Initial relaxation of spatially evolving turbulent channel flow with blowing and suction

Chung, Yongmann M.; Sung, Hyung Jin

doi:10.2514/3.14973

Cited by 6 publications

(16 citation statements)

References 15 publications

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“…Note u τ decreases by 15% when blowing is applied and increases by 20% at the suction wall. 6 The changes in u τ due to blowing and suction are in good agreement with those found in the temporal DNS. 5 Consequently, ω + x increases by 90% with blowing and decreases by 67% with suction.…”

Section: Resultssupporting

confidence: 77%

“…The elongation of the low-speed streaks and the suppression of the spanwise meandering motion of the streaks were also observed in recent DNS study. 6,17 These findings imply that the anisotropy of the near-wall region can be significantly affected by the application of wall blowing and suction.…”

mentioning

confidence: 82%

“…In the DNS 6 that provides the data set employed in this analysis, the code developed by Yang and Ferziger 20 is used. Here, we only summarize the numerical method briefly.…”

Section: Dns Methodsmentioning

confidence: 99%

“…The anisotropy of a turbulent boundary layer with uniform suction was investigated by Antonia et al 19 by analyzing a DNS of Mariani et al 4 They 19 found that the anisotropy increased significantly near the wall region when suction was applied at the wall. On the other hand, the effects of wall blowing on turbulence anisotropy is not conclusive, 13 although some experimental 15 and numerical 5,6 studies suggest that wall blowing makes the flow more isotropic.…”

mentioning

confidence: 99%

“…The databases used in the present study are obtained from DNS of a spatially developing turbulent channel flow. 6 A fully developed turbulent channel flow is subjected to sudden wall blowing and suction after an entrance section (Fig. 1).…”

mentioning

confidence: 99%

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Modulation of Near-Wall Turbulence Structure with Wall Blowing and Suction

2002

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The effects of wall blowing and suction on a fully developed, equilibrium turbulent channel flow are studied numerically. Direct numerical simulation data are analyzed to investigate the modulation of near-wall turbulence anisotropy after the sudden application of wall blowing and suction. The effects on the near-wall turbulence structure are examined in terms of the asymptotic near-wall behavior of various turbulence quantities and the turbulence anisotropy. It is found that blowing makes the near-wall flow more isotropic and enhances the transverse (v and w ) components of velocity fluctuations. A significant increase in the anisotropy of the near-wall region is found in the suction case. The anisotropy invariant map for the Reynolds stress anisotropy tensor indicates that the relaxation processes of the anisotropy of the near-wall turbulence are different for the blowing and suction cases, respectively. The response of the flow to the sudden application of wall blowing and suction occurs earlier for blowing than for suction, although there is a delayed response in both cases. Nomenclature b i j= Reynolds stress anisotropy tensor,

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Section: Resultssupporting

confidence: 77%

mentioning

confidence: 82%

“…In the DNS 6 that provides the data set employed in this analysis, the code developed by Yang and Ferziger 20 is used. Here, we only summarize the numerical method briefly.…”

Section: Dns Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Modulation of Near-Wall Turbulence Structure with Wall Blowing and Suction

2002

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Unsteady turbulent flow with sudden pressure gradient changes

Chung

2005

Numerical Methods in Fluids

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Direct numerical simulations are performed for a turbulent flow subjected to a sudden change in pressure gradient. The calculations are started from a fully-developed turbulent channel flow at. The pressure gradient of the channel flow is then changed abruptly. The responses of the turbulence quantities (e.g., turbulence intensities, Reynolds shear stress, and vorticity fluctuations) and the near-wall turbulence structure to the pressure gradient change are investigated. It is found that there are two different relaxations: a fast relaxation at the early stage and a slow one at the later stage. The early response of the velocity fluctuations shows an anisotropic response of the near-wall turbulence.

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New scaling laws for turbulent Poiseuille flow with wall transpiration

2014

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Under consideration for publication in J. Fluid Mech. 1 New Scaling Laws for Turbulent PoiseuilleFlow with Wall Transpiration A fully developed, turbulent Poiseuille flow with wall transpiration, i.e. uniform blowing and suction on the lower and upper walls correspondingly, is investigated by both direct numerical simulation (DNS) of the three-dimensional, incompressible Navier-Stokes equations and Lie symmetry analysis. The latter is used to find symmetry transformations and in turn to derive invariant solutions of the set of two-and multi-point correlation equations. We show that the transpiration velocity is a symmetry breaking which implies a logarithmic scaling law in the core of the channel. DNS validates this result of Lie symmetry analysis and hence aids establishing a new logarithmic law of deficit-type. The region of validity of the new logarithmic law is very different from the usual near-wall log-law and the slope constant in the core region differs from the von Kármán constant and is equal to 0.3. Further, extended forms of the linear viscous sublayer law and the near-wall log-law are also derived, which, as a particular case, include these laws for the classical non-transpirating case. The viscous sublayer at the suction side has an asymptotic suction profile. The thickness of the sublayer increase at high Reynolds and transpiration numbers. For the near-wall log-law we see an indication that it appears at the moderate transpiration rates (0.05 < v 0 /u τ < 0.1) and only at the blowing wall. Finally, from the DNS data we establish a relation between the friction velocity u τ and the transpiration v 0 which turns out to be linear at moderate transpiration rates.

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Initial relaxation of spatially evolving turbulent channel flow with blowing and suction

Cited by 6 publications

References 15 publications

Modulation of Near-Wall Turbulence Structure with Wall Blowing and Suction

Modulation of Near-Wall Turbulence Structure with Wall Blowing and Suction

Unsteady turbulent flow with sudden pressure gradient changes

New scaling laws for turbulent Poiseuille flow with wall transpiration

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