数值模拟气流特征和砾石几何参数对床面空气动力学粗糙度的影响
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摘要
本文应用流体计算软件FLUENT6.3,采用非结构化网格划分技术模拟了气流特征和砾石几何参数对床面空气动力学粗糙度的影响。结果表明:空气动力学粗糙度(z0)与风速(u)、摩阻速度(u*)之间存在定量关系:z0=a exp(bu/u*)。砾石高度对空气动力学粗糙度的影响显著优于砾石直径,空气动力学粗糙度随砾石密度的变化比较复杂,先增加后减小。FLUENT在模拟风洞砾石床面动力学过程中的成功应用,是我们在研究方法上的一次有益尝试。
In this paper,using FLUENT6.3 we simulate effect of wind flow and gravels′geometric parameters on aerodynamic roughness length.The results indicate that aerodynamic roughness is a function of wind flow,and the variation of aerodynamic roughness(z0)with wind speed(u),friction velocity(u*)can be expressed by an exponential fuction:z0=aexp(bu/u*).Gravel height has more significant influence on aerodynamic roughness length than gravel sizes;the aerodynamic roughness increases firstly with gravel density,then decreases.The successful application of FLUENT6.3in simulation of aerodynamic process of gravel beds is a beneficial attempt.
In this paper,using FLUENT6.3 we simulate effect of wind flow and gravels′geometric parameters on aerodynamic roughness length.The results indicate that aerodynamic roughness is a function of wind flow,and the variation of aerodynamic roughness(z0)with wind speed(u),friction velocity(u*)can be expressed by an exponential fuction:z0=aexp(bu/u*).Gravel height has more significant influence on aerodynamic roughness length than gravel sizes;the aerodynamic roughness increases firstly with gravel density,then decreases.The successful application of FLUENT6.3in simulation of aerodynamic process of gravel beds is a beneficial attempt.
引文
[1]董治宝,Fryrear D F,高尚玉.直立植物防沙措施粗糙特征的模拟实验[J].中国沙漠,2000,20(3):260-263.
[2]Bagnold R A.The Physics of Blown Sand and Desert Dunes[M].New York,USA:Methuen,1941:85-95,265.
[3]李振山,陈广庭.粗糙度研究的现状及展望[J].中国沙漠,1997,17(1):99-102.
[4]刘小平,董治宝.砾石床面的空气动力学粗糙度[J].中国沙漠,2003,23(1):38-45.
[5]Lettau H.Note on aerodynamic roughness-parameter estimation on the basis of roughness-elements description[J].Journal of Applied Meteorology,1969,8:828-832.
[6]薛娴,张伟民,王涛.戈壁砾石防护效应的风洞实验与野外观测结果[J].地理学报,2000,55(3):375-383.
[7]Dong Z B,Liu X P,Wang X M.Aerodynamic roughness of gravel surfaces[J].Geomorphology,2002,43:17-31.
[8]梅凡民,蒋缠文,江姗姗,等.粗糙元几何参数的交互作用对床面空气动力学粗糙度的影响[J].中国沙漠,2012,32(6):1534-1541.
[9]王训明,郎丽丽,花婷,等.戈壁砾石覆盖度与风蚀强度关系实验研究[J].中国沙漠,2013,33(2):313-319.
[10]Zilitinkevich S S,Mammarella I,Baklanov A A,et al.The effect of stratification on the aerodynamic roughness length and displacement height[J].Boundary Layer Meteorology,2008,129:179-190.
[11]Thom A S.Momentum absorption by vegetation[J].Quarterly Journal of the Royal Meteorological Society,1971,97:414-428.
[12]Zhang Q,Zeng J,Yao T.Interaction of aerodynamic roughness length and windflow conditons and its parameterization over vegetation surface[J].Chinese Science Bulletin,2012,57(13):1559-1567.
[13]谭立海,张伟民,安志山,等.砾石覆盖对边界层风速梯度的影响[J].中国沙漠,2012,32(6):1522-1527.
[14]Xue X,Wang T,Sun Q W,et al.Fiele and wind-tunnel studies of aerodynamic roughness length[J].Boundary Layer Meteorology,2002,104:151-163.
[15]Marshall J K.Drag measurements in roughness arrays of varying density and distribution[J].Agricultural Meteorology,1971,8:269-292.
[16]Wooding R,Bradley E F,Marshall J K.Drag due to regular roughness elements of varying geometry[J].Boundary Layer Meteorology,1973,5:285-308.
[17]Gillies J A,Nickling W G,King J.Shear stress partitioning in large patches of roughness in the atmospheric inertial sublayer[J].Boundary Layer Meteorology,2007,122:367-396.
[18]Bacharov A P.A Description of Devices Used in the Study of Wind Erosion of Soils[M].Boca Raton,USA:CRC Press,1984.
