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中国沙漠 ›› 2001, Vol. 21 ›› Issue (1): 24-27.

• 研究论文 • 上一篇    下一篇

新月形沙丘迎风坡气流加速模拟

李恒鹏1, 陈广庭2, 李波1   

  1. 1. 中国科学院南京地理与湖泊研究所, 江苏南京 210008;
    2. 中国科学院寒区旱区环境与工程研究所, 甘肃兰州 730000
  • 收稿日期:2000-03-15 修回日期:2000-05-29 出版日期:2001-03-20 发布日期:2001-03-20
  • 作者简介:李恒鹏(1973-),男(汉族),山西省浑源县人,博士生,主要从事风沙地貌和海岸环境研究。

Simulation of Flow Accelerating on the Windward of Barchan

LI Heng-peng1, CHEN Guang-ting2, LI Bo1   

  1. 1. Nanjin Institute of Geography and Liminology Research, Chinese Academy of Sciences, Nanjin 210008, China;
    2. Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou 730000, China
  • Received:2000-03-15 Revised:2000-05-29 Online:2001-03-20 Published:2001-03-20

摘要: 迎风坡气流加速是决定新月形沙丘发育和形态的动力因子,研究这一加速过程的定量关系有利于认识沙丘的发育、沙丘的形态、沙丘的运动等。通过大量的野外实测数据和前人的理论分析,得出沙丘迎风坡气流加速量主要和沙丘坡度、迎风坡前来流风速以及沙丘高度有关,并建立了新月形沙丘迎风坡气流加速和沙丘形态特征的定量关系。根据这一关系得出在风力较强的风沙环境中,沙丘坡度较小;在风力较弱的风沙环境中,沙丘坡度较陡。地表粗糙度越大,迎风坡坡度越陡。沙丘地貌发育高度存在一上限,这一上限与边界层厚度有关。

关键词: 新月形沙丘, 迎风坡, 加速模拟, 沙丘形态

Abstract: Velocity speeding-up on the windward flanks of barchans is a dynamic factor which control dune formation and dune shape. This research provides further understanding to the formation, the shape and the movement of dunes. At present, there are lots of documents which report the result of studies about the relationship between dynamic process and dune shape, including field studies, wind tunnel studies and numerical simulation. These studies are mainly about the relationship between velocity speed-up on the windward flanks of barchans and the height of the dune. However, the degree of slope, which is very important, hasn't been considered. This paper, based on the observations of wind velocity in Taklimakan desert and theoretical analysis, studies the quantitative relationship between velocity speed-up, wind velocity, dune slope and dune height. According to the result of the simulation, the amount of speeding-up on the windward flank is about as 1.3~2 times as the beginning. The velocity speed-up is postively correlative with the height of dune and the degree of windward slope and negatively correlative with the velocity of the coming wind. In addition, with the heightening of dune, the velocity of wind on the windward flank has trend of stability. The relationship suggests that dunes tend to develop steeper profiles at rather low wind velocity environment than at high wind velocity environment. On the rough surface the dune windward flank is steeper than on the smooth surface. There is a limited height to all the dunes, which was determined by the depth of the boundary layer.

Key words: barchan, windward flank, wind speed-up simulation, dune shape

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