction using the relaxation time of the polymer additives under dilute solution conditions, i.e., the polymer concentration is less than the overlap concertation. This paper discusses the meaning of relaxation time of polymers, and why the Weissenberg number, a dimensionless number that is related to the relaxation time and shear rate, is independent on the concentration in the dilute solution. Experimental data of drag reduction in a pipe flow are obtained from measurements using a flow loop. A correlation to predict drag reduction with the Weissenberg number and polymer concentration is established and a good agreement is shown between the predicted values and experimental data. The new correlation using the Weissenberg number and polymer concentration is shown to cost less to develop than one using the Reynolds number, in which larger pipes or higher flow rates are required.

RANS and LES of Particle Dispersion in Turbulent Pipe Flow: Simulations Versus Experimental Results

2006 ◽  
Author(s):  
Abdallah S. Berrouk ◽  
Alexandre Douce ◽  
Dominique Laurence ◽  
James J. Riley ◽  
David E. Stock
Keyword(s):  
Stochastic Modeling ◽  
Pipe Flow ◽  
Fluid Velocity ◽  
Particle Dispersion ◽  
Solid Particles ◽  
Turbulent Pipe Flow ◽  
Experimental Results ◽  
Experimental Measurements ◽  
Vertical Pipe ◽  
Numerical Predictions

Turbulent transport and dispersion of inertial particles in fully-developed turbulent vertical pipe flow has been investigated (Reτ = 2,200, based on the friction velocity and the pipe diameter) using two approaches: large-eddy simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) both employing Lagrangian tracking of a dilute suspension of particles (glass beads in air with different Stokes’ numbers, namely 0.022 and 2.8). Detailed numerical simulations are performed in order to: (a) assess the capabilities of these two approaches to match the experimental measurements of Arnason and Stock [1, 2]; and (b) validate the extension of the stochastic approach based on Langevin modeling used in a RANS framework to the generation of sub grid-scale fluctuating velocities as seen by solid particles in LES. Results for the particle dispersion coefficient and preferential distribution of particles in different sections of the vertical pipe as well as streamwise and radial particle velocities, are computed and compared to the results of the experimental measurements. The following conclusions are drawn. (a) Both RANS and LES, using stochastic modeling for the fluid velocity, are seen to predict reasonably well the dispersion of solid particles with different Stokes’ numbers in a high Reynolds number, nonhomogeneous and anisotropic turbulent flow. (b) The extension of stochastic modeling based on the Langevin equation to the construction of the subgrid-scale fluctuating velocity field as seen by the particles is successful; it contributes to the better results obtained, compared to RANS results, especially for those predicted for the small particles. (c) As shown in experimental results [1, 2] and demonstrated by theoretical studies [3, 4], the numerical predictions supported the conclusions that large inertia particles can disperse faster than small inertia particles, depending on the combined effects of inertia and drift parameters.

A three-dimensional law of the wall for turbulent shear flows

1975 ◽  
Vol 70 (1) ◽  
pp. 149-160 ◽  
Author(s):  
B. Van Den Berg
Keyword(s):  
Experimental Data ◽  
Pressure Gradient ◽  
Velocity Vector ◽  
Shear Flows ◽  
Three Dimensional ◽  
Turbulent Shear ◽  
Inertial Forces ◽  
Flow Angle ◽  
Law Of The Wall ◽  
Good Agreement

An extended law of the wall is derived for three-dimensional flows. It describes the variation of the magnitude and direction of velocity close to the wall. The effects of both the pressure gradient and the inertial forces have been taken into account. The derived wall law is valid only when the deviations from the simple law of the wall are not large. The most important feature of a three-dimensional wall law is the prediction of the rotation of the velocity vector near the wall. Comparison of the flow angle variations predicted by the present wall law with the few available experimental data shows good agreement.

A Linearized Turbulent Lubrication Theory

1965 ◽  
Vol 87 (3) ◽  
pp. 675-682 ◽  
Author(s):  
Chung-Wah Ng ◽  
C. H. T. Pan
Keyword(s):  
Differential Equation ◽  
Experimental Data ◽  
Eddy Viscosity ◽  
Shear Flows ◽  
Momentum Transport ◽  
Turbulent Shear ◽  
New Approach ◽  
Turbulent Shear Flows ◽  
Governing Differential Equation ◽  
Turbulent Momentum

The “law of wall” for turbulent shear flows has been adapted to analyze turbulent lubrication. This new approach takes into account many well-established facts concerning turbulent shear flows. Isotropy of turbulent momentum transport (eddy viscosity) is assumed in treating nonplanar mean flows. A linearized version of the governing differential equation is established. Sample results agree well with available experimental data.

Scaling laws for fully developed turbulent shear flows. Part 2. Processing of experimental data

1993 ◽  
Vol 248 ◽  
pp. 521-529 ◽  
Author(s):  
G. I. Barenblatt ◽  
V. M. Prostokishin
Keyword(s):  
Experimental Data ◽  
Velocity Distribution ◽  
Skin Friction ◽  
Scaling Laws ◽  
Shear Flows ◽  
Scaling Law ◽  
Turbulent Shear ◽  
Main Body ◽  
Turbulent Shear Flows ◽  
Logarithmic Law

In Part 1 of this work (Barenblatt 1993) a non-universal scaling law (depending on the Reynolds number) for the mean velocity distribution in fully developed turbulent shear flow was proposed, together with the corresponding skin friction law. The universal logarithmic law was also discussed and it was shown that it can be understood, in fact, as an asymptotic branch of the envelope of the curves corresponding to the scaling law.Here in Part 2 the comparisons with experimental data are presented in detail. The whole set of classic Nikuradze (1932) data, concerning both velocity distribution and skin friction, was chosen for comparison. The instructive coincidence of predictions with experimental data suggests the conclusion that the influence of molecular viscosity within the main body of fully developed turbulent shear flows remains essential, even at very large Reynolds numbers. Meanwhile, some incompleteness of the experimental data presented in the work of Nikuradze (1932) is noticed, namely the lack of data in the range of parameters where the difference between scaling law and universal logarithmic law predictions should be the largest.

Numerical Study of Turbulent Helical Pipe Flow With Comparison to the Experimental Results

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Anup Kumer Datta ◽  
Yasutaka Hayamizu ◽  
Toshinori Kouchi ◽  
Yasunori Nagata ◽  
Kyoji Yamamoto ◽  
...  
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Secondary Flow ◽  
Pipe Flow ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Turbulence Models ◽  
Experimental Results ◽  
Helical Pipe ◽  
Wide Range

Turbulent flow through helical pipes with circular cross section is numerically investigated comparing with the experimental results obtained by our team. Numerical calculations are carried out for two helical circular pipes having different pitches and the same nondimensional curvature δ (=0.1) over a wide range of the Reynolds number from 3000 to 21,000 for torsion parameter β (=torsion /2δ  = 0.02 and 0.45). We numerically obtained the secondary flow, the axial flow and the intensity of the turbulent kinetic energy by use of three turbulence models incorporated in OpenFOAM. We found that the change to fully developed turbulence is identified by comparing experimental data with the results of numerical simulations using turbulence models. We also found that renormalization group (RNG) k−ε turbulence model can predict excellently the fully developed turbulent flow with comparison to the experimental data. It is found that the momentum transfer due to turbulence dominates the secondary flow pattern of the turbulent helical pipe flow. It is interesting that torsion effect is more remarkable for turbulent flows than laminar flows.

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