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The creation and evolution of coherent structures in plant canopy flows and their role in turbulent transport

Published online by Cambridge University Press:  21 January 2016

Brian N. Bailey  and
R. Stoll
Brian N. Bailey*
Affiliation:
Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA
R. Stoll
Affiliation:
Department of Mechanical Engineering, University of Utah, Salt Lake City, UT 84112, USA
*
†Email address for correspondence: [email protected]
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Abstract

In this paper we used simulation tools to study turbulent boundary-layer structures in the roughness sublayer. Of particular interest is the case of a neutrally-stratified atmospheric boundary layer in which the lower boundary is covered by a homogeneous plant canopy. The goal of this study was to formulate a consistent conceptual model for the creation and evolution of the dominant coherent structures associated with canopy roughness and how they link with features observed in the overlying inertial sublayer. First, coherent structures were examined using temporally developing flow where the full range of turbulent scales had not yet developed, which allowed for instantaneous visualizations. These visualizations were used to formulate a conceptual model, which was then further tested using composite-averaged structure realizations from fully-developed flow with a very large Reynolds number. This study concluded that quasi two-dimensional mixing-layer-like roller structures exist in the developed flow and give the largest contributions to mean Reynolds stresses near the canopy. This work fully acknowledges the presence of highly three-dimensional and localized vortex pairing processes. The primary argument is that, as in a mixing layer, the smaller three-dimensional vortex interactions do not destroy the larger two-dimensional structure. Because the flow has a very large Reynolds number, the roller-like structures are not well-defined vortices but rather are a conglomerate of a large range of smaller-scale vortex structures that create irregularities. Because of this, the larger-scale structure is more difficult to detect in correlation or conditional sampling analyses. The frequently reported ‘scalar microfronts’ and associated spikes in pressure occur in the slip-like region between adjacent rollers. As smaller vortices within roller structures stretch, they evolve to form arch- and hairpin-shaped structures. Blocking by the low-flux canopy creates vertical asymmetry, and tends to impede the vertical progression of head-down structures. Head-up hairpins are allowed to continually stretch upward into the overlying inertial sublayer, where they evolve into the hairpin structures commonly reported to populate wall-bounded flows. This process is thought to be modulated by boundary-layer-scale secondary instability, which enhances head-up hairpin formation along quasi-streamwise transects.

JFM classification

Geophysical and Geological Flows: Atmospheric flows Boundary Layers: Boundary layer structure Turbulent Flows: Shear layer turbulence
Type
Papers
Information
Journal of Fluid Mechanics , Volume 789 , 25 February 2016 , pp. 425 - 460
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© 2016 Cambridge University Press 

