竖直振动振子振动频率对所产生表面水波流向影响的研究  

The Study of the Effect of Oscillation Frequency of Vertical Oscillator on the Flow Direction of Surface Water Wave

作　　者：尹梦迪 林伟华[1] 

机构地区：[1]武汉大学物理科学与技术学院物理国家级实验教学示范中心(武汉大学),湖北武汉430072

出　　处：《科技视界》2017年第26期1-4,共4页Science & Technology Vision

基　　金：教育部高等学校物理学类专业教学指导委员会教改项目(NO.01-201601-39);武汉大学2016年教学研究项目(NO.24);武汉大学2016年开放实验项目;国家自然科学基金面上项目(NO.61575145)

摘　　要：观察一在水中半浸没的竖直振动水平圆柱周围的水波,圆柱的振动频率对其周围水波流向有明显影响。在低频率时,平面波自振子向周围推进;增加频率,交叉波逐渐取代平面波,在振子周围形成不稳定流场;继续增加频率,振子周围形成拉格朗日相干结构,并满足Lighthill判据,继而发生水波逆向流动现象。实验通过改变振动频率、幅度及振子材质观察水波流动现象,来探究水波逆向流动的因素,并尝试用流形解释这一现象。通过振动驱动水波流向改变,这一非线性动力学现象,可在日后的水运中得到应用,达到节能、高效生产的目的。Observing the surface water wave generated by a half-submerged vertically oscillating cylinder, the frequency of oscillation would have great influence on the propagating direction of the flow. When the cylinder is vibrating with a low frequency, the waves are observed escaping from the cylinder as plane waves. As the frequency is increased, cross-waves appear and the field around the object becomes unstable. When the frequency is high enough,Lagrangian Coherent Structures is formed around the cylinder and Lighthill criterion is satisfied, as well as the propagating direction of waves reversed. The influence effectors of the reversed flow are experimentally studied by changing the oscillating frequency and amplitude of the oscillators, as well as the materials. What ＇ s more, the effectors could be explained using manifold. The method of changing the propagating direction of water flow by oscillations, a nonlinear dynamic phenomenon, could be applied in water carriage in the future with more energy conservation and higher efficiency.

关 键 词：竖直振动 表面水波流向 拉格朗日相干结构 Lighthill判据 流形 

分 类 号：G649.28[文化科学—高等教育学]