Center for Fluid Mechanics, Brown University, Providence, Rhode Island 02912, USA.
Rev Sci Instrum. 2022 Apr 1;93(4):044103. doi: 10.1063/5.0079815.
Helical propulsion is used by many micro-organisms to swim in viscous-dominated environments. Their swimming dynamics are relatively well understood, but a detailed study of the flow fields is still needed to understand wall effects and hydrodynamic interactions among swimmers. In this letter, we describe the development of an autonomous swimming robot with a helical tail that operates in the Stokes regime. The device uses a battery-based power system with a miniature motor that imposes a rotational speed on a helical tail. The speed, direction, and activation are controlled electronically using an infrared remote control. Since the robot is about 5 cm long, we use highly viscous fluids to match the Reynolds number, Re, to be less than 0.1. Measurements of swimming speeds are conducted for a range of helical wavelengths, λ, head geometries, and rotation rates, ω. We provide comparisons of the experimental measurements with analytical predictions derived from resistive force theory. This force and torque-free neutrally buoyant swimmer mimics the swimming strategy of bacteria more closely than previously used designs and offers a lot of potential for future applications.
螺旋推进被许多微生物用于在粘性主导的环境中游动。它们的游动动力学相对较好理解，但为了了解壁面效应和游动者之间的水动力相互作用，仍需要对流动场进行详细研究。在这封信中，我们描述了一种具有螺旋尾的自主游动机器人的开发，该机器人在 Stokes 区运行。该装置使用基于电池的动力系统和微型电机，微型电机对螺旋尾施加转速。使用红外遥控器通过电子方式控制速度、方向和激活。由于机器人长约 5 厘米，我们使用高粘性流体来匹配雷诺数 Re，使其小于 0.1。我们针对一系列螺旋波长 λ、头部几何形状和旋转率 ω 进行了游泳速度的测量。我们将实验测量结果与基于阻力理论得出的分析预测进行了比较。这种无作用力和转矩的中性浮力游泳者比以前使用的设计更能模拟细菌的游泳策略，并且为未来的应用提供了很大的潜力。