[19]Shao Y.Physics and Modeling of Wind Erosion[M].Berlin,Germany:Springer Science,2008:310-316.
[20]Hatfield J L.Aerodynamic properties of partical canopies[J].Agricultural and Forest Meteorology,1989,46:15-22.
[21]Shinoda M,Gillies J A,Mikami M,et al.Temperate grasslands as a dust source:knowledge uncertainties,and challenges[J].Aeolian Research,2011,3:271-293.
[22]Raupach M R.Drag and drag partition on rough surfaces[J].Boundary Layer Meteorology,1992,60:375-395.
[23]Counihan J.Wind tunnel determination of the roughness length as a function of the fetch and the roughness density of three-dimensional roughness elements[J].Atmospheric Environment,1971,5:637-642.
[24]McKenna Neuman C,Nickling W G.Aeolain sediment flux decay:non-linear behavior on developing deflation lag surfaces[J].Earth Surface Processes Landforms,1995,20:423-432.
[2]Bagnold R A.The Physics of Blown Sand and Desert Dunes[M].New York,USA:Methuen,1941:85-95,265.
[3]李振山,陈广庭.粗糙度研究的现状及展望[J].中国沙漠,1997,17(1):99-102.
[4]刘小平,董治宝.砾石床面的空气动力学粗糙度[J].中国沙漠,2003,23(1):38-45.
[5]Lettau H.Note on aerodynamic roughness-parameter estimation on the basis of roughness-elements description[J].Journal of Applied Meteorology,1969,8:828-832.
[6]薛娴,张伟民,王涛.戈壁砾石防护效应的风洞实验与野外观测结果[J].地理学报,2000,55(3):375-383.
[7]Dong Z B,Liu X P,Wang X M.Aerodynamic roughness of gravel surfaces[J].Geomorphology,2002,43:17-31.
[8]梅凡民,蒋缠文,江姗姗,等.粗糙元几何参数的交互作用对床面空气动力学粗糙度的影响[J].中国沙漠,2012,32(6):1534-1541.
[9]王训明,郎丽丽,花婷,等.戈壁砾石覆盖度与风蚀强度关系实验研究[J].中国沙漠,2013,33(2):313-319.
[10]Zilitinkevich S S,Mammarella I,Baklanov A A,et al.The effect of stratification on the aerodynamic roughness length and displacement height[J].Boundary Layer Meteorology,2008,129:179-190.
[11]Thom A S.Momentum absorption by vegetation[J].Quarterly Journal of the Royal Meteorological Society,1971,97:414-428.
[12]Zhang Q,Zeng J,Yao T.Interaction of aerodynamic roughness length and windflow conditons and its parameterization over vegetation surface[J].Chinese Science Bulletin,2012,57(13):1559-1567.
[13]谭立海,张伟民,安志山,等.砾石覆盖对边界层风速梯度的影响[J].中国沙漠,2012,32(6):1522-1527.
[14]Xue X,Wang T,Sun Q W,et al.Fiele and wind-tunnel studies of aerodynamic roughness length[J].Boundary Layer Meteorology,2002,104:151-163.
[15]Marshall J K.Drag measurements in roughness arrays of varying density and distribution[J].Agricultural Meteorology,1971,8:269-292.
[16]Wooding R,Bradley E F,Marshall J K.Drag due to regular roughness elements of varying geometry[J].Boundary Layer Meteorology,1973,5:285-308.
[17]Gillies J A,Nickling W G,King J.Shear stress partitioning in large patches of roughness in the atmospheric inertial sublayer[J].Boundary Layer Meteorology,2007,122:367-396.
[18]Bacharov A P.A Description of Devices Used in the Study of Wind Erosion of Soils[M].Boca Raton,USA:CRC Press,1984.
[19]Shao Y.Physics and Modeling of Wind Erosion[M].Berlin,Germany:Springer Science,2008:310-316.
[20]Hatfield J L.Aerodynamic properties of partical canopies[J].Agricultural and Forest Meteorology,1989,46:15-22.
[21]Shinoda M,Gillies J A,Mikami M,et al.Temperate grasslands as a dust source:knowledge uncertainties,and challenges[J].Aeolian Research,2011,3:271-293.
[22]Raupach M R.Drag and drag partition on rough surfaces[J].Boundary Layer Meteorology,1992,60:375-395.
[23]Counihan J.Wind tunnel determination of the roughness length as a function of the fetch and the roughness density of three-dimensional roughness elements[J].Atmospheric Environment,1971,5:637-642.
[24]McKenna Neuman C,Nickling W G.Aeolain sediment flux decay:non-linear behavior on developing deflation lag surfaces[J].Earth Surface Processes Landforms,1995,20:423-432.