Pimponi Daniela, Chinappi Mauro, Gualtieri Paolo
Dipartimento di Ingegneria Meccanica e Aerospaziale, Sapienza Università di Roma, via Eudossiana 18, 00184, Roma, Italy.
Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, via del Politecnico 1, 00133, Roma, Italy.
Eur Phys J E Soft Matter. 2018 Feb 28;41(2):28. doi: 10.1140/epje/i2018-11635-6.
The hydrodynamics of a flagellated microswimmer moving in thin films is discussed. The fully resolved hydrodynamics is exploited by solving the Stokes equations for the actual geometry of the swimmer. Two different interfaces are used to confine the swimmer: a bottom solid wall and a top air-liquid interface, as appropriate for a thin film. The swimmer follows curved clockwise trajectories that can converge towards an asymptotically stable circular path or can result in a collision with one of the two interfaces. A bias towards the air-liquid interface emerges. Slight changes in the swimmer geometry and film thickness strongly affect the resulting dynamics suggesting that a very reach phenomenology occurs in the presence of confinement. Under specific conditions, the swimmer follows a "crown-like" path. Implications for the motion of bacteria close to an air bubble moving in a microchannel are discussed.
讨论了在薄膜中运动的鞭毛微型游动体的流体动力学。通过求解针对游动体实际几何形状的斯托克斯方程，利用了完全解析的流体动力学。使用两种不同的界面来限制游动体：底部固体壁和顶部气液界面，这适用于薄膜。游动体遵循顺时针弯曲轨迹，这些轨迹可以汇聚到渐近稳定的圆形路径，或者可能导致与两个界面之一发生碰撞。出现了朝向气液界面的偏向。游动体几何形状和薄膜厚度的微小变化会强烈影响所产生的动力学，这表明在存在限制的情况下会出现非常丰富的现象学。在特定条件下，游动体遵循“冠状”路径。讨论了对在微通道中移动的气泡附近细菌运动的影响。