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References

Adrian, R. J. 2013 Structure of turbulent boundary layers. In Coherent Flow Structures at Earth’s Surface, 2nd edn (ed. Venditti, J. G., Best, J. L., Church, M. & Hardy, R. J.), pp. 17–24. John Wiley and Sons.Google Scholar
Adrian, R. J. & Liu, Z. C. 2002 Observation of vortex packets in direct numerical simulation of fully turbulent channel flow. J. Vis. 5, 9–19.CrossRefGoogle Scholar
Adrian, R. J., Meinhart, C. D. & Tomkins, C. D. 2000 Vortex organization in the outer region of the turbulent boundary layer. J. Fluid Mech. 422, 1–54.Google Scholar
Ashurst, W. T. & Meiburg, E. 1988 Three-dimensional shear layers via vortex dynamics. J. Fluid Mech. 189, 87–116.Google Scholar
Bailey, B. N. & Stoll, R. 2013 Turbulence in sparse organized vegetative canopies: a large-eddy simulation study. Boundary-Layer Meteorol. 147, 369–400.CrossRefGoogle Scholar
Bailey, B. N., Stoll, R., Pardyjak, E. R. & Mahaffee, W. F. 2014 Effect of canopy architecture on vertical transport of massless particles. Atmos. Environ. 95, 480–489.Google Scholar
Baldocchi, D. D. & Hutchinson, B. A. 1987 Turbulence in an almond orchard: vertical variation in turbulence statistics. Boundary-Layer Meteorol. 40, 127–146.Google Scholar
Barros, J. M. & Christensen, K. T. 2014 Observations of turbulent secondary flows in a rough-wall boundary layer. J. Fluid Mech. 748, R1–13.Google Scholar
Barthlott, C., Drobinski, P., Fesquet, C., Dubos, T. & Pietras, C. 2007 Long-term study of coherent structures in the atmospheric surface layer. Boundary-Layer Meteorol. 125, 1–24.Google Scholar
Bell, J. H. & Mehta, R. D. 1990 Development of a two-stream mixing layer from tripped and untriped boundary layers. AIAA J. 28, 2034–2042.Google Scholar
Bernal, L. P., Breidenthal, R. E., Brown, G. L., Konrad, J. H. & Roshko, A. 1979 On the development of three dimensional small scales in turbulent mixing layers. In Proceedings of the 2nd International Symposium on Turbulent Shear Flows, Imperial College, pp. 8.1–8.6.Google Scholar
Breidenthal, R. E.1978 A chemically reacting turbulent shear layer. PhD thesis, California Insitute of Technology.Google Scholar
Browand, F. K. & Troutt, T. R. 1980 A note on spanwise structure in the two-dimensional mixing layer. J. Fluid Mech. 97, 771–781.CrossRefGoogle Scholar
Browand, F. K. & Troutt, T. R. 1985 The turbulent mixing layer: geometry of large vortices. J. Fluid Mech. 158, 489–509.Google Scholar
Brunet, Y., Finnigan, J. J. & Raupach, M. R. 1994 A wind tunnel study of air flow in waving wheat: single-point velocity statistics. Boundary-Layer Meteorol. 70, 95–132.Google Scholar
Brunet, Y. & Irvine, M. R. 2000 The control of coherent eddies in vegetation canopies: streamwise structure spacing, canopy shear scale and atmospheric stability. Boundary-Layer Meteorol. 94, 139–163.Google Scholar
Canuto, C., Hussaini, M. Y., Quarteroni, A. & Zang, T. A. 1988 Spectral Methods in Fluid Dynamics, p. 568. Springer.Google Scholar
Chen, C. H. P. & Blackwelder, R. F. 1978 Large-scale motion in a turbulent boundary layer: a study using temperature contamination. J. Fluid Mech. 89, 1–31.CrossRefGoogle Scholar
Christen, A. & Vogt, R. 2004 Direct measurement of dispersive fluxes within a cork oak plantation. In Proceedings of the 26th Conference on Agricultural and Forest Meteorology, American Meteorological Society.Google Scholar
Clark, J. A. & Markland, E. 1971 Flow visualization in turbulent boundary layers. J. Hydraul. Div. ASCE 97, 1653–1664.Google Scholar
Coceal, O., Dobre, A., Thomas, T. G. & Belcher, S. E. 2007 Structure of turbulent flow over regular arrays of cubical roughness. J. Fluid Mech. 589, 375–409.Google Scholar
Collis, S. S., Lele, S. K., Moser, R. D. & Rogers, M. M. 1994 The evolution of a plane mixing layer with spanwise nonuniform forcing. Phys. Fluids 6, 381–396.CrossRefGoogle Scholar
Comte, P., Lesieur, M. & Lamballais, E. 1992 Large- and small-scale stirring of vorticity and a passive scalar in a 3-D temporal mixing layer. Phys. Fluids A 4, 2761–2778.Google Scholar
Comte, P., Silvestrini, J. H. & Bégou, P. 1998 Steamwise vortices in large-eddy simulations of mixing layers. Eur. J. Mech. (B/Fluids) 4, 615–637.Google Scholar
Fang, J. & Porté-Agel, F. 2015 Large-eddy simulation of very-large-scale motinos in the neutrally stratified atmospheric boundary layer. Boundary-Layer Meteorol. 155, 397–416.Google Scholar
Finnigan, J. J. 2000 Turbulence in plant canopies. Annu. Rev. Fluid Mech. 32, 519–571.CrossRefGoogle Scholar
Finnigan, J. J. & Shaw, R. H. 2000 A wind tunnel study of airflow in waving wheat: an EOF analysis of the structure of the large-eddy motion. Boundary-Layer Meteorol. 96, 211–255.Google Scholar
Finnigan, J. J. & Shaw, R. H. 2008 Double-averaging methodology and its application to turbulent flow in and above vegetation canopies. Environ. Sci. Technol. 56, 534–561.Google Scholar
