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Yu Kejie, Shao Chuanping. WIND TUNNEL INVESTIGATION OF THE AERODYNAMIC CHARACTERISTICS OF PURPLE WISTERIA COMPOUND LEAVES[J]. Chinese Journal of Theoretical and Applied Mechanics, 2019, 51(1): 245-262. doi: 10.6052/0459-1879-18-140
Citation: Yu Kejie, Shao Chuanping. WIND TUNNEL INVESTIGATION OF THE AERODYNAMIC CHARACTERISTICS OF PURPLE WISTERIA COMPOUND LEAVES[J]. Chinese Journal of Theoretical and Applied Mechanics, 2019, 51(1): 245-262. doi: 10.6052/0459-1879-18-140


doi: 10.6052/0459-1879-18-140
  • Publish Date: 2019-01-18
  • The capability of reconfiguration of tree leaves is of significance in the designs of solar panel, aerofoil, bionic antenna, and wind power generation tree. The leaf was clamped at the base end of the rachis and vertically suspended in the center of wind tunnel test section, and tested with its front and back surface facing on-coming stream respectively at step-by-step increasing wind speed from 0 to 25 m/s. Results show that the changing process of the leaf can be divided into three stages: earlier steady, intermediate transition, and later steady, and critical wind speeds are observed. In earlier stage, the downstream bending curvature of the rachis increases rapidly with wind speed, and multi-layer wing steady and multi-layer multi-shape steady states exist. In intermediate stage, large amplitude low frequency rachis vibration, and small amplitude high frequency lobules vibration are observed. In later steady stage, two-layer structure or single streamlined body of conic, or wedge or U-shape cross section can be found. As wind speed increasing, the number of lobule layers and the width of the compound leaf $b$ decrease, until the single streamlined body formed. As $Re$ increasing, the drag coefficient of the leaf decreases rapidly at first, then slowly approaching to a constant. The absolute value of the negative Vogel component $\vert \alpha \vert$ decreases with the increase of lobule number of the leaf. $\vert \alpha \vert $ of the leaf with its back surface is larger than that with its front surface facing wind, but they tend to converge with the increase of lobule number. Rachis vibration occurs if the frequency of vortex shedding from the leaf is close to the natural frequency of the rachis. The second critical wind speed $V_2/\sqrt{E/\rho}$, at which the rachis vibration begins, is shown to be the function of $b/l$ and $d/l$, where $E, \rho , d, $and $l$ are respectively elastic module, mass density, diameter and length of the rachis, $b$ is width of the deformed leaf, and a figure about this function is drawn using experimental data.


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  • [1] Bohdan K, Peter Z, Ján K.Wind-an important ecological factor and destructive agent in forests. Forestry Journal, 2016, 62(2):123-130
    [2] Moore GM.Wind-thrown trees: Storms or management. Arboriculture & Urban Forestry, 2014, 40(2): 53-69
    [3] Cleugh HA, Miller JM, Bohm M.Direct mechanical effects of wind on crops. Agroforestry Systems, 1998, 41: 85-112
    [4] Wu T, Zhang P, Zhang L, et al.Morphological response of eight quercus species to simulated wind load. Plos One, 2016, 11(9): e0163613
    [5] Speck HO, Hurd CL, Speck T.Reconfiguration as a prerequisite for survival in highly unstable flow-dominated habitats. Journal of Plant Growth Regulation, 2004, 23(2): 98-107
    [6] Steinberg V.Hydrodynamics: Bend and survive. Nature, 2002, 420(6915): 473
    [7] Hadhazy A.Power plants: Artificial trees that harvest sun and wind to generate electricity. Scientific American, 2009, 306(5): 31-32
    [8] SharifS, Gentry TR, Yen J, Goodman JN. Transformative solar panels: A multidisciplinary approach. International Journal of Architectural Computing, 2013, 11(2): 227-245
    [9] 陈志超, 詹家礼, 周斌等. 基于仿生学理论的机翼结构布局设计. 机电产品开发与创新, 2014, 27(3): 12-14
    [9] (Chen Zhichao, Zhan Jiali, Zhou Bin, et al.Wing structural layout design based on bionics theory. Development & Innovation of Machinery & Electrical Products, 2014, 27(3): 12-14 (in Chinese))
    [10] 张昊明. 银杏叶状仿生天线的构想与设计. 新疆师范大学学报, 2012, 31(1): 33-40
    [10] (Zhang Haoming.The Design of a Bionic Antenna. Journal of Xinjiang Normal University (Natural Sciences Edition), 2012, 31(1): 33-40 (in Chinese))
    [11] Vogel S.Drag and reconfiguration of broad leaves in high winds. Journal of Experimental Botany, 1989, 40(217): 941-948
    [12] Albayrak I, Nikora V, Miler O, et al.Flow--plant interactions at leaf, stem and shoot scales: Drag, turbulence, and biomechanics. Aquatic Sciences, 2014, 76(2): 269-294
