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

Ramaprian, B. R.; Tu, S. W.

doi:10.1017/s0022112083002293

Cited by 101 publications

(38 citation statements)

References 11 publications

(13 reference statements)

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“…Both cases show that the turbulence intensity maintains the same phase lag relative to the velocity. This observation is in excellent agreement with results shown by Ramaprian and Tu, 20 but one should notice that their results concerned the centerline fluctuations only. Akhavan et al 38 report the turbulent kinetic energy integrated over the cross section, but these results are opposite to the results shown here.…”

Section: -12supporting

confidence: 92%

An experimental study of transitional pulsatile pipe flow

et al. 2012

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The transitional regime of a sinusoidal pulsatile flow in a straight, rigid pipe is investigated using particle image velocimetry. The main aim is to investigate how the critical Reynolds number is affected by different pulsatile conditions, expressed as the Womersley number and the oscillatory Reynolds number. The transition occurs in the region of Re ¼ 2250-3000 and is characterized by an increasing number of isolated turbulence structures. Based on velocity fields and flow visualizations, these structures can be identified as puffs, similar to those observed in steady flow transition. Measurements at different Womersley numbers yield similar transition behavior, indicating that pulsatile effects do not play a role in the regime that is investigated. Variations of the oscillatory Reynolds number also appear to have little effect, so that the transition here seems to be determined only by the mean Reynolds number. For larger mean Reynolds numbers, a second regime is observed: here, the flow remains turbulent throughout the cycle. The turbulence intensity varies during the cycle, but has a phase shift with respect to the mean flow component. This is caused by a growth of kinetic energy during the decelerating part and a decay during the accelerating part of the cycle. Flow visualization experiments reveal that the flow develops localized turbulence at several random axial positions. The structures quickly grow to fill the entire pipe in the decelerating phase and (partially) decay during the accelerating phase.

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Section: -12supporting

confidence: 92%

An experimental study of transitional pulsatile pipe flow

et al. 2012

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“…Ramaprian and Tu (1983) found that for sufficiently high frequencies, the time-averaged flow variables, e.g., velocity, wall shear stresses, and power loss due to friction, were affected by the imposed unsteadiness. They also concluded that, from their computations, a quasi-steady turbulence model cannot adequately describe unsteady flow conditions, at least for high frequencies.…”

Section: Introductionmentioning

confidence: 97%

“…The problems of periodic turbulent internal flow have been studied by many research workers experimentally as well as computationally (Hershey and Im 1968;Hino et al 1983;Hino et al 1976;Mizushina et al 1975;Ohmi et al 1982aOhmi et al , 1982bRamaprian and Tu 1983;Sarpkaya 1966). The periodic flow can be divided into two classes: (1) unsteady flow with nonzero mean velocity and (2) unsteady flow with zero mean velocity.…”

Section: Introductionmentioning

confidence: 99%

Laminar/turbulent oscillating flow in circular pipes

Ahn

Ibrahim

1992

International Journal of Heat and Fluid Flow

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A two-dimensional oscillating flow analysis was conducted simulating the gas flow inside Stirling engine heat exchangers. Both laminar and turbulent oscillating pipe flow were investigated numerically for Remax=l,920 (Va=80), 10,800 (Va=272), 19,300 (Va = 272), and 60,800 (Va = 126). The results are here compared with experimental results of previous investigators. Predictions of the flow regime on present oscillating flow conditions are also checked by comparing velocity amplitudes and phase difference with those from laminar theory and quasi-steady profile. A high Reynolds number k-e turbulence model was used for turbulent oscillating pipe flow. Finally, the performance of the k-e model was evaluated to explore the applicability of quasi-steady turbulent models to unsteady oscillating flow analysis.

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“…Many experimental and numerical studies of unsteady turbulent pipe (Mizushina et al, 1973;Ramaprian and Tu, 1983;Shemer et al, 1985) and channel (Tardu et al, 1994;Piomelli, 2001, 2002) flows have focused on periodic pulsating flows rather than non-periodic transient ones due to their practical applications concerned and the easy generation of the periodic flows. Mizushina et al (1973), Ramaprian and Tu (1983), Shemer et al (1985), and Tardu et al (1994) have found that, in pulsating turbulent flow experiments, the effects of the pulsation frequency and the mean flow rate were significant to the turbulence whereas that of amplitude was small.…”

Section: Introductionmentioning

confidence: 99%

“…Mizushina et al (1973), Ramaprian and Tu (1983), Shemer et al (1985), and Tardu et al (1994) have found that, in pulsating turbulent flow experiments, the effects of the pulsation frequency and the mean flow rate were significant to the turbulence whereas that of amplitude was small. Piomelli (2001, 2002) performed a large-eddy simulations (LES) of pulsating channel flow and subsequently tested the capability of Reynolds-avegared Navier-Stokes (RANS) equations simulations.…”

Section: Introductionmentioning

confidence: 99%

Large-eddy simulation of accelerated turbulent flow in a circular pipe

Jung

Chung

2012

International Journal of Heat and Fluid Flow

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Turbulent pipe flows subject to temporal acceleration have been considered in this study.Large-eddy simulations (LESs) of accelerated turbulent flow in a circular pipe were performed to study the response of the turbulent flow to temporal acceleration. The simulations were started with the fully-developed turbulent pipe flow at an initial Re number, and then a constant temporal acceleration was applied. During the acceleration, the Reynolds number of the pipe flow, based on the pipe diameter and the bulk-mean velocity, increased linearly from Re D = 7000 to 36000. A dimensionless response time for various flow quantities was introduced to measure the delays in the response of the near-wall turbulence to temporal acceleration. The results reveal distinctive features of the delays responsible for turbulence production, energy redistribution, and radial propagation. The conditionally-averaged flow fields associated with Reynolds shear stress producing events were analysed. In the transient flows, sweeps and ejections were closely linked to the delays of turbulence production and of turbulence propagation away from * Corresponding author: Y.M.Chung@warwick.ac.uk the wall. It is found that strong sweep events were related to the delayed turbulence production in the near-wall region, while ejection events were associated with the propagation of the turbulence away from the wall. The results show that the anisotropy of the turbulence was enhanced during the transient, and this would be a challenging problem to standard turbulence models.

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

Cited by 101 publications

References 11 publications

An experimental study of transitional pulsatile pipe flow

An experimental study of transitional pulsatile pipe flow

Laminar/turbulent oscillating flow in circular pipes

Large-eddy simulation of accelerated turbulent flow in a circular pipe

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