Finnigan, J. J., Shaw, R. H. & Patton, E. G. 2009 Turbulence structure above a vegetation canopy. J. Fluid Mech. 637, 387–424.Google Scholar
Fitzmaurice, L., Shaw, R. H., Paw, U. K. T. & Patton, E. G. 2004 Three-dimensional scalar microfront systems in a large-eddy simulation of vegetation canopy flow. Boundary-Layer Meteorol. 112, 107–127.CrossRefGoogle Scholar
Ganapathisubramani, B., Longmire, E. K. & Marusic, I. 2003 Characteristics of vortex packets in turbulent boundary layers. J. Fluid Mech. 478, 35–46.Google Scholar
Gao, W., Shaw, R. H. & Paw, U. K. T. 1989 Observation of organized structure in turbulent flow within and above a forest canopy. Boundary-Layer Meteorol. 47, 349–377.CrossRefGoogle Scholar
Gerz, T., Howell, J. & Mahrt, L. 1994 Vortex structures and microfronts. Phys. Fluids 6, 1242–1251.Google Scholar
Ghisalberti, M. 2010 The three-dimensionality of obstructed shear flows. Environ. Fluid Mech. 10, 329–343.Google Scholar
Green, M. A., Rowley, C. W. & Haller, G. 2007 Detection of Lagrangian coherent structures in 3D turbulence. J. Fluid Mech. 572, 111–120.Google Scholar
Guala, M., Tomkins, C. D., Christensen, K. T. & Adrian, R. J. 2012 Vortex organization in a turbulent boundary layer overlying sparse roughness elements. J. Hydraul. Res. 50, 465–481.Google Scholar
Haller, G. 2005 An objective definition of a vortex. J. Fluid Mech. 525, 1–26.Google Scholar
Head, M. R. & Bandyopadhyay, P. 1981 New aspects of turbulent boundary layer structure. J. Fluid Mech. 107, 297–338.Google Scholar
Herbert, T. 1988 Secondary instability of boundary layers. Annu. Rev. Fluid Mech. 20, 487–526.Google Scholar
Holmes, P., Lumley, J. L., Berkooz, G. & Rowley, C. W. 2012 Turbulence, Coherent Structures, Dynamical Systems and Symmetry, 2nd edn. p. 386. Cambridge University Press.Google Scholar
Holt, J. T. 1998 Experiments on Kelvin–Helmholtz billows influenced by boundaries. Geophys. Astrophys. Fluid Dyn. 89, 205–233.Google Scholar
Hommema, S. E. & Adrian, R. J. 2003 Packet structure of surface eddies in the atmospheric boundary layer. Boundary-Layer Meteorol. 106, 147–170.CrossRefGoogle Scholar
Huang, L.-S. & Ho, C.-M 1990 Small-scale transition in a plane mixing layer. J. Fluid Mech. 210, 475–500.Google Scholar
Huerre, P. & Monkewitz, P. A. 1985 Absolute and convective instabilities in free shear layers. J. Fluid Mech. 159, 151–168.Google Scholar
Hunt, J. C., Wray, A. A. & Moin, P.1988 Eddies, stream, and convergence zones in turbulent flows. Tech. Rep. CTR-S88. Center for Turbulence Research, p. 193.Google Scholar
Hutchins, N. & Marusic, I. 2007 Evidence of very long meandering features in the logarithmic region of turbulent boundary layers. J. Fluid Mech. 579, 1–28.CrossRefGoogle Scholar
Jeong, J. & Hussein, F. 1995 On the identification of a vortex. J. Fluid Mech. 285, 69–94.Google Scholar
Jiménez, J., Álamo, J. C. Del & Flores, O. 2004 The large-scale dynamics of near-wall turbulence. J. Fluid Mech. 505, 179–199.Google Scholar
Kim, J. & Moin, P. 1986 The structure of the vorticity field in turbulent channel flow. Part 2. Study of ensemble-averaged fields. J. Fluid Mech. 162, 339–363.Google Scholar
Kim, K. C. & Adrian, R. J. 1999 Very large-scale motion in the outer layer. Phys. Fluids 11, 417–422.Google Scholar
Klebanoff, P. S., Tidstrom, K. D. & Sargent, L. M. 1962 The three-dimensional nature of boundary-layer instability. J. Fluid Mech. 12, 1–34.Google Scholar
Lasheras, J. C. & Choi, H. 1988 Three-dimensional instability of a plane free shear layer: an experimental study of the formation and evolutionj of streamwise vortices. J. Fluid Mech. 189, 53–86.CrossRefGoogle Scholar
Lin, S. J. & Corcos, G. M. 1984 The mixing layer: deterministic models of a turbulent flow. Part 3. The effect of plane strain on the dynamics of streamwise vortices. J. Fluid Mech. 141, 139–178.CrossRefGoogle Scholar
Lindzen, R. S. & Rosenthal, A. J. 1976 On the instability of Helmholtz velocity profiles in stably stratified fluid when a lower boundary is present. J. Geophys. Res. 81, 1561–1571.Google Scholar
Lu, S. S. & Willmarth, W. W. 1973 Measurements of the structure of Reynolds stress in a turbulent boundary layer. J. Fluid Mech. 60, 481–571.Google Scholar
Mahrt, L. 1991 Eddy asymmetry in the sheared heated boundary layer. J. Atmos. Sci. 483, 472–492.Google Scholar
Mathis, R., Hutchins, N. & Marusic, I. 2009 Large-scale amplitude modulation of the small-scale structures in turbulent boundary layers. J. Fluid Mech. 628, 311–377.Google Scholar
Metcalfe, R. W., Hussain, F., Menon, S. & Hayakawa, M. 1985 Coherent structures in a turbulent mixing layer: a comparison between numerical simulations and experiments. In Turbulent Shear Flows 5 (ed. Durst, F., Launder, B. E., Lumley, J. L., Schmidt, F. W. & Whitelaw, J. H.), pp. 110–123. Springer.Google Scholar