    [13] Speck O.Field measurements of wind speed and reconfiguration in Arundo donax (Poaceae) with estimates of drag forces. American Journal of Botany, 2003, 90(8): 1253-1256
    [14] King M, Vincent JV, Warwick H.Curling and folding of leaves of monocotyledons-a strategy for structural stiffness. New Zealand Journal of Botany, 1996, 34(3): 411-416
    [15] Albayrak I, Nikora V, Miller O, et al.Effects of plant leaf shape on drag forces imposed by water flow.. Sbe.hw.ac.uk, 2010
    [16] Miller LA, Santhanakrishnan A, Jones S, et al.Reconfiguration and the reduction of vortex-induced vibrations in broad leaves. Journal of Experimental Biology, 2012, 215(Pt 15): 2716
    [17] Schouveiler L, Boudaoud A.The rolling up of sheets in a steady flow. Journal of Fluid Mechanics, 2006, 563(563): 71-80
    [18] 邵传平, 朱园园. 鹅掌楸树叶在风中的变形与振动. 力学学报, 2017, 49(2): 431-440
    [18] (Shao Chuanping, Zhu Yuanyuan.The deformation and vibration of tulip leaves in wind. Chinese Journal of Theoretical and Applied Mechanics, 2017, 49(2): 431-440 (in Chinese))
    [19] Shao CP, Chen YJ, Lin JZ.Wind induced deformation and vibration of a Platanus acerifolia leaf. Acta Mechnica Sinica, 2012, 28(3): 583-594
    [20] Tadrist L, Julio K, Saudreau M, et al.Leaf flutter by torsional galloping: Experiments and model. Journal of Fluids & Structures, 2015, 56: 1-10
    [21] Vogel S.Twist-to-bend ratios and cross-sectional shapes of petioles and stems. Journal of Experimental Botany, 1992, 43: 1527-1532
    [22] Etnier SA.Twisting and bending of biological beams: Distribution of biological beams in a stiffness mechanospace. The Biological Bulletin, 2003, 205: 36-46
    [23] Zhao Z, Huang W, Li B, et al.Synergistic effects of chiral morphology and reconfiguration in cattop leaves. Journal of Bionic Engineering, 2015, 12(4): 634-642
    [24] Niklas KJ.A mechanical perspective on foliage leaf form and function. New Phytologist, 1999, 143(1): 19-31
    [25] Grant RH.The scaling of flow in vegetative structures. Boundary-Layer Meteorology, 1983, 27(2): 171-184
    [26] Guan DX, Zhu TY, Han SJ.Wind tunnel experiment of drag of isolated tree models in surface boundary layer. Journal of Forestry Research, 2000, 11(3): 156-160
    [27] O'Hare MT, Hutchinson KA, Clarke RT. The drag and reconfiguration experienced by five macrophytes from a lowland river. Aquatic Botany, 2007 , 86(3): 253-259
    [28] Holland MR, Grace J, Hedley CL.Momentum absorption by dried-pea crops. I. Field measurements over and within varieties of differing leaf structure. Agricultural & Forest Meteorology, 1991, 54(1): 67-79
    [29] Holland MR, Grace J, Hedley CL.Momentum absorption by dried-pea crops. II. Wind tunnel measurements of drag on isolated leaves and pods. Agricultural & Forest Meteorology, 1991, 54(1): 81-93
    [30] Ristroph L, Zhang J.Anomalous hydrodynamic drafting of interacting flapping flags. Physical Review Letters, 2008, 101(19): 194502
    [31] Sang JL, Kim JJ, Yeom E.Vortex-induced reconfiguration of a tandem arrangement of flexible cylinders. Wind & Structures An International Journal, 2015, 21(1): 25-40
    [32] Roshko A.On the wake and drag of bluff bodies. Journal of Aeronautical Science, 1955, 22(2):124-132.
    [33] Alben S.The flapping-flag instability as a nonlinear eigenvalue problem, Physics of Fluids, 2008, 20: 104106
    [34] Alben S, Shelley MJ.Flapping states of a flag in an inviscid fluid:bistability and the transition to chaos. it Physical Review Letters, 2008, 100: 074301
    [35] Chen M, Jia LB, Wu YF, et al.Bifurcation and chaos of a flag in an inviscid flow. Journal of Fluids and Structures, 2014, 45: 124-137
    [36] Eloy C, Souilliez C, Schouveiler L.Flutter of a rectangular plate. Journal of Fluids andStructures, 2007, 23(6): 904-919
    [37] Eloy C, Kofman N, Schouveiler L.The origin of hysteresis in the flag instability. Journal of Fluid Mechanics, 2012, 691(1): 583-593
    [38] Watanabe Y, Suzuki S, Sugihara M.An experimental study of paper flutter. Journal of Fluids and Structures, 2002, 16(4): 529-542
    [39] Watanabe Y, Isogai K, Suzuki S, et al.A theoretical study of paper flutter. Journal of Fluids and Structures, 2002, 16(4): 543-560
    [40] Tian FB, Lu XY, Luo HX.Onset of instability of a flag in uniform flow. Thoeretical & Applied Mechanics Letters, 2012, 2: 022005
    [41] Yu ZS, Wang Y, Shao XM.Numerical simulations of the flapping of a three-dimensional flexible plate in uniform flow. Journal of Sound and Vibration, 2012, 331: 4448-4463
    [42] Tian FB.Role of mass on the stability of flag/flags in uniform flow. Applied Physics Letters, 2013, 103(3): 034101
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