Browse > Article
http://dx.doi.org/10.12989/was.2014.18.1.069

Effect of trunk length on the flow around a fir tree  

Lee, Jin-Pyung (School of Environmental Science and Engineering, Pohang University of Science and Technology)
Lee, Eui-Jae (Department of Mechanical Engineering, Pohang University of Science and Technology)
Lee, Sang-Joon (Department of Mechanical Engineering, Pohang University of Science and Technology)
Publication Information
Wind and Structures / v.18, no.1, 2014 , pp. 69-82 More about this Journal
Abstract
Flow around a small white fir tree was investigated with varying the length of the bottom trunk (hereafter referred to as bottom gap). The velocity fields around the tree, which was placed in a closed-type wind tunnel test section, were quantitatively measured using particle image velocimetry (PIV) technique. Three different flow regions are observed behind the tree due to the bottom gap effect. Each flow region exhibits a different flow structure as a function of the bottom gap ratio. Depending on the gap ratio, the aerodynamic porosity of the tree changes and the different turbulence structure is induced. As the gap ratio increases, the maximum turbulence intensity is increased as well. However, the location of the local maximum turbulence intensity is nearly invariant. These changes in the flow and turbulence structures around a tree due to the bottom gap variation significantly affect the shelter effect of the tree. The wind-speed reduction is increased and the height of the maximum wind-speed reduction is decreased, as the gap ratio decreases.
Keywords
windbreak; white fir tree; shelter effect; wind tunnel; PIV;
Citations & Related Records
연도 인용수 순위
  • Reference
1 Castro, I.P. (1971), "Wake characteristics of two-dimensional perforated plates normal to an airstream", J. Fluid Mech., 46, 599-609.   DOI
2 Bitog, J.P., Lee, I.B., Shin, M.H., Hong, S.W., Hwang, H.S., Seo, I.H., Yoo, J.I., Kwon, K.S., Kim, Y.H and Han, J.W. (2009), "Numerical simulation of an array of fences in Saemangeum reclaimed land", Atmos. Environ., 43(30), 4612-4621.   DOI   ScienceOn
3 Bourdin, P. and Wilson, J.D. (2008), "Windbreak aerodynamics: is computational fluid dynamics reliable?", Bound.- Lay. Meteorol., 126(2),181-208.   DOI   ScienceOn
4 Cleugh, H.A. (1998), "Effects of windbreaks on airflow, microclimates and crop yields", Agroforest. Syst., 41(1), 55-84.   DOI   ScienceOn
5 Gross, G. (1987), "A numerical study of the air flow within and around a single tree", Bound.- Lay. Meteorol., 40(4), 311-327.   DOI
6 Guan, D., Zhang, Y. and Zhu, T. (2003), "A wind-tunnel study of windbreak drag", Agr. Forest. Meteorol., 118(1-2), 75-84.   DOI   ScienceOn
7 Chen, G., Wang, D., Sun, C. and Li, J. (2012), "3D numerical simulation of wind flow behind a new porous fence", Powder Technol., 230, 118-126.   DOI
8 Hagen, J.L., Skidmore, E.L., Miller, P.L. and Kipp, J.E. (1981), "Simulation of effect of wind barriers on airflow", Trans - ASAE 24, 1002-1008.   DOI
9 Heisler, G.M. and Dewalle, D.R. (1988), "Effects of windbreak structure on wind flow", Agr. Ecosyst. Environ., 22, 41-69.
10 Judd, M.J., Raupach, M.R. and Finnigan, J.J. (1996), "A wind tunnel study of turbulent flow around single and multiple windbreaks, part I: Velocity fields", Bound.- Lay. Meteorol., 80(1-2), 127-165   DOI
11 Kim, H.B. and Lee, S.J. (2002), "The structure of turbulent shear flow around a two-dimensional porous fence having a bottom gap", J. Fluid. Struct., 16(3), 317-329.   DOI   ScienceOn
12 Melese, E.A., Hertog, M., Delele, M.A., Baetens, K., Persoons, T., Baelmans, M., Ramon, H., Nicolai, B.M. and Verboven, P. (2009) "CFD modelling and wind tunnel validation of airflow through plant canopies using 3D canopy architecture", Int. J. Heat Fluid Fl., 30(2), 356-368.   DOI   ScienceOn
13 Perera, M.D.A.S. (1981), "Shelter behind two-dimensional solid and porous fences", J. Wind Eng. Ind. Aerod., 8(1-2), 93-104.   DOI   ScienceOn
14 Raine, J.K. and Stevenson, D.C. (1977), "Wind protection by model fences in a simulated atmospheric boundary layer", J. Wind Eng. Ind. Aerod., 2(2), 17-39.
15 Wang, H., Takle, E.S. and Shen, J. (2001) "Shelterbelts and windbreaks: mathematical modeling and computer simulations of turbulent flows", Annu. Rev. Fluid Mech., 33, 549-586.   DOI   ScienceOn
16 Rosendfeld, M., Marom, G. and Bitan, A. (2010), "Numerical simulation of the airflow across trees in a windbreak", Bound. - Lay. Meteorol., 135(1), 89-107.   DOI
17 Torita, H. and Satou, H. (2007), "Relationship between shelterbelt structure and mean wind reduction", Agr. Forest. Meteorol., 145(3-4), 186-194.   DOI   ScienceOn
18 van Eimern, J., Karschon, R., Razumova, L.A. and Robertson, G.W. (1964), Windbreaks and Shelterbelts, W.M.O. Tech. Note No. 59.