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0.39g/D(1/2),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。
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（1/2）, 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.
出处
《北京大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2015年第4期601-605,共5页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
国家自然科学基金(41171005)资助
关键词
鸣沙
速度梯度
协同
角速度
booming sands
velocity gradient
self-hold frequency
periodic
