Peristaltic transport of inelastic circular droplets immersed in an immiscible viscous fluid is numerically studied in a planar two-dimensional channel using the finite-volume method. Numerical results could be obtained for a wide range of droplet’s material properties at large deformations. Based on the results obtained in this work, for a particle that is initially placed at the centerline, an increase in the droplet’s viscosity is predicted to increase its transport velocity, but the effect can saturate at viscosity ratios as small as two. The transport velocity is shown to linearly increase with the droplet’s density, but the effect turns out to be quite weak. An increase in the interfacial tension is found to lower the transport velocity although the effect appears to approach an asymptote. Depending on their size and the Weber number, droplets are predicted to move faster or slower than rigid particles. The transport velocity of droplets is found to increase with an increase in the wave speed or, equivalently, the Reynolds number. Off-center droplets are predicted to migrate toward the wall or toward the centerline. Droplets that migrate toward the centerline remain a short distance away from it under steady conditions. Distribution of surface forces is used to explain some of these results with viscous normal stress predicted to play a key role in controlling the dynamics of droplets in peristaltic flow.

中文翻译：

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使用蠕动波传输软粒子：数值研究

使用有限体积方法在平面二维通道中对浸入不混溶粘性流体中的非弹性圆形液滴的蠕动传输进行了数值研究。可以在大变形下获得各种液滴材料特性的数值结果。基于在这项工作中获得的结果，对于最初放置在中心线的粒子，预计液滴粘度的增加会增加其传输速度，但这种效果可以在粘度比低至 2 时达到饱和。传输速度显示为随液滴密度线性增加，但效果非常微弱。发现界面张力的增加会降低传输速度，尽管这种效果似乎接近渐近线。根据它们的大小和韦伯数，预计液滴比刚性粒子移动得更快或更慢。发现液滴的传输速度随着波速或雷诺数的增加而增加。预计偏离中心的液滴会向壁或中心线迁移。在稳定条件下，向中心线迁移的液滴与中心线保持一小段距离。表面力的分布用于解释其中一些结果，其中粘性法向应力预计在控制蠕动流中液滴的动力学方面起关键作用。预计偏离中心的液滴会向壁或中心线迁移。在稳定条件下，向中心线迁移的液滴与中心线保持一小段距离。表面力的分布用于解释其中一些结果，其中粘性法向应力预计在控制蠕动流中液滴的动力学方面起关键作用。预计偏离中心的液滴会向壁或中心线迁移。在稳定条件下，向中心线迁移的液滴与中心线保持一小段距离。表面力的分布用于解释其中一些结果，其中粘性法向应力预计在控制蠕动流中液滴的动力学方面起关键作用。