How important are direct interactions between large and small scales in turbulent flows?

Tsinober, A.

doi:10.1007/978-3-0348-8585-0_10

Cited by 8 publications

(4 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is different from the original assumption by Tennekes 11 ͑and similar͒ that the microstructure is statistically independent of the energy containing eddies. There is a growing body of experimental evidence 10,19,[22][23][24]30 suggesting that large and small scales are not statistically independent despite being practically decorrelated. This issue, however, is beyond the scope of this article.…”

Section: Summary and Discussionmentioning

confidence: 99%

“…A survey of data in the literature 10,13,17,19,22,23 suggests that the random Taylor hypothesis is qualitatively correct but also subject to a number of quantitative deviations. However, because of the Reynolds number limitations on previous data ͑especially earlier work 17 in DNS͒, it is important to understand in detail and quantify the Reynolds number dependence of the various statistical parameters involved.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Random Taylor hypothesis and the behavior of local and convective accelerations in isotropic turbulence

2001

Self Cite

View full text Add to dashboard Cite

The properties of acceleration fluctuations in isotropic turbulence are studied in direct numerical simulations ͑DNS͒ by decomposing the acceleration as the sum of local and convective contributions ͑a L ϭ‫ץ‬u/‫ץ‬t and a C ϭu•ٌu͒, or alternatively as the sum of irrotational and solenoidal contributions ͓a I ϭϪٌ( p/) and a S ϭٌ 2 u͔. The main emphasis is on the nature of the mutual cancellation between a L and a C which must occur in order for the acceleration ͑a͒ to be small as predicted by the ''random Taylor hypothesis'' ͓Tennekes, J. Fluid Mech. 67, 561 ͑1975͔͒ of small eddies in turbulent flow being passively ''swept'' past a stationary Eulerian observer. Results at Taylor-scale Reynolds number up to 240 show that the random-Taylor scenario ͗a 2 ͘Ӷ͗a C 2 ͘ Ϸ͗a L 2 ͘, accompanied by strong antialignment between the vectors a L and a C , is indeed increasingly valid at higher Reynolds number. Mutual cancellation between a L and a C also leads to the solenoidal part of a being small compared to its irrotational part. Results for spectra in wave number space indicate that, at a given Reynolds number, the random Taylor hypothesis has greater validity at decreasing scale sizes. Finally, comparisons with DNS data in Gaussian random fields show that the mutual cancellation between a L and a C is essentially a kinematic effect, although the Reynolds number trends are made stronger by the dynamics implied in the Navier-Stokes equations.

show abstract

Section: Summary and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Random Taylor hypothesis and the behavior of local and convective accelerations in isotropic turbulence

2001

Self Cite

View full text Add to dashboard Cite

show abstract

“…The coupling between large and small scales plays a central role in turbulent shear flows and is manifested at the lowest level via building up of gradients of mean Reynolds stresses, which appear in the Reynolds equations, rather than Reynolds stresses themselves [ 33]. This is seen from the identity…”

Section: Appendix a A Check Of Statistical Coupling Between Large And...mentioning

confidence: 99%

“…Note that the above check is extremely useful in testing the performance of multihotwire probes when attempting to measure velocity gradients [33] in turbulent shear flows.…”

Section: Appendix a A Check Of Statistical Coupling Between Large And...mentioning

confidence: 99%

On alignments and small scale structure in turbulent pipe flow

1995

View full text Add to dashboard Cite

The data base of an extensive DNS of turbulent flow in a pipe (Eggels et al. J. Fluid Mech. 268 (1994) 175) at Re = 7000, based on the pipe diameter and the centerline velocity or Ref = 360 based on the friction velocity u~, has been used to study some of the alignments discovered recently in quasi-isotropic and shear turbulent flows and attracted considerable attention. These are the alignments between the velocity u and vorticity vectors to, between the vorticity to and the eigenvectors of the rate of strain tensor sij, and between to and the vortex stretching vector Wi = toj sij. Comparison of these alignments strongly indicates that the quasi-two-dimensional (QTD) state of turbulent pipe flow in regions of strong alignment between to and the intermediate eigenvector ,~int of the rate of strain tensor sij is qualitatevly different from purely two-dimensional one. This is manifested in stronger alignments between to and W in these regions as well as in larger enstrophy generation ((.OiWjSij) =-(o)iWi) and large (W2), which are identically zero for a purely two-dimensional flow.The same is true of regions with concentrated vorticity, most of which are embedded into the regions with strong alignment between to and ~[int.

show abstract

Bibliography

2004

Fluid Mechanics and Its Applications

View full text Add to dashboard Cite

How important are direct interactions between large and small scales in turbulent flows?

Cited by 8 publications

References 47 publications

Random Taylor hypothesis and the behavior of local and convective accelerations in isotropic turbulence

Random Taylor hypothesis and the behavior of local and convective accelerations in isotropic turbulence

On alignments and small scale structure in turbulent pipe flow

Bibliography

Contact Info

Product

Resources

About