A boundary-integral model for drop deformation between two parallel plates with non-unit viscosity ratio drops
A boundary-integral model for drop deformation between two parallel plates with non-unit viscosity ratio drops
复制标题
非单位粘度比液滴两平行板间液滴变形的边界积分模型
DOI：
10.1016/j.jcp.2008.06.027
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
P. D. Anderson
中科院分区：
文献类型：
--
作者：
P. Janssen;P. D. Anderson
针对非单位粘度比体系，提出了两平行壁间液滴变形的边界积分法。为了考虑墙的影响，对格林函数进行了修正，并导出了双层势的所有项。对全三维实现进行了验证，结果表明该模型具有较高的精度和一致性。将该方法应用于剪切流中液滴变形的研究。在低毛细管数下，我们发现与小变形理论有很好的匹配，并且我们的结果与其他压力驱动流动的BIM模拟结果相吻合。对于中等毛细管数的剪切流动，我们看到低粘度液滴的行为类似于粘度比为1的液滴。另一方面，高粘度的液滴在剪切流中不会旋转，从而导致较大的变形，但液滴轴线的超调较小。与非受限流动相比，高粘度液滴在平行板之间的剪切流动中可以破碎；对于低粘度液滴，在受限情况下临界毛细管数较高。
A boundary-integral method is presented for drop deformation between two parallel walls for non-unit viscosity ratio systems. To account for the effect of the walls the Green’s functions are modified and all terms for the double-layer potential are derived. The full three-dimensional implementation is validated, and the model is shown to be accurate and consistent. The method is applied to study drop deformation in shear flow. An excellent match with small-deformation theory is found at low capillary numbers, and our results match with other BIM simulations for pressure-driven flows. For shear flow with moderate capillary numbers, we see that the behavior of a low-viscosity drop is similar to that of drop with a viscosity ratio of unity. High-viscosity drops, on the other hand, are prevented from rotating in shear flow, which results in a larger deformation, but less overshoot in the drop axes is observed. In contrast with unconfined flow, high-viscosity drops can be broken in shear flow between parallel plates; for low-viscosity drops the critical capillary number is higher in confined situations.