论文标题
连接到两个移动液滴的粘弹性液体丝的动力学
Dynamics of a viscoelastic liquid filament connected to two mobile droplets
论文作者
论文摘要
液体的细丝通常不稳定，并分解成小液滴，而聚合物溶液的细丝在这种不稳定性方面非常稳定，并且它们形成了连接两个球形液滴的细丝的稳定构型。如果液滴固定在太空中，则液体将从细丝区域流向液滴区域，以减少表面能，并且丝变细。如果将整个液体放在另一种粘性液中，则液滴彼此接近，并且丝可能会变厚。在这里，我们研究了这种系统的动力学。考虑到从细丝到液滴的流体通量和液滴运动的流体通量，我们得出了半径和长度的时间演化方程。我们将证明（a）液滴的中心是固定的，如果经典预测Entov和Hinch的经典预测后的细丝薄片，并且（b）如果液滴是移动的（在粘性培养基中拖动的stokes拖动），则丝状的稀疏被抑制，并且在某些条件下，丝状会变厚。该理论解释了Yang和Xu [Phys。流体20，043101（2008）]在四辊磨机设备中。
A filament of liquid is usually unstable and breaks up into small droplets, while a filament of polymer solution is known to be quite stable against such instability, and they form a stable configuration of filament connecting two spherical droplets. If the droplets are fixed in space, the liquid flows from the filament region to the droplet region to reduce the surface energy and the filament gets thinner. If the whole liquid is placed in another viscous fluid, the droplets approach each other, and the filament can get thicker. Here we study the dynamics of such system. We derive time evolution equations for the radius and the length of the filament taking into account the fluid flux from filament to droplets and the motion of the droplets. We will show that (a) if the centers of the droplets are fixed, the filament thins following the classical prediction of Entov and Hinch, and that (b) if the droplets are mobile (subject to the Stokes drag in the viscous medium), the thinning of the filament is suppressed, and under certain conditions, the filament thickens. This theory explains the phenomena observed by Yang and Xu [Phys. Fluids 20, 043101 (2008)] in four-roller mill device.
