Modeling of Surface Roughness for Flow over a Complex Vegetated Surface
Turbulence modeling of large-scale flow over a vegetated surface is complex. Such problems involve large scale computational domains, while the characteristics of flow near the surface are also involved. In modeling large scale flow, surface roughness including vegetation is generally taken into account by mean of roughness parameters in the modified law of the wall. However, the turbulence structure within the canopy region cannot be captured with this method, another method which applies source/sink terms to model plant drag can be used. These models have been developed and tested intensively but with a simple surface geometry. This paper aims to compare the use of roughness parameter, and additional source/sink terms in modeling the effect of plant drag on wind flow over a complex vegetated surface. The RNG k-ε turbulence model with the non-equilibrium wall function was tested with both cases. In addition, the k-ω turbulence model, which is claimed to be computationally stable, was also investigated with the source/sink terms. All numerical results were compared to the experimental results obtained at the study site Mason Bay, Stewart Island, New Zealand. In the near-surface region, it is found that the results obtained by using the source/sink term are more accurate than those using roughness parameters. The k-ω turbulence model with source/sink term is more appropriate as it is more accurate and more computationally stable than the RNG k-ε turbulence model. At higher region, there is no significant difference amongst the results obtained from all simulations.
[1] Finnigan, J.J., "Turbulence in plant canopies," Annu Rev Fluid
Mech, 2000. 32: p. 519-571.
[2] Lancaster, N. and A. Bass, "Influence of vegetation cover on sand
transport by wind: Field studies at Owens Lake, California," Earth
surf. process. landforms, 1998. 23: p. 69-82.
[3] Putten, W.H.V.D., "Establishment of Ammophilla Arenaria ( Marram
Grass) From Culms, Seeds and Rhizomes," The Journal of Applied
Ecology, 1990. 27: p. 188-199.
[4] Mohan, M. and M.K. Tiwari, "Study of momentum transfers within a
vegetation canopy," Proc. Indian Acad. Sci. (Earth Planet. Sci.),
2004. 113: p. 67-72.
[5] Poggi, D., G.G. Katul, and J.D. Albertson, "Momentum transfer and
turbulent kinetic energy budgets within a dense model canopy,"
Boundary-Layer Meteorology, 2004. 111: p. 589-614.
[6] Kim, H.G., V.C. Patel, and C.M. Lee, "Numerical simulation of wind
flow over hilly terrain," Journal of wind engineering and industrial
aerodynamics, 2000. 87: p. 45-60.
[7] Lun, Y.F., et al., "Applicability of linear type revised k ╬Á models to
flow over topographic features," Journal of wind engineering and
industrial aerodynamics, 2007. 95: p. 371-384.
[8] Maurizi, A., J.M.L.M. Palma, and F.A. Castro, "Numerical
simulation of the atmospheric flow in a mountainous region of the
North of Partugal," Journal of wind engineering and industrial
aerodynamics, 1998. 74-76: p. 219-228.
[9] Ayotte, K.W., J.J. Finnigan, and M.R. Raupach, "A second-order
closure for neutrally stratified vegetative canopy flows," Boundary-
Layer Meteorol, 1999. 90: p. 189-216.
[10] Green, S.R., "Modelling turbulent air flow in a stand of widelyspaced
trees," Phoenics J., 1992. 5(294-312).
[11] Katul, G.G., et al., "One- and Two-equation models for canopy
turbulence," Boundary-Layer Meteorol, 2004. 113(80-109).
[12] Neary, V.S., "Numerical solution of fully developed flow," Journal of
engineering mechanics, 2003. 129: p. 558-563.
[13] Sogachev, A. and O. Panferov, "Modification of two-equation
models to account for plant drag," Boundary-Layer Meteorol, 2006.
121: p. 229-266.
[14] Sherman, D.J., et al., "Wind-blown sand on beaches: an evaluation of
models," Geomorphology, 1998. 22: p. 113-133.
[15] Stephen, M. and Z. Xin, "Computational analysis of pressure and
wake characteristics of an aerofoil in ground effect," Journal of fluid
engineering, 2005. 127: p. 290-298.
[16] Launder, B.E. and D.B. Spalding, "The numerical computational of
turbulent flows," Computer methods in applied mechanics and
engineering, 1974. 3: p. 269-289.
[17] Yakhot, V. and S.A. Orszag, "Renormalization group analysis of
turbulence: I. Basic theory," Journal of Scientific Computing, 1986.
1(1): p. 1-51.
[18] Shih, T.-H., et al., "A New k-╬Á eddy-viscosity model for high
Reynolds number turbulent flows model development and
validation," Computers fluids, 1995. 24(3): p. 227-238.
[19] Menter, F.R., "Two-equation eddy-viscosity turbulence models for
engineering applications," AIAA Journal, 1994. 32(8): p. 1598-1605.