Michalke, A. 1965 On the inviscid instability of the hyperbolic-tangent velocity profile. J. Fluid Mech. 19, 543–556.CrossRefGoogle Scholar
Moser, R. D. & Rogers, M. M. 1991 Mixing transition and the cascade to small scales in a plane mixing layer. Phys. Fluids A 3, 1128.CrossRefGoogle Scholar
Nyggard, K. J. & Glezer, A. 1991 Evolution of streamwise vortices and generation of small-scale motion in a plane mixing layer. J. Fluid Mech. 231, 257–301.CrossRefGoogle Scholar
Offen, G. R. & Kline, S. J. 1975 A proposed model of the bursting process in turbulent boundary layers. J. Fluid Mech. 70, 209–228.CrossRefGoogle Scholar
Pan, Y., Chamecki, M. & Isard, S. A. 2014 Large-eddy simulation of turbulence and particle dispersion inside the canopy roughness sublayer. J. Fluid Mech. 753, 499–534.CrossRefGoogle Scholar
Paw, U. K. T., Brunet, Y., Collineau, S., Shaw, R. H., Maitani, T., Qiu, J. & Hipps, L. 1992 On coherent structures in turbulence above and within agricultural plant canopies. Agric. Forest Meteorol. 61, 55–68.Google Scholar
Perret, L. & Ruiz, T. 2013 SPIV analysis of coherent structures in a vegetation canopy model flow. In Coherent Flow Structures at Earth’s Surface (ed. Venditti, J. G., Best, J. L., Church, M. & Hardy, R. J.), pp. 161–174. John Wiley and Sons.Google Scholar
Pierrehumbert, R. T. & Widnall, S. E. 1982 The two- and three-dimensional instabilities of a spatially periodic shear layer. J. Fluid Mech. 114, 59–82.Google Scholar
Raupach, M. R. 1981 Conditional statistics of Reynolds stress in rough-wall and smooth-wall turbulent boundary layers. J. Fluid Mech. 108, 363–382.Google Scholar
Raupach, M. R., Finnigan, J. J. & Brunet, Y. 1996 Coherent eddies and turbulence in vegetation canopies: the mixing-layer analogy. Boundary-Layer Meteorol. 78, 351–382.Google Scholar
Raupach, M. R. & Thom, A. S. 1981 Turbulence in and above plant canopies. Annu. Rev. Fluid Mech. 13, 97–129.Google Scholar
Reynolds, R. T., Hayden, P., Castro, I. P. & Robins, A. G. 2007 Spanwise variations in nominally two-dimensional rough-wall boundary layers. Exp. Fluids 42, 311–320.CrossRefGoogle Scholar
Robinson, S. K. 1991 Coherent motions in the turbulent boundary layer. Annu. Rev. Fluid Mech. 23, 601–639.Google Scholar
Rogers, M. M. & Moin, P. 1987 The structure of the vorticity field in homogeneous turbulent flows. J. Fluid Mech. 176, 33–66.Google Scholar
Rogers, M. M. & Moser, R. D. 1992 The three-dimensional evolution of a plane mixing layer: the Kelvin–Helmholtz rollup. J. Fluid Mech. 243, 183–226.Google Scholar
Rogers, M. M. & Moser, R. D. 1994 Direct simulation of a self-similar turbulent mixing layer. Phys. Fluids 6, 903–923.Google Scholar
Saric, W. S. & Thomas, A. S. W. 1984 Experiments on the subharmonic route to turbulence in boundary layers. In Turbulence and Chaotic Phenomena in Fluids (ed. Tatsumi, T.), pp. 117–122. Elsevier.Google Scholar
Shaw, R. H., Brunet, Y., Finnigan, J. J. & Raupach, M. R. 1995 A wind tunnel study of air flow in waving wheat: two-point velocity statistics. Boundary-Layer Meteorol. 76, 349–376.Google Scholar
Shaw, R. H., Paw, U. K. T. & Gao, W. 1989 Detection of temperature ramps and flow structures at a deciduous forest site. Agric. Forest Meteorol. 47, 123–138.Google Scholar
Shaw, R. H. & Schumann, U. 1992 Large-eddy simulation of turbulent flow above and within a forest. Boundary-Layer Meteorol. 61, 47–64.Google Scholar
Stoll, R. & Porté-Agel, F. 2006a Dynamic subgrid-scale models for momentum and scalar fluxes in large-eddy simulations of neutrally stratified atmospheric boundary layers over heterogeneous terrain. Water Resour. Res. 42, W01409.Google Scholar
Stoll, R. & Porté-Agel, F. 2006b Effect of roughness on surface boundary conditions for large-eddy simulation. Boundary-Layer Meteorol. 118, 169–187.Google Scholar
Tanahashi, M., Iwase, S. & Miyauchi, T. 2001 Appearance and alignment with strain rate of coherent fine scale eddies in turbulent mixing layer. J. Turbul. 2, 006.Google Scholar
Tay, G. F. K., Kuhn, D. C. S. & Tachie, M. F. 2013 Surface roughness effects on the turbulence statistics in a low Reynolds number channel flow. J. Turbul. 14, 121–146.Google Scholar
Wang, Y., Tanahashi, M. & Miyauchi, T. 2007 Coherent fine scale eddies in turbulence transition of spatially-developing mixng layer. Intl J. Heat Fluid Flow 28, 1280–1290.Google Scholar
Watanabe, T. 2004 Large-eddy simulation of coherent turbulence structures associated with scalar ramps over plant canopies. Boundary-Layer Meteorol. 112, 307–341.CrossRefGoogle Scholar
Wu, Y. & Christensen, K. T. 2010 Spatial structure of a turbulent boundary layer with irregular surface roughness. J. Fluid Mech. 655, 380–418.CrossRefGoogle Scholar
Zhou, J., Adrian, R. J., Balachandar, S. & Kendall, T. M. 1999 Mechanisms for generating coherent packets of hairpin vortices in channel flow. J. Fluid Mech. 387, 353–396.Google Scholar

