Maleki M, Habibi M, Golestanian R, Ribe N M, Bonn Daniel
Institute for Advanced Studies in Basic Sciences, Zanjan 45195-159, Iran.
Phys Rev Lett. 2004 Nov 19;93(21):214502. doi: 10.1103/PhysRevLett.93.214502. Epub 2004 Nov 18.
We present an experimental study of the coiling instability of a liquid "rope" falling on a solid surface. Coiling can occur in three different regimes--viscous, gravitational, or inertial--depending on the fluid viscosity and density, the fall height, and the flow rate. The competition among the different forces causes the coiling frequency first to decrease and subsequently to increase with increasing height. We also observe an oscillation between two coiling states in the gravitational-to-inertial transitional range, reflecting the multivaluedness of the dependence of coiling frequency on fall height. The data can be rescaled in a universal way, and agree very well with numerically predicted coiling frequencies.
我们展示了一项关于液体“绳索”落在固体表面上的盘绕不稳定性的实验研究。根据流体的粘度和密度、下落高度以及流速，盘绕可在三种不同状态下发生——粘性、重力或惯性状态。不同力之间的竞争导致盘绕频率先随高度增加而降低，随后又升高。我们还观察到在重力到惯性的过渡范围内，两种盘绕状态之间存在振荡，这反映了盘绕频率对下落高度的依赖关系具有多值性。这些数据可以通过一种通用方式进行重新标度，并且与数值预测的盘绕频率非常吻合。