[20] Wakes, S.J., et al., "Using Computational Fluid Dynamics to
investigate the effect of a Marram covered foredune; initial results,"
in Seventh International Conference on Modelling, Measurements,
Engineering and Management of Seas and Coastal Regions. 2005:
Algarve, Portugal.
[21] Li Liang, et al., "Improved k-╬Á two-equation turbulence model for
canopy flow," Atmospheric Environment 2006. 40: p. 762-770.
[22] Aynsley, R.M., W. Melbourne, and B.J. Vickery, "Architectural
Aerodynamics," 1977: Applied Science.
[23] Raupach, M.R. and R.H. Shaw, "Averaging procedures for flow
within vegetation canopies," Boundary-Layer Meteorol, 1982. 22: p.
79-90.
[24] Sanz, C., "A note on k − ╬Á modelling of vegetation canopy airflows,"
Boundary-Layer Meteorology, 2003. 108: p. 191-197.
[25] Foudhil, H., Y. Brunet, and J.-P. Caltagirone, "A fine-scale k-╬Á model
for atmospheric flow over heterogeneous landscapes," Environ Fluid
Mech, 2005. 5: p. 247-265.
[26] Liu, J., et al., "E-╬Á modelling of turbulent air flow downwind of a
model forest edge," Boundary-Layer Meteorol 1996. 77: p. 21-44
[27] Blocken, B., T. Stathopoulos, and J. Carmeliet, "CFD simulation of
the atmospheric boundary layer: wall function problems,"
Atmospheric environment 2007. 41: p. 238-252.
[28] Parsons, D.R., et al., "Numerical of airflow over an idealised
transverse dune," Environmental modeling and software, 2004. 19: p.
153-162.
[29] Neff, D.V. and R.N. Meroney, "Wind-tunnel modeling of hill and
vegetation influence on wind power availability," Journal of wind
engineering and industrial aerodynamics, 1998. 74-76: p. 335-343.
[30] Cao, S. and T. Tamura, "Experimental study on roughness effects on
turbulent boundary layer flow over a two-dimensional steep hill,"
Journal of wind engineering and industrial aerodynamics, 2006. 94:
p. 1-19.
[1] Finnigan, J.J., "Turbulence in plant canopies," Annu Rev Fluid
Mech, 2000. 32: p. 519-571.
[2] Lancaster, N. and A. Bass, "Influence of vegetation cover on sand
transport by wind: Field studies at Owens Lake, California," Earth
surf. process. landforms, 1998. 23: p. 69-82.
[3] Putten, W.H.V.D., "Establishment of Ammophilla Arenaria ( Marram
Grass) From Culms, Seeds and Rhizomes," The Journal of Applied
Ecology, 1990. 27: p. 188-199.
[4] Mohan, M. and M.K. Tiwari, "Study of momentum transfers within a
vegetation canopy," Proc. Indian Acad. Sci. (Earth Planet. Sci.),
2004. 113: p. 67-72.
[5] Poggi, D., G.G. Katul, and J.D. Albertson, "Momentum transfer and
turbulent kinetic energy budgets within a dense model canopy,"
Boundary-Layer Meteorology, 2004. 111: p. 589-614.
[6] Kim, H.G., V.C. Patel, and C.M. Lee, "Numerical simulation of wind
flow over hilly terrain," Journal of wind engineering and industrial
aerodynamics, 2000. 87: p. 45-60.
[7] Lun, Y.F., et al., "Applicability of linear type revised k ╬Á models to
flow over topographic features," Journal of wind engineering and
industrial aerodynamics, 2007. 95: p. 371-384.
[8] Maurizi, A., J.M.L.M. Palma, and F.A. Castro, "Numerical
simulation of the atmospheric flow in a mountainous region of the
North of Partugal," Journal of wind engineering and industrial
aerodynamics, 1998. 74-76: p. 219-228.
[9] Ayotte, K.W., J.J. Finnigan, and M.R. Raupach, "A second-order
closure for neutrally stratified vegetative canopy flows," Boundary-
Layer Meteorol, 1999. 90: p. 189-216.
[10] Green, S.R., "Modelling turbulent air flow in a stand of widelyspaced
trees," Phoenics J., 1992. 5(294-312).
[11] Katul, G.G., et al., "One- and Two-equation models for canopy
turbulence," Boundary-Layer Meteorol, 2004. 113(80-109).
[12] Neary, V.S., "Numerical solution of fully developed flow," Journal of
engineering mechanics, 2003. 129: p. 558-563.
[13] Sogachev, A. and O. Panferov, "Modification of two-equation
models to account for plant drag," Boundary-Layer Meteorol, 2006.
121: p. 229-266.
