State diagram of a three-sphere microswimmer in a channel
State diagram of a three-sphere microswimmer in a channel
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DOI：
10.1088/1361-648x/aac470
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发表时间：
2018-03
期刊：
影响因子：
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通讯作者：
Abdallah Daddi-Moussa-Ider;M. Lisicki;A. Mathijssen;Christian Hoell;Segun Goh;J. Blawzdziewicz;A. Menzel;H. Löwen
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文献类型：
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作者：
Abdallah Daddi-Moussa-Ider;M. Lisicki;A. Mathijssen;Christian Hoell;Segun Goh;J. Blawzdziewicz;A. Menzel;H. Löwen
几何限制在软物质系统中经常遇到，特别是显着改变粘性介质中游动微生物的动力学。微型游泳器运动的表面相关影响可能会在大量生物系统中产生重要后果，例如生物膜形成、细菌粘附和微生物活动。在低雷诺数流体动力学的基础上，我们探索了狭缝几何形状的通道限制下三球微型游泳器的状态图，并充分表征了中性游泳者、拉式和推式游泳者的游泳行为和轨迹。虽然推动者总是被困在通道壁上，但中立的游泳者和拉动者可以进一步执行滑行运动并保持沿着通道的稳定导航。我们发现，由此产生的动力系统表现出超临界干草叉分叉，其中在中间平面中的游动在超过过渡通道高度时变得不稳定，同时出现两个新的稳定极限环或相对于通道中间高度对称设置的固定点。此外，我们还表明，只要游泳者的尺寸远小于通道高度，就可以使用流体动力学图像的方法来分析捕获通道中平均游泳速度和旋转速率的准确描述。
Geometric confinements are frequently encountered in soft matter systems and in particular significantly alter the dynamics of swimming microorganisms in viscous media. Surface-related effects on the motility of microswimmers can lead to important consequences in a large number of biological systems, such as biofilm formation, bacterial adhesion and microbial activity. On the basis of low-Reynolds-number hydrodynamics, we explore the state diagram of a three-sphere microswimmer under channel confinement in a slit geometry and fully characterize the swimming behavior and trajectories for neutral swimmers, puller- and pusher-type swimmers. While pushers always end up trapped at the channel walls, neutral swimmers and pullers may further perform a gliding motion and maintain a stable navigation along the channel. We find that the resulting dynamical system exhibits a supercritical pitchfork bifurcation in which swimming in the mid-plane becomes unstable beyond a transition channel height while two new stable limit cycles or fixed points that are symmetrically disposed with respect to the channel mid-height emerge. Additionally, we show that an accurate description of the averaged swimming velocity and rotation rate in a channel can be captured analytically using the method of hydrodynamic images, provided that the swimmer size is much smaller than the channel height.