二维沙丘迎风坡沙粒跃移运动的数值模拟

doi:10.7522/j.issn.1000-694X.2013.00274

摘要/Abstract

摘要： 为了研究沙丘迎风坡面上沙粒的跃移运动，本文根据风工程和空气动力学的最新理论，给出了沙丘迎风坡面上风场的空间分布规律，在此基础上对沙粒跃移运动进行了数值计算。由于沙丘周围流场情况较为复杂，各处的风速廓线也不同，故选取不同的坡面位置进行跃移计算，其中各处的起沙率由已有的实验结果或拟合公式给出。计算结果表明：从坡脚到坡顶，平均风速加速比和摩阻风速逐渐增加，到沙丘顶部达到最大值；同时沿坡面向上，各截面处单宽输沙率和距离当地地面相同高度处输沙浓度逐渐加强，这与已有文献报道的结果吻合良好。

关键词: 加速因子, 迎风坡, 单宽输沙率, 输沙浓度

Abstract: A new model is presented for calculating sand saltation on the windward side of two-dimensional dune. First, the wind profile is established by using the wind engineering and aerodynamics achievements, then the saltation of sand grains in a turbulent air flow is simulated by employing particle trajectory method. Since the wind field on the dune is quite complicated, and the wind profiles are different along the windward side of the dune, some typical positions are selected for numerical simulation. The surface ejection flux as initial condition in calculation is obtained by field measurement or empirical relationship with local friction velocity in literature. The numerical results show that the mean wind speed increases from the foot to the top of dune and reaches its maximum speed-up ratio at the dune top, the simulated sand transport rate and the mass flux profile are in good accordance with results reported in literature.

Key words: speed-up ratio, windward side of dune, sand transport rate, mass flux profile

中图分类号:

O359

武生智, 郭为进. 二维沙丘迎风坡沙粒跃移运动的数值模拟[J]. 中国沙漠, 2014, 34(2): 307-311.

Wu Shengzhi, Guo Weijin. Numerical Simulation of Saltation on the Windward Side of Sand Dunes[J]. JOURNAL OF DESERT RESEARCH, 2014, 34(2): 307-311.

参考文献

[1] Owen P R.The saltation of uniform sand in air[J].Journal of Fluid Mechanics,1964,20:225-242.
[2] White B R,Sehulz J C.Magnus effect in saltation[J].Journal of Fluid Mechanics,1977,81:497-512.
[3] Ungar J E,Haff P K.Steady state saltation in air[J].Sedimentology,1987,34:289-299.
[4] Zheng X J,Huang N,Zhou Y.The effect of electrostatic force on the evolution of sand[J].The European Physical Journal E,2006,19:129-138.
[5] Iverson J D,Raumussen K R.The effect of wind speed and bed slope on sand transport[J].Sedimentology,1999,46:723-731.
[6] White B R,Tsoar H.Slope effect on saltation over a climbing sand dune[J].Geomorphology,1998,22:159-180.
[7] 蒋红,佟鼎,黄宁.坡面风沙运动的风洞实验及数值模拟[J].工程力学,2011,28(12):190-198.
[8] Sauermann G,Andrade Jr J S,Maia L P,et al.Wind velocity and sand transport on a barchan dune[J].Geomorphology,2003,54:245-255.
[9] 李建国,屈建军,李芳,等.不同类型防沙堤流场的风洞实验模拟研究[J].中国沙漠,2012,32(2):291-299.
[10] 李得禄,满多清,朱国庆,等.丘间低地不同部位风沙流结构特征[J].中国沙漠,2012,32(5):1210-1215.
[11] 李双权,哈斯,杜会石,等.沙质草地碟形风蚀坑形态气流相互作用[J].中国沙漠,2012,32(5):1201-1209.
[12] Jackson P S,Hunt J C R.Turbulent wind flow over a low hill[J].Quarterly Journal of the Royal Meteorological Society,1975,101:929-955.
[13] Kaimal J,Finnigan J.Atmospheric Boundary Layer Flows－Their Structure and Measurement[M].Oxford,UK:Oxford University Press,1994.
[14] Lemelin D R,Surry D,Davenport A G.Simple approximations for wind speed-up over hills[J].Journal of Wind Engineering and Industrial Aerodynamics,1988,28:117-127.
[15] Taylor P A,Lee R J.Simple guidelines for estimating wind speed variations due to small scale topographic features[J].Climatological Bulletin,1984,18(2):3-22.
[16] 李晖.风沙流的实验研究和蠕移运动的非线性动力分析[D].兰州:兰州大学,2009.
[17] Anderson R S,Hallet B.Sediment transport by wind:toward a general mode[J].Geological Society of America Bulletin,1986,97:523-535.