Dynamics of a nonspherical capsule in general flow
Dynamics of a nonspherical capsule in general flow
复制标题
DOI：
10.1016/j.compfluid.2016.05.011
复制
发表时间：
2016-08
影响因子：
2.8
通讯作者：
Huilin Ye;Haibo Huang;Y. Sui;Xi-yun Lu
中科院分区：
文献类型：
--
作者：
Huilin Ye;Haibo Huang;Y. Sui;Xi-yun Lu
本文用解析和数值方法研究了一般流场中胶囊的动力学。胶囊被建模为一个充满液体的液滴封闭的膜。将Keller-Skalak（KS）理论和Skotheim-Secomb模型应用于一般流动情况，推导了控制方程。结果表明，当粘度比λ= 1时，胶囊动力学受两个无量纲参数的控制，即流体的涡量与应变率之比和弹性力与流体应力之比。在文献中，摆动（SW）和翻滚（TU）之间的过渡总是单向的（TU到SW）。据我们所知，这是第一次发现TU-SW-TU转换，即在某些情况下，转换（TU到SW）发生后，转换也可能从SW转移到TU。可能的机制是流动的旋转抑制了胶囊沿着涡量方向的变形。详细研究了胶囊的形状动力学，并对稀胶囊悬浮液的流变学进行了简要的研究。
The dynamics of a capsule in general flows is studied analytically and numerically. The capsule is modeled as a liquid-filled drop enclosed by a membrane. We adapted the Keller-Skalak (KS) theory and Skotheim-Secomb model to the case of general flow, the governing equations are derived. It is found that when viscosity ratio λ= 1, the capsule dynamics in general flows is controlled by two dimensionless parameters, the ratio of vorticity to strain rate of the flow and the ratio of the elastic force to fluid stress. In the literature, the transition between swinging (SW) and tumbling (TU) is always one way (TU to SW). As far as we know, it is the first time that the TU-SW-TU transition has been identified, ie, the transition may also transfer from SW to TU after the transition (TU to SW) occurs under some circumstances. The possible mechanism is that the rotation of the flow suppresses the deformation along the vorticity direction of the capsule. The shape dynamics of a capsule is studied in detail and the rheology of dilute capsule suspension is also investigated briefly.