Numerical simulation of pulsating turbulent channel flow

Scotti, Alberto; Piomelli, Ugo

doi:10.1063/1.1359766

Cited by 184 publications

(195 citation statements)

References 49 publications

Supporting

Mentioning

172

Contrasting

Unclassified

Order By: Relevance

“…The domain dimensions are set to l x ϫ l y ϫ h =4ϫ 2 ϫ 1, which is comparable to the one used by Scotti and Piomelli. 7 The largest correlation scale in the velocity field we observe in the simulations is about 0.3, i.e., much smaller than the horizontal domain dimensions.…”

Section: Numerical Setupmentioning

confidence: 99%

“…Several studies revealed that LES can be used for oscillating wall flows. 7,14 Nonetheless, we will also perform DNS for our specific flow problem, as in none of those studies a freesurface stress was applied in combination with an oscillatory forcing. In LES only the dynamics of the large scales in the flow are calculated directly.…”

Section: Numerical Setupmentioning

confidence: 99%

“…For an oscillating flow, it is important how deep the turbulence created in the shear layers near the wall can penetrate into the bulk of the flow. Scotti and Piomelli 7 performed turbulence simulations in a periodic channel domain driven by a pulsating pressure gradient. They introduced the turbulent Stokes length ␦ t = ͱ 2͑ + t ͒ / as a measure for the turbulent penetration depth, where t is an eddy viscosity.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Turbulent oscillating channel flow subjected to a free-surface stress

2010

View full text Add to dashboard Cite

The channel flow subjected to a wind stress at the free surface and an oscillating pressure gradient is investigated using large-eddy simulations. The orientation of the surface stress is parallel with the oscillating pressure gradient and a purely pulsating mean flow develops. The Reynolds number is typically Reω=106 and the Keulegan–Carpenter number—the ratio between the oscillation period and advection time scale—is KC=80. Results compare favorably to the data from direct numerical simulations obtained over a single period. A slowly pulsating mean flow occurs with the turbulent flow essentially being statistically steady. Logarithmic boundary layers are present at both the bottom wall and the free surface. Turbulent streaks are observed in the bottom and free-surface layer. The viscous sublayer below the free surface is, however, much thinner. This observation is verified by simulations we performed for a purely wind-driven channel flow. For the oscillating flow, additional low-speed splats (localized regions of upwelling) occur at the free surface when the mean velocity and stress are in the same direction.

show abstract

Section: Numerical Setupmentioning

confidence: 99%

Section: Numerical Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Turbulent oscillating channel flow subjected to a free-surface stress

2010

View full text Add to dashboard Cite

show abstract

“…The propagation starts at Re D = 21000 or ξ = 10, so the propagation velocity based on Re D = 21000 is about c + = 0.7. It is interesting to note that the new turbulence structures propagated at a constant speed in the acceleration phase of the pulsating turbulent channel flow (Scotti and Piomelli, 2001). At low pulsating frequencies, the propagation speed in the pulsating flow was c + = 2κ, where κ is the von Karman constant.…”

Section: Time Delaymentioning

confidence: 99%

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

Jung

Chung

2012

International Journal of Heat and Fluid Flow

View full text Add to dashboard Cite

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.

show abstract

“…There are extensive studies of periodic flows around a non-zero mean, and oscillatory flows around zero mean flows. Readers interested in those topics are referred to recent studies of Scotti & Piomelli (2001), Tardu & Da Costa (2005), He & Jackson (2009) and Manna, Vacca & Verzicco (2012) for pulsating flows and Fornarelli & Vittori (2009) and Van der A et al (2011) for oscillatory flows.…”

mentioning

confidence: 99%

Transition of transient channel flow after a change in Reynolds number

Seddighi

2015

J. Fluid Mech.

View full text Add to dashboard Cite

It has previously been shown that the transient flow in a channel following a step increase of Reynolds number from 2800 to 7400 (based on channel half-height and bulk velocity) is effectively a laminar-turbulent bypass transition even though the initial flow is turbulent (He & Seddighi, J. Fluid Mech., vol. 715, 2013, pp. 60-102). In this paper, it is shown that the transient flow structures exhibit strong contrasting characteristics in large and small flow perturbation scenarios. When the increase of Reynolds number is large, the flow is characterized by strong elongated streaks during the initial period, followed by the occurrence and spreading of isolated turbulent spots, as shown before. By contrast, the flow appears to evolve progressively and the turbulence regeneration process remains largely unchanged during the flow transient when the Reynolds number ratio is low, and streaks do not appear to play a significant role. Despite the major apparent differences in flow structures, the transient flow under all conditions considered is unambiguously characterized by laminar-turbulent transition, which exhibits itself clearly in various flow statistics. During the pre-transition period, the time-developing boundary layers in all the cases show a strong similarity to each other and follow closely the Stokes solution for a transient laminar boundary layer. The streamwise fluctuating velocity also shows good similarity in the various cases, irrespective of the appearance of elongated streaks or not, and the maximum energy growth exhibits a linear rate similar to that in a spatially developing boundary layer. The onset of transition is clearly definable in all cases using the minimum friction factor, and the critical time thus defined is strongly correlated with the free-stream turbulence in a power-law form.

show abstract

Numerical simulation of pulsating turbulent channel flow

Cited by 184 publications

References 49 publications

Turbulent oscillating channel flow subjected to a free-surface stress

Turbulent oscillating channel flow subjected to a free-surface stress

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

Transition of transient channel flow after a change in Reynolds number

Contact Info

Product

Resources

About