Direct numerical simulation of a 30R long turbulent pipe flow at R+ = 685: large- and very large-scale motions

2012 ◽  
Vol 698 ◽  
pp. 235-281 ◽  
Author(s):  
Xiaohua Wu ◽  
J. R. Baltzer ◽  
R. J. Adrian
Keyword(s):  
Spatial Data ◽  
Pipe Flow ◽  
Large Scale ◽  
Single Point ◽  
Complex Structure ◽  
Turbulent Pipe Flow ◽  
Bulk Velocity ◽  
Experimental Measurements ◽  
Flow Profile ◽  
Taylor’S Hypothesis

AbstractFully developed incompressible turbulent pipe flow at Reynolds number ${\mathit{Re}}_{D} = 24\hspace{0.167em} 580$ (based on bulk velocity) and Kármán number ${R}^{+ } = 684. 8$ is simulated in a periodic domain with a length of $30$ pipe radii $R$. While single-point statistics match closely with experimental measurements, questions have been raised of whether streamwise energy spectra calculated from spatial data agree with the well-known bimodal spectrum shape in premultiplied spectra produced by experiments using Taylor’s hypothesis. The simulation supports the importance of large- and very large-scale motions (VLSMs, with streamwise wavelengths exceeding $3R$). Wavenumber spectral analysis shows evidence of a weak peak or flat region associated with VLSMs, independent of Taylor’s hypothesis, and comparisons with experimental spectra are consistent with recent findings (del Álamo & Jiménez, J. Fluid Mech., vol. 640, 2009, pp. 5–26) that the long-wavelength streamwise velocity energy peak is overestimated when Taylor’s hypothesis is used. Yet, the spectrum behaviour retains otherwise similar properties to those documented based on experiment. The spectra also reveal the importance of motions of long streamwise length to the $uu$ energy and $uv$ Reynolds stress and support the general conclusions regarding these quantities formed using experimental measurements. Space–time correlations demonstrate that low-level correlations involving very large scales persist over $40R/ {U}_{\mathit{bulk}} $ in time and indicate that these motions convect at approximately the bulk velocity, including within the region approaching the wall. These very large streamwise motions are also observed to accelerate the flow near the wall based on force spectra, whereas smaller scales tend to decelerate the mean streamwise flow profile, in accordance with the behaviour observed in net force spectra of prior experiments. Net force spectra are resolved for the first time in the buffer layer and reveal an unexpectedly complex structure.

scholarly journals The evolution of large-scale motions in turbulent pipe flow

2015 ◽  
Vol 779 ◽  
pp. 701-715 ◽  
Author(s):  
Leo H. O. Hellström ◽  
Bharathram Ganapathisubramani ◽  
Alexander J. Smits
Keyword(s):  
Pipe Flow ◽  
Large Scale ◽  
Complex Structure ◽  
Turbulent Pipe Flow ◽  
Large Scale Structures ◽  
Large Structures ◽  
Scale Structures ◽  
The Cross ◽  
Spatio Temporal ◽  
Temporal Extent

A dual-plane snapshot proper orthogonal decomposition (POD) analysis of turbulent pipe flow at a Reynolds number of 104 000 is presented. The high-speed particle image velocimetry data were simultaneously acquired in two planes, a cross-stream plane (2D–3C) and a streamwise plane (2D–2C) on the pipe centreline. The cross-stream plane analysis revealed large structures with a spatio-temporal extent of $1{-}2R$, where $R$ is the pipe radius. The temporal evolution of these large-scale structures is examined using the time-shifted correlation of the cross-stream snapshot POD coefficients, identifying the low-energy intermediate modes responsible for the transition between the large-scale modes. By conditionally averaging based on the occurrence/intensity of a given cross-stream snapshot POD mode, a complex structure consisting of wall-attached and -detached large-scale structures is shown to be associated with the most energetic modes. There is a pseudo-alignment of these large structures, which together create structures with a spatio-temporal extent of approximately $6R$, which appears to explain the formation of the very-large-scale motions previously observed in pipe flow.

A direct numerical simulation study on the mean velocity characteristics in turbulent pipe flow

2008 ◽  
Vol 608 ◽  
pp. 81-112 ◽  
Author(s):  
XIAOHUA WU ◽  
PARVIZ MOIN
Keyword(s):  
Reynolds Number ◽  
Pipe Flow ◽  
Large Scale ◽  
Turbulent Pipe Flow ◽  
Bulk Velocity ◽  
Mean Velocity ◽  
Large Scale Structures ◽  
Narrow Region ◽  
The Mean ◽  
Scale Structures