[14] Sherman, D.J., et al., "Wind-blown sand on beaches: an evaluation of
models," Geomorphology, 1998. 22: p. 113-133.
[15] Stephen, M. and Z. Xin, "Computational analysis of pressure and
wake characteristics of an aerofoil in ground effect," Journal of fluid
engineering, 2005. 127: p. 290-298.
[16] Launder, B.E. and D.B. Spalding, "The numerical computational of
turbulent flows," Computer methods in applied mechanics and
engineering, 1974. 3: p. 269-289.
[17] Yakhot, V. and S.A. Orszag, "Renormalization group analysis of
turbulence: I. Basic theory," Journal of Scientific Computing, 1986.
1(1): p. 1-51.
[18] Shih, T.-H., et al., "A New k-╬Á eddy-viscosity model for high
Reynolds number turbulent flows model development and
validation," Computers fluids, 1995. 24(3): p. 227-238.
[19] Menter, F.R., "Two-equation eddy-viscosity turbulence models for
engineering applications," AIAA Journal, 1994. 32(8): p. 1598-1605.
[20] Wakes, S.J., et al., "Using Computational Fluid Dynamics to
investigate the effect of a Marram covered foredune; initial results,"
in Seventh International Conference on Modelling, Measurements,
Engineering and Management of Seas and Coastal Regions. 2005:
Algarve, Portugal.
[21] Li Liang, et al., "Improved k-╬Á two-equation turbulence model for
canopy flow," Atmospheric Environment 2006. 40: p. 762-770.
[22] Aynsley, R.M., W. Melbourne, and B.J. Vickery, "Architectural
Aerodynamics," 1977: Applied Science.
[23] Raupach, M.R. and R.H. Shaw, "Averaging procedures for flow
within vegetation canopies," Boundary-Layer Meteorol, 1982. 22: p.
79-90.
[24] Sanz, C., "A note on k − ╬Á modelling of vegetation canopy airflows,"
Boundary-Layer Meteorology, 2003. 108: p. 191-197.
[25] Foudhil, H., Y. Brunet, and J.-P. Caltagirone, "A fine-scale k-╬Á model
for atmospheric flow over heterogeneous landscapes," Environ Fluid
Mech, 2005. 5: p. 247-265.
[26] Liu, J., et al., "E-╬Á modelling of turbulent air flow downwind of a
model forest edge," Boundary-Layer Meteorol 1996. 77: p. 21-44
[27] Blocken, B., T. Stathopoulos, and J. Carmeliet, "CFD simulation of
the atmospheric boundary layer: wall function problems,"
Atmospheric environment 2007. 41: p. 238-252.
[28] Parsons, D.R., et al., "Numerical of airflow over an idealised
transverse dune," Environmental modeling and software, 2004. 19: p.
153-162.
[29] Neff, D.V. and R.N. Meroney, "Wind-tunnel modeling of hill and
vegetation influence on wind power availability," Journal of wind
engineering and industrial aerodynamics, 1998. 74-76: p. 335-343.
[30] Cao, S. and T. Tamura, "Experimental study on roughness effects on
turbulent boundary layer flow over a two-dimensional steep hill,"
Journal of wind engineering and industrial aerodynamics, 2006. 94:
p. 1-19.
@article{"International Journal of Earth, Energy and Environmental Sciences:52304", author = "Wichai Pattanapol and Sarah J. Wakes and Michael J. Hilton and Katharine J.M. Dickinson", title = "Modeling of Surface Roughness for Flow over a Complex Vegetated Surface", abstract = "Turbulence modeling of large-scale flow over a vegetated surface is complex. Such problems involve large scale computational domains, while the characteristics of flow near the surface are also involved. In modeling large scale flow, surface roughness including vegetation is generally taken into account by mean of roughness parameters in the modified law of the wall. However, the turbulence structure within the canopy region cannot be captured with this method, another method which applies source/sink terms to model plant drag can be used. These models have been developed and tested intensively but with a simple surface geometry. This paper aims to compare the use of roughness parameter, and additional source/sink terms in modeling the effect of plant drag on wind flow over a complex vegetated surface. The RNG k-ε turbulence model with the non-equilibrium wall function was tested with both cases. In addition, the k-ω turbulence model, which is claimed to be computationally stable, was also investigated with the source/sink terms. All numerical results were compared to the experimental results obtained at the study site Mason Bay, Stewart Island, New Zealand. In the near-surface region, it is found that the results obtained by using the source/sink term are more accurate than those using roughness parameters. The k-ω turbulence model with source/sink term is more appropriate as it is more accurate and more computationally stable than the RNG k-ε turbulence model. At higher region, there is no significant difference amongst the results obtained from all simulations.
", keywords = "CFD, canopy flow, surface roughness, turbulence models.", volume = "1", number = "8", pages = "78-9", }
