地理学报 ›› 1998, Vol. 53 ›› Issue (6): 520-527.doi: 10.11821/xb199806005

• 论文 • 上一篇    下一篇

风成沙纹形成的风洞模拟研究

凌裕泉1, 刘绍中2, 吴正3, 李长治1   

  1. 1. 中国科学院兰州沙漠研究所,兰州730000;
    2. 中国科学院成都计算机应用研究所,成都610041;
    3. 华南师范大学地理系,广州510631
  • 收稿日期:1996-09-01 修回日期:1997-07-01 出版日期:1998-11-15 发布日期:1998-11-15
  • 基金资助:
    国家自然科学基金,编号49371009

A WIND TUNNEL SIMULATION OF AEOLIAN SAND RIPPLE FORMATION

Ling Yuquan1, L iu Shaozhong2, Wu Zheng3, Li Changzhi1   

  1. 1. Institute of Desert Research, Chinese Academy of Sciences, Lanzhou 730000;
    2. Institute of Computer Application, Chinese Academy of Sciences, Chengdu 610041;
    3. Department of Geography, South China Normal University, Guangzhou 510631
  • Received:1996-09-01 Revised:1997-07-01 Online:1998-11-15 Published:1998-11-15
  • Supported by:
    Supported by National Natural Science Foundation of China

摘要: 风成沙纹形成于沙质床面下游的沙粒蠕移,发展于沙粒跃移-风沙流的“波粒二重性”作用,消亡于气流与风沙流的正弦波共振。以细沙和极细沙为优势粒级的天然沙丘沙是风成沙纹形成的最佳粒配。沙纹移动速度VR是缓慢的,其数量级为10-1cm·min-1~101cm·min--1,实验关系式为:VR=1.58×(VL-5.5)0.67.

关键词: 风成沙纹, 波粒二重性, 正弦波共振

Abstract: Aeolian sand ripples are a common landform feature created by the movement of sand grains on sand bed driven by wind. The process of their formation and evolution are complex. Although there are no apparent stages in the evolutionary process, which depend essentially on the changing conditions of the wind, three rough stages are suggested by our wind funnel experiment. The first is the stage of formation, during which sand ripples are formed by sand grains creeping forward on the sand bed. Sand grain creeping requires time and involves the adjustment of position of the grains on the sand bed, i.e., sand grains are sorted out by wind. During this stage, the sand driving wind is a state of nonsaturation in which the air currents fluctuate and the grains creep. Sand ripples do not follow any typical pattern and their distribution is random. The second is the stage of development. Sand ripples develop due of the action of wave grain duality. During two stage, sand driving wind is highly satuated and a state of balance is reached between sand grain creep and the intensity of grain saltation. The wave grain duality of the sand driving wind also reaches maximum, as does the action of grain sorting by wind. Third, during the stage of disappearance, high unsaturated sand driving wind hastens the processes of the sand ripple morphological changes, disintegrate the sand ripples, and reconstitute them. Creeping is rapidly changing into soltation. These processes cause sine wave resonance between air current and sand driving wind until the sand ripples disappear. Fine sand and extremely fine sand of natural sand dunes are the grain sizes for the formation of sand ripples. The major forms of sand ripples include the wave form which is the most basic and recurrent, the abnormal forms and their derivations, all nourecurring; and the crescent form found in the border zone between the coarse and fine sand beds. The velocity of sand ripple movement is slow, raging between 10 -1 ~10 1 cm/min. The experiment formula is VR=1.58×(VL-5.5)0.67(cm/min). The wave length and wave height of the sand ripples in the experiment are identical to those found in the field.

Key words: aeolian sand ripples, wave grain duality, sine wave resonance

中图分类号: 

  • P512.21