Fully developed incompressible turbulent pipe flow at bulk-velocity- and pipe-diameter-based Reynolds number ReD=44000 was simulated with second-order finite-difference methods on 630 million grid points. The corresponding Kármán number R+, based on pipe radius R, is 1142, and the computational domain length is 15R. The computed mean flow statistics agree well with Princeton Superpipe data at ReD=41727 and at ReD=74000. Second-order turbulence statistics show good agreement with experimental data at ReD=38000. Near the wall the gradient of $\mbox{ln}\overline{u}_{z}^{+}$ with respect to ln(1−r)+ varies with radius except for a narrow region, 70 < (1−r)+ < 120, within which the gradient is approximately 0.149. The gradient of $\overline{u}_{z}^{+}$ with respect to ln{(1−r)++a+} at the present relatively low Reynolds number of ReD=44000 is not consistent with the proposition that the mean axial velocity $\overline{u}_{z}^{+}$ is logarithmic with respect to the sum of the wall distance (1−r)+ and an additive constant a+ within a mesolayer below 300 wall units. For the standard case of a+=0 within the narrow region from (1−r)+=50 to 90, the gradient of $\overline{u}_{z}^{+}$ with respect to ln{(1−r)++a+} is approximately 2.35. Computational results at the lower Reynolds number ReD=5300 also agree well with existing data. The gradient of $\overline{u}_{z}$ with respect to 1−r at ReD=44000 is approximately equal to that at ReD=5300 for the region of 1−r > 0.4. For 5300 < ReD < 44000, bulk-velocity-normalized mean velocity defect profiles from the present DNS and from previous experiments collapse within the same radial range of 1−r > 0.4. A rationale based on the curvature of mean velocity gradient profile is proposed to understand the perplexing existence of logarithmic mean velocity profile in very-low-Reynolds-number pipe flows. Beyond ReD=44000, axial turbulence intensity varies linearly with radius within the range of 0.15 < 1−r < 0.7. Flow visualizations and two-point correlations reveal large-scale structures with comparable near-wall azimuthal dimensions at ReD=44000 and 5300 when measured in wall units. When normalized in outer units, streamwise coherence and azimuthal dimension of the large-scale structures in the pipe core away from the wall are also comparable at these two Reynolds numbers.

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’.

Pipe Flow Measurements of a Transparent Non-Newtonian Slurry

1989 ◽  
Vol 111 (3) ◽  
pp. 331-336 ◽  
Author(s):  
J. T. Park ◽  
R. J. Mannheimer ◽  
T. A. Grimley ◽  
T. B. Morrow
Keyword(s):  
Velocity Profile ◽  
Newtonian Fluid ◽  
Power Law ◽  
Pipe Flow ◽  
Large Scale ◽  
Longitudinal Velocity ◽  
Tangential Velocity ◽  
Turbulent Pipe Flow ◽  
Laser Doppler Velocimeter ◽  
Flow Measurements

An experimental description of the flow structure of non-Newtonian slurries in the laminar, transitional, and full turbulent pipe flow regimes is the primary objective of this research. Experiments were conducted in a large-scale pipe slurry flow facility with an inside pipe diameter of 51 mm. The transparent slurry formulated for these experiments from silica, mineral oil, and Stoddard solvent exhibited a yield-power-law behavior from concentric-cylinder viscometer measurements. The velocity profile for laminar flow from laser Doppler velocimeter (LDV) measurements had a central plug flow region, and it was in agreement with theory. The range of the transition region was narrower than that for a Newtonian fluid. The mean velocity profile for turbulent flow was close to a 1/7 power-law velocity profile. The rms longitudinal velocity profile was also similar to a classical turbulent pipe flow experiment for a Newtonian fluid; however, the rms tangential velocity profile was significantly different.

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.

Spectral Analysis of Large Scale Structures in Fully Developed Turbulent Pipe Flow

PAMM ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 647-650
Author(s):  
El-Sayed Zanoun ◽  
Emir Öngüner ◽  
Amir Shahirpour ◽  
Sebastian Merbold ◽  
Christoph Egbers
Keyword(s):  
Spectral Analysis ◽  
Pipe Flow ◽  
Large Scale ◽  
Turbulent Pipe Flow ◽  
Large Scale Structures ◽  
Scale Structures

Pulsating pipe flow with large-amplitude oscillations in the very high frequency regime. Part 1. Time-averaged analysis

2012 ◽  
Vol 700 ◽  
pp. 246-282 ◽  
Author(s):  
M. Manna ◽  
A. Vacca ◽  
R. Verzicco
Keyword(s):  
Pipe Flow ◽  
Oscillatory Flow ◽  
Turbulent Pipe Flow ◽  
Bulk Velocity ◽  
Subsequent Paper ◽  
Very High Frequency ◽  
Harmonic Forcing ◽  
Frequency Regime ◽  
Pipe Radius ◽  
The Mean

AbstractThis paper numerically investigates the effects of a harmonic volume forcing of prescribed frequency on the turbulent pipe flow at a Reynolds number, based on bulk velocity and pipe diameter, of 5900. The thickness of the Stokes layer, resulting from the oscillatory flow component, is a small fraction of the pipe radius and therefore the associated vorticity is confined within a few wall units. The harmonic forcing term is prescribed so that the ratio of the oscillating to the mean bulk velocity ($\ensuremath{\beta} $) ranges between 1 and 10.6. In all cases the oscillatory flow obeys the Stokes analytical velocity distribution while remarkable changes in the current component are observed. At intermediate values $\ensuremath{\beta} = 5$, a relaminarization process occurs, while for $\ensuremath{\beta} = 10. 6$, turbulence is affected so much by the harmonic forcing that the near-wall coherent structures, although not fully suppressed, are substantially weakened. The present study focuses on the analysis of the time- and space-averaged statistics of the first- and second-order moments, vorticity fluctuations and Reynolds stress budgets. Since the flow is unsteady not only locally but also in its space-averaged dynamics, it can be analysed using phase-averaged and time-averaged statistics. While the former gives information about the statistics of the fluctuations about the mean, the latter, postponed to a subsequent paper, shows how the mean is affected by the fluctuations. Clearly, the two phenomena are connected and both of them deserve investigation.

Large-scale and very-large-scale motions in turbulent pipe flow

2006 ◽  
Vol 554 (-1) ◽  
pp. 521 ◽  
Author(s):  
M. GUALA ◽  
S. E. HOMMEMA ◽  
R. J. ADRIAN
Keyword(s):  
Pipe Flow ◽  
Large Scale ◽  
Turbulent Pipe Flow
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