北京大学学报(自然科学版) ›› 2015, Vol. 51 ›› Issue (4): 601-605.DOI: 10.13209/j.0479-8023.2015.055

• 研究论文 • 上一篇    下一篇

鸣沙沙粒振动频率自锁机制

林官明1;赵小虎2   

  1. 1. 北京大学环境科学与工程学院, 环境模拟与污染控制国家重点联合实验室, 北京100871; 2. 清华大学环境学院, 北京 100084;
  • 收稿日期:2014-05-08 修回日期:2014-10-11 出版日期:2015-07-20 发布日期:2015-07-20
  • 林官明
  • 基金资助:
    国家自然科学基金(41171005)资助

The Mode Locking of the Booming Sand Dunes

LIN Guanming1;ZHAO Xiaohu2   

  1. 1. State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Science and Engineering, Peking University, Beijing 100871; 2. School of Environment, Tsinghua University, Beijing 100084;
  • Received:2014-05-08 Revised:2014-10-11 Online:2015-07-20 Published:2015-07-20
  • About author:LIN Guanming

摘要: 研究在30°安息角的沙坡面上, 单一粒径球形沙粒的运动状态。假设沙粒无滑动且碰撞时角动量守恒, 则扰动沙粒经过不超过5 次的滚动、抛射、再滚动后,即进入与初条件无关的周期性运动, 其频率为0.39 g/D , 与鸣沙流的梯度相近, 临界抛射角稳定在 51.2°, 抛射过程沙粒自旋角速度为 16 r/min。自保持的周期性决定了沙粒的整体协同运动, 是鸣沙发声及频率自锁的根本原因。

关键词: 鸣沙, 速度梯度, 协同, 角速度

Abstract: A two layer model is developed to investigate the movement of a single round particle. The reference layer is set as a slope with the repose angle 30°, and is covered regularly with round particles with the same diameter. The free layer in which the same diameter can move freely is just on the reference layer. A periodic rolleject- collide movement is found, and the frequency is 0.39 g/D , which is independent of the initial velocity and close to the velocity gradient. The constant projection angle is 51.2° and the spin angular velocity is 16 r/min. This self-hold of frequency determines the sands in the free layer to move forwards integrally, and may be the basic acoustic mechanism of the booming sands.

Key words: booming sands, velocity gradient, self-hold frequency, periodic

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