Bailey and Stoll supplementary movie

Animation of the time evolution of the start-up canopy flow. Coherent vortex structures are visualized by plotting isosurfaces of λ2 at 1% of its minimum value. For visual clarity, isosurfaces are colored by vertical height.

Download Bailey and Stoll supplementary movie(Video)
Video 2.8 MB

Bailey and Stoll supplementary movie

Animation of the time evolution of the composite eddy structure. The structure was educed by composite averaging based on local maxima in pressure at the canopy top. The time evolution of the structure was found by composite averaging a fixed volume at separate instances in time before and after the triggering event. The structures are visualized by plotting isosurfaces of λ2 at 1% of its minimum value. Isosurfaces are colored by fluctuations in the resolved vertical velocity.

Download Bailey and Stoll supplementary movie(Video)
Video 510.6 KB

Bailey and Stoll supplementary movie

Animation of the time evolution of the composite eddy structure. The structure was educed by composite averaging based on local maxima in -(u′ w′) at the canopy top. The time evolution of the structure was found by composite averaging a fixed volume at separate instances in time before and after the triggering event. The structures are visualized by plotting isosurfaces of λ2 at 1% of its minimum value. Isosurfaces are colored by fluctuations in the resolved vertical velocity.

Download Bailey and Stoll supplementary movie(Video)
Video 525.6 KB