Motion of an active bent rod with an articulating hinge: exploring mechanical and chemical modes of swimming
Motion of an active bent rod with an articulating hinge: exploring mechanical and chemical modes of swimming
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DOI：
10.3389/fphy.2023.1307691
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发表时间：
2023-12
影响因子：
3.1
通讯作者：
Ritu R. Raj;Arkava Ganguly;Cora Becker;C. W. Shields;Ankur Gupta
中科院分区：
文献类型：
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作者：
Ritu R. Raj;Arkava Ganguly;Cora Becker;C. W. Shields;Ankur Gupta
在微尺度下游泳通常涉及两种运动模式：机械推进和由于场相互作用的推进。在机械推进过程中，粒子通过重新配置它们的几何形状来游动。当由场相互作用推动时，诸如泳动相互作用的体力驱动移动性。在这项工作中，我们采用细长体理论来探讨如何弯曲杆致动器推进由于游泳通过铰链关节的机械模式，并由于通过与溶质场的扩散泳相互作用的化学模式的游泳。虽然以前的理论研究已经研究了机械和化学模式的游泳隔离，这两种模式的同时调查仍然是未开发的。对于机械模式的游泳，我们的计算，数值和分析，恢复珀塞尔的扇贝定理，并表明，弯曲杆致动器经历零净位移在往复运动。此外，我们计算的轨迹跟踪下的非往复铰链关节弯曲杆致动器，揭示这些轨迹的铰链关节的振幅，几何不对称性，和弯曲杆致动器的两臂之间的角速度分布的影响。我们提供直观的解释，这些影响使用自由体图。此外，我们探讨了同时铰链关节和自扩散电泳引起的运动。我们观察到，铰链关节可以修改有效的电泳力和扭矩作用在弯曲杆致动器，无论是支持或阻碍推进。此外，在自扩散电泳推进过程中，相互铰链关节不再导致零净位移。总之，我们的研究结果为设计微米尺寸的物体指明了新的方向，这些物体同时利用机械和化学推进模式，提供了一种控制轨迹的机制。
Swimming at the microscale typically involves two modes of motion: mechanical propulsion and propulsion due to field interactions. During mechanical propulsion, particles swim by reconfiguring their geometry. When propelled by field interactions, body forces such as phoretic interactions drive mobility. In this work, we employ slender-body theory to explore how a bent rod actuator propels due to a mechanical mode of swimming via hinge articulations and due to a chemical mode of swimming via diffusiophoretic interactions with a solute field. Although previous theoretical studies have examined mechanical and chemical modes of swimming in isolation, the simultaneous investigation of both modes has remained unexplored. For the mechanical mode of swimming, our calculations, both numerical and analytical, recover Purcell’s scallop theorem and show that the bent rod actuator experiences zero net displacement during reciprocal motion. Additionally, we calculate the trajectories traced by a bent rod actuator under a non-reciprocal hinge articulation, revealing that these trajectories are influenced by the amplitude of the hinge articulation, geometric asymmetry, and the angular velocity distribution between the two arms of the bent rod actuator. We provide intuitive explanations for these effects using free-body diagrams. Furthermore, we explore the motion induced by simultaneous hinge articulations and self-diffusiophoresis. We observe that hinge articulations can modify the effective phoretic forces and torques acting on the bent rod actuator, either supporting or impeding propulsion. Additionally, during self-diffusiophoretic propulsion, reciprocal hinge articulations no longer result in zero net displacement. In summary, our findings chart a new direction for designing micron-sized objects that harness both mechanical and chemical modes of propulsion synchronously, offering a mechanism to enact control over trajectories.