| 沙漠与沙漠化 |
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| A Wind Tunnel Simulation on Mean Flow Variances over Transverse Dunes |
QIAN Guang-qiang, DONG Zhi-bao, LUO Wan-yin, WANG Hong-tao
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| Key Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China |
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Abstract In an aeolian dune system, the interactions of dune form, airflow and sediment transport are very complex. The changes of wind velocity induced by dune topography, have an important significant in dune dynamics. In this paper, the variations in the horizontal and vertical velocities over 6 different transverse dune models are investigated in a wind tunnel by applying the particle image velocimetry (PIV). According to the experiment results, in the windward of transverse dunes, the increasing horizontal velocity has a speed-up ratio ranged from 1.28 to 1.89, and the ascending vertical velocity has an upwards direction. Both of the horizontal and vertical velocities run higher with the increasing windward slope. In the lee-side of transverse dunes, the horizontal velocity becomes smaller because of airflow separation, and the velocity value in the separation cell is only 17% of free-stream speed. The vertical velocity has a trend of descending, and the maximum sinking velocity is founded near the flow reattachment point. The velocities in the lee-side of transverse dunes are mainly influenced by the free-stream speed but slightly affected by the stoss slope. The results also show that, the change of velocity is significant in the lower portion near dune surface, the higher from the ground, the slighter influence.
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Received: 26 July 2008
Published: 20 January 2009
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[1]Bagnold R A.The Physics of Blown Sand and Desert Dunes[M].London:Methuen,1941:265.
[2]Sarre R D.Aeolian sand transport[J].Prog Phys Geog，1987，11：157-182.
[3]李振山，倪晋仁.风沙流研究的历史、现状及趋势[J].干旱区资源与环境，1998，12(3)：89-97.
[4]Cooke R U，Warren A，Goudie A.Desert Geomorphology[M].London:UCL Press，1993:526.
[5]Frank A，Kocurek G.Toward a model for airflow on the lee side of aeolian dunes[J].Sedimentology，1996，43(3)：451-458.
[6]吴正.风沙地貌与治沙工程学[M].北京:科学出版社，2003:448.
[7]Lancaster N.Geomorphology of Desert Dunes[M].London:Routledge，1995:290.
[8]李志忠，关有志.纵向沙丘和横向沙丘模拟流场的实验研究[J].中国沙漠，1996，16(4)：360-363.
[9]李恒鹏，陈广庭，李波.新月形沙丘迎风坡气流加速模拟[J].中国沙漠，2001，21(1)：24-27.
[10]哈斯，王贵勇，董光荣.腾格里沙漠东南缘格状沙丘表面气流及其地貌学意义[J].中国沙漠，2000，20(1)：30-34.
[11]哈斯，王贵勇.沙丘背风侧气流的变化特征及其意义[J].地理科学，2000，20(6)：573-576.
[12]Wiggs G F S.Desert dune processes and dynamics[J].Prog Phys Geog，2001，25(1)：53-79.
[13]Walker I J，Nickling W G.Dynamics of secondary airflow and sediment transport over and in the lee of transverse dunes[J].Prog Phys Geog,2002,26(1)：47-75.
[14]Dong Z B，Wang H T，Zhang X H.Height profile of particle concentration in an aeolian saltating cloud:A wind tunnel investigation by PIV MSD[J].Geophysical Research Letters，2004，30(19)：12.1-12.4.
[15]钱广强,董治宝,王洪涛，等.粒子图像测速(PIV) 技术在风沙环境风洞中的应用[J].中国沙漠，2006，26(6)：890-893.
[16]Mason P J，Sykes R I.Flow over an isolated hill of moderate slope[J].Quart J R Met Soc，1979，105：383-395.
[17]Howard A D,Morton J B,Gad\|el\|Hak M，et al.Sand transport model of barchan dune equilibrium[J].Sedimentology，1978，25：307-338.
[18]Lancaster N.Variations in wind velocity and sand transport on the windward flanks of desert sand dunes[J].Sedimentology，1985，32：581-593.
[19]Mulligan K R.Velocity profiles measured on the windward slope of a transverse dune[J].Earth Surf Proc Landf，1988，13：573-582.
[20]Lancaster N.The role of field experiments in studies of dune dynamics and morphology[J].Ann Arid Zone，1996，35(3)：171-186.
[21]McKenna\|Neuman C，Lancaster N，Nickling W G.Ralations between dune morphology,air flow,and sediment flux on reversing dunes,Silver Peak,Nevada[J].Sedimentology，1997，44：1103-1113.
[22]Frank A J，Kocurek G.Airflow up the stoss slope of sand dunes:Limitations of current understanding[J].Geomorphology，1996，17(1-3)：47-54.
[23]Sweet M L，Kocurek G.An empirical model eolian dune lee\|face flow[J].Sedimentology，1990，37：1023-1038.
[24]Wiggs G F S，Livingstone I，Warren A.The role of streamline curvature in sand dune dynamics:Evidence from field and wind tunnel measurements[J].Geomorphology，1996，17：29-46.
[25]Walker I J.Secondary airflow and sediment transport in the lee of transverse dunes[D].The University of Guelph，2000:257.
[26]刘贤万.颗粒运动及其数理简析[J].中国沙漠，1993，13(2)：1-8.
[27]杨保.气流中颗粒阻力系数和升力系数讨论[J].中国沙漠，1998，18(1)：70-76. |
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2009, Vol. 29 
