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  • Journal of Fluid Mechanics, Volume 593
  • December 2007, pp. 1-32

Shear instability and coherent structures in shallow flow adjacent to a porous layer

  • BRIAN L. WHITE (a1) and HEIDI M. NEPF (a2)
  • DOI:
  • Published online: 25 December 2007

Results are presented from an experimental study of shallow flow in a channel partially obstructed by an array of circular cylinders. The cylinder array is a model for emergent vegetation in an open channel, but also represents a simple sparse porous medium. A shear layer with regular vortex structures forms at the edge of the array, evolving downstream to an equilibrium width and vortex size. The vortices induce nearly periodic oscillations with a frequency that matches the most unstable linear mode for a parallel shear flow. The shear layer is asymmetric about the array interface and has a two-layer structure. An inner region of maximum shear near the interface contains a velocity inflection point and establishes the penetration of momentum into the array. An outer region, resembling a boundary layer, forms in the main channel, and establishes the scale of the vortices. The vortex structure, educed by conditional sampling, shows strong crossflows with sweeps from the main channel and ejections from the array, which create significant momentum and mass fluxes across the interface. The sweeps maintain the coherent structures by enhancing shear and energy production at the interface. A linear stability analysis is consistent with the experimental results and demonstrates that the instability is excited by the differential drag between the channel and the array.

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J. Bonnet , J. Delville , M. Glauser , R. Antnonia , D Bisset ., D. Cole , H. Fiedler , J. Garem , D. Hillberg , J. Jeong , N. Kevlahan , L. Ukeiley & E. Vincendeau 1998 Collaborative testing of eddy structure identification methods in free turbulent shear flows. Exps. Fluids 25, 197225.

D. Bousmar , N. Riviere , S. Proust , A. Paquier , R Morel . & Y. Zech 2005 Upstream discharge distribution in compound-channel flumes. J. Hydraul. Engng ASCE 131, 408412.

V. Chu , J.-H. Wu & R. Khayat 1991 Stability of transverse shear flows in shallow open channels. J. Hydraul. Engng ASCE 117, 13701388.

L. Djenidi , F. Anselmet & R. Antonia 1994 LDA measurements in a turbulent boundary layer over a d-type rough wall. Exps. Fluids 16, 323329.

J. Finnigan 2000 Turbulence in plant canopies. Annu. Rev. Fluid Mech. 32, 519571.

M. Ghidaoui & A. Kolyshkin 1999 Linear stability analysis of lateral motions in compound open channels. J. Hydraul. Engng ASCE 125, 871880.

M. Ghisalberti & H. M. Nepf 2002 Mixing layers and coherent structures in vegetated aquatic flows. J. Geophys. Res. Oceans 107 (C2), 3011.

C.-M. Ho & P. Huerre 1984 Perturbed free shear layers. Annu. Rev. Fluid Mech. 16, 365424.

A. Hussain 1983 Coherent structures – reality and myth. Phys. Fluids 26 (10), 28162850.

D. Koch & A. Ladd 1997 Moderate Reynolds number flows through periodic and random arrays of aligned cylinders. J. Fluid Mech. 349, 3166.

L. Leonard & M. Luther 1995 Flow hydrodynamics in tidal marsh canopies. Limnol. Oceanogr. 40, 14741484.

A. Lightbody & H. Nepf 2006 Prediction of near-field shear dispersion in an emergent canopy with heterogeneous morphology. Environ. Fluid Mech. 6, 477488.

P. Monkewitz & P. Huerre 1982 Influence of the velocity ratio on the spatial instability of mixing layers. Phys. Fluids 25, 11371143.

K. Nadaoka & H. Yagi 1998 Shallow-water turbulence modeling and horizontal large-eddy computation of river flow. J. Hydraul. Engng ASCE 124, 493500.

H. Nepf , M. Ghisalberti , B. White & E. Murphy 2007 Retention time and dispersion associated with submerged aquatic canopies. Water Resour. Res. 43, W04422, doi:10.1029/2006WR005362.

H. M. Nepf & E. R. Vivoni 2000 Flow structure in depth-limited, vegetated flow. J. Geophys. Res. 105 (C12), 2852728546.

I. Nezu & K. Onitsuka 2000 Turbulent structures in partly vegetated open-channel flows with LDA and PIV measurements. J. Hydraul. Res. 39, 629642.

M. Pedras & Lemos, M. de 2000 On the definition of turbulent kinetic energy for flow in porous media. Intl Commun. Heat Mass Transfer 27, 211220.

A. Perry & M. Chong 1987 A description of eddying motions and flow patterns using critical-point concepts. Annu. Rev. Fluid Mech. 19, 125155.

D. Poggi , A. Porporato & L. Ridolfi 2004 aThe effect of vegetation density on canopy sub-layer turbulence. Boundary-Layer Met. 111, 565587.

D. Poggi , G. G. Katul & J. D. Albertson 2004 bA note on the contribution of dispersive fluxes to momentum transfer within canopies. Boundary-Layer Met. 111, 615621.

M. Raupach & M. Thom 1981 Turbulence in and above plant canopies. Annu. Rev. Fluid Mech. 13, 97129.

M. Raupach , J. Finnigan & Y. Brunet 1996 Coherent eddies and turbulence in vegetation canopies: the mixing layer analogy. Boundary-Layer Met. 78, 351382.

M. Schatz , D. Barkley & H. Swinney 1995 Instability in a spatially periodic open flow. Phys. Fluids 7 (2), 344358.

A. Shvidchenko & G. Pender 2001 Macroturbulent structure of open-channel flow over gravel beds. Water Resour. Res. 37, 709719.

S. Socolofsky & G. Jirka 2004 Large scale flow structures and stability in shallow flows. J. Environ. Engng Sci. 3, 451462.

N. Tamai , T. Asaeda & H. Ikeda 1986 Study on generation of periodical large surface eddies in a composite channel flow. Water Resour. Res. 22, 11291138.

W. Uijttewaal & R. Booij 2000 Effects of shallowness on the development of free-surface mixing layers. Phys. Fluids 12, 392402.

W. Uijttewaal & J. Tukker 1998 Development of quasi two-dimensional structures in a shallow free-surface mixing layer. Exps. Fluids 24, 192200.

S. Xiaohui & C. Li 2002 Large eddy simulation of free surface turbulent flow in partly vegetated open channels. Intl J. Numer. Meth. Fluids 39, 919937.

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