Institute of Theoretical Physics, Technische Universität Berlin, 10623 Berlin, Germany.
Soft Matter. 2021 Dec 22;18(1):48-52. doi: 10.1039/d1sm01339d.
The current work studies the dynamics of a microswimmer in pressure-driven flow of a weakly viscoelastic fluid. Employing a second-order fluid model, we show that a self-propelling swimmer experiences a viscoelastic swimming lift in addition to the well-known passive lift that arises from its resistance to shear flow. Using the reciprocal theorem, we evaluate analytical expressions for the swimming lift experienced by neutral and pusher/puller-type swimmers and show that they depend on the hydrodynamic signature associated with the swimming mechanism. We find that, in comparison to passive particles, the focusing of neutral swimmers towards the centerline can be significantly accelerated, while for force-dipole swimmers no net modification in cross-streamline migration occurs.
目前的工作研究了微游泳者在弱粘弹性流体的压力驱动流中的动力学。通过采用二阶流体模型，我们表明，自推进游泳者除了由于其对剪切流的阻力而产生的众所周知的被动升力之外，还会经历粘弹性游泳升力。利用互易定理，我们评估了中性和推/拉型游泳者所经历的游泳升力的解析表达式，并表明它们取决于与游泳机制相关的水动力特征。我们发现，与被动粒子相比，中性游泳者向中心线的聚焦可以显著加速，而对于力偶游泳者，横流迁移不会发生净修改。
