Edge states control droplet breakup in subcritical extensional flows
Edge states control droplet breakup in subcritical extensional flows
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边缘状态控制亚临界拉伸流中的液滴破碎
DOI：
10.1103/physrevfluids.3.073603
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发表时间：
2018
影响因子：
2.7
通讯作者：
F. Gallaire
中科院分区：
文献类型：
--
作者：
G. Gallino;T. Schneider;F. Gallaire
悬浮在中等强度的拉伸流中的流体液滴可能破碎成碎片，这取决于初始液滴变形的幅度。在亚临界单轴拉伸流中，非破裂基态是线性稳定的，这意味着只有有限振幅的扰动才能触发破裂。因此，稳定基解被其有限吸引域包围。盆地的边界，其特征在于使用边缘跟踪技术，它分离的初始液滴形状返回到非破裂的基础状态，从那些变得不稳定和打破。我们数值构造的边缘状态，一个动态不稳定的平衡，其稳定的流形形成盆地边界。边缘状态平衡控制液滴是否破裂并选择朝向破裂的唯一路径。该路径在物理上对应于公知的端部夹紧机构。因此，我们的结果使实验观察到的动力学合理化[Stone & Leal，J.Fluid Mech.206，223（1989）]。
A fluid droplet suspended in an extensional flow of moderate intensity may break into pieces, depending on the amplitude of the initial droplet deformation. In subcritical uniaxial extensional flow the non-breaking base state is linearly stable, implying that only a finite amplitude perturbation can trigger break-up. Consequently, the stable base solution is surrounded by its finite basin of attraction. The basin boundary, which separates initial droplet shapes returning to the non-breaking base state from those becoming unstable and breaking up, is characterized using edge tracking techniques. We numerically construct the edge state, a dynamically unstable equilibrium whose stable manifold forms the basin boundary. The edge state equilibrium controls if the droplet breaks and selects a unique path towards break-up. This path physically corresponds to the well-known end-pinching mechanism. Our results thereby rationalize the dynamics observed experimentally [Stone & Leal, J. Fluid Mech. 206, 223 (1989)]