Jain Utkarsh, Jalaal Maziyar, Lohse Detlef, van der Meer Devaraj
Physics of Fluids Group and Max Planck Center Twente for Complex Fluid Dynamics, MESA+ Institute and J. M. Burgers Centre for Fluid Dynamics, University of Twente, P.O. Box 217, 7500AE Enschede, The Netherlands.
Soft Matter. 2019 Jun 12;15(23):4629-4638. doi: 10.1039/c9sm00318e.
We experimentally study the impacts of viscous, immiscible oil drops into a deep pool of water. Within the target liquid pool, the impacting drop creates a crater, whose dynamics are studied. It is found that the inertia of pool liquid and drop viscosity are the main factors that determine the crater's maximum depth, while the additional factor of mutual immiscibility between the drop and pool liquids leads to interesting interfacial dynamics along the oil-water interface. We discuss how this can change the crater dynamics in its retraction phase, making possible a type of double-entrainment, whereby a tiny air bubble is entrapped inside a water-entrained oil drop. Further, we report the observation of a type of 'fingering' that occurs along the oil-drop rim, which we discuss, arises as a remnant of the well-known crown-splash instability.
我们通过实验研究了粘性、不混溶的油滴落入深水池中的影响。在目标液体池中，撞击的油滴会形成一个坑，我们对其动力学进行了研究。结果发现，池液的惯性和油滴粘度是决定坑最大深度的主要因素，而油滴与池液之间互不相溶这一额外因素会导致油水界面处有趣的界面动力学。我们讨论了这如何在坑的回缩阶段改变坑的动力学，使得一种双重夹带成为可能，即一个微小的气泡被困在一个夹带水的油滴内部。此外，我们报告了沿油滴边缘出现的一种“指进”现象的观察结果，我们认为这种现象是著名的冠形飞溅不稳定性的残余。
