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Large-scale turbulent structure of uniform shallow free-surface flows

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Abstract

The hydrodynamics of super- and sub-critical shallow uniform free-surface flows are assessed using laboratory experiments aimed at identifying and quantifying flow structure at scales larger than the flow depth. In particular, we provide information on probability distributions of horizontal velocity components, their correlation functions, velocity spectra, and structure functions for the near-water-surface flow region. The data suggest that for the high Froude number flows the structure of the near-surface layer resembles that of two-dimensional turbulence with an inverse energy cascade. In contrast, although large-scale velocity fluctuations were also present in low Froude number flow its behaviour was different, with a direct energy cascade. Based on our results and some published data we suggest a physical explanation for the observed behaviours. The experiments support Jirka’s [Jirka GH (2001) J Hydraul Res 39(6):567–573] hypothesis that secondary instabilities of the base flow may generate large-scale two-dimensional eddies, even in the absence of transverse gradients in the time-averaged flow properties.

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Abbreviations

PTV:

Particle Tracking Velocimetry

CCD:

Charge-coupled device

PULNiXTM :

TM-6710 progressive scan digital camera

g :

Gravity acceleration

H :

Flow depth

S :

Bed slope

u :

Longitudinal velocity component

u * :

Shear velocity, u * = (τ o /ρ)0.5 = (gHS)0.5

U a :

Vertically-averaged longitudinal velocity

U s :

Spatially- and time-averaged near-surface longitudinal velocity

v :

Transverse velocity component

ρ:

Fluid density

τ o :

Bed shear stress

Fr :

Froude number, Fr = U a /(gH)0.5

Re :

Reynolds number, Re = U a H

f :

Friction factor, f = 8(u * /U a )2

References

  1. Jirka GH (2001) Large-scale flow structures and mixing processes in shallow flows. J Hydraul Res 39(6):567–573

    Article  Google Scholar 

  2. Nezu I, Nakagawa, H (1993) Turbulence in open-channel flows. A.A. Balkema, Rotterdam, Brookfield, the Netherlands

  3. Carrasco A, Vionnet CA (2004) Separation of scales on a broad shallow turbulent flow. J Hydraul Res 42(6):630–638

    Article  Google Scholar 

  4. Uijttewaal WSJ, Jirka GH (2003) Grid turbulence in shallow flows. J Fluid Mech 489:325–344

    Article  Google Scholar 

  5. Yokosi S (1967) The structure of river turbulence. Bull Disaster Prev Res Inst Kyoto Univ 17(2): #121:1–29

    Google Scholar 

  6. Grinvald D, Nikora V (1988) River turbulence (in Russian). Hydrometeoizdat, Leningrad, Russia

    Google Scholar 

  7. Nikora V (1991) A physical model of fluvial turbulence. In: Refined flows, modelling. Proc. XXIV Congress IAHR, Madrid (Espana), pp C-549–C-556

  8. Tamburino A, Gulliver JS (1999) Large flow structures in a turbulent open channel flow. J Hydraul Res 37(3):363–380

    Article  Google Scholar 

  9. Chu VH, Babarutsi S (1988) Confinement and bed friction effects in shallow turbulent mixing layers. J Hydraul Engng 114:1257–1274

    Article  Google Scholar 

  10. Kumar S, Gupta R, Banerjee S (1998) An experimental investigation of the characteristics of free-surface turbulence in channel flow. Phys Fluids 10(2):437–456

    Article  CAS  Google Scholar 

  11. Weitbrecht V, Kuhn G, Jirka GH (2002) Large-scale PIV-measurements at the surface of shallow water flows. Flow Meas Instrum 13:237–245

    Article  Google Scholar 

  12. Nokes R (2005) FluidStream, version 6.01: system theory and design. Department of Civil Engineering, University of Canterbury, New Zealand

  13. Nokes R (2005) FluidStream, version 6.01: user’s guide. Department of Civil Engineering, University of Canterbury, New Zealand

  14. Pan Y, Banerjee S (1995) A numerical study of free-surface turbulence in channel flow. Phys Fluids 7(7):1649–1664

    Article  CAS  Google Scholar 

  15. Veale WB (2005) Shallow flow turbulence: an experimental study, Thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering, University of Canterbury, Christchurch, New Zealand, pp 139

  16. Danilov SD, Gurarie D (2000) Quasi-two-dimensional turbulence. Phys Uspekhi 43(9):863–900

    Article  CAS  Google Scholar 

  17. Pasquero C, Provenzale A, Babiano A (2001) Parameterization of dispersion in two-dimensional turbulence. J Fluid Mech 439:279–303

    Article  CAS  Google Scholar 

  18. Tabeling P (2002) Two-dimensional turbulence: a physicist approach. Phys Reports 362:1–62

    Article  Google Scholar 

  19. Nikora VI (1999) Origin of the “−1” spectral law in wall-bounded turbulence. Phys Rev Lett 83:734–737

    Article  CAS  Google Scholar 

  20. Nikora V, Goring D (2000) Flow turbulence over fixed and weakly mobile gravel beds. J Hydraul Eng ASCE 126(9):679–690

    Article  Google Scholar 

  21. Nikora V, Goring D (2000) Eddy convection velocity and Taylor’s hypothesis of ’frozen’ turbulence in a rough-bed open-channel flow. J Hydrosci Hydraul Eng JSCE 18(2):75–91

    Google Scholar 

  22. Frisch U (1995) Turbulence. The Legacy of A. N. Kolmogorov. Cambridge University Press, Cambridge, England

    Google Scholar 

  23. Paret J, Tabeling T (1998) Intermittency in the two-dimensional inverse cascade of energy: experimental observations. Phys Fluids 10(12):3126–3326

    Article  CAS  Google Scholar 

  24. Belmonte A, Goldburg WI, Kellay H, Rutgers MA, Martin B, Wu XL (1999) Velocity fluctuations in a turbulent soap film: the third moment in two dimensions. Phys Fluids 11(5):1196–1200

    Article  CAS  Google Scholar 

  25. Shen L., Zhang X, Yue DKP, Triantafyllou GS (1999) The surface layer for free-surface turbulent flows. J Fluid Mech 386:167–221

    Article  CAS  Google Scholar 

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Nikora, V., Nokes, R., Veale, W. et al. Large-scale turbulent structure of uniform shallow free-surface flows. Environ Fluid Mech 7, 159–172 (2007). https://doi.org/10.1007/s10652-007-9021-z

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  • DOI: https://doi.org/10.1007/s10652-007-9021-z

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