论文标题
一个简单的捕获：热波动使微卷动器的流体动力诱捕障碍物
A simple catch: thermal fluctuations enable hydrodynamic trapping of microrollers by obstacles
论文作者
论文摘要
众所周知，障碍物可以在轨道中流体动力捕获细菌和合成微晶状体，其中诱捕时间在很大程度上取决于游泳者的流动场和噪声以逃避陷阱。在这里，我们使用实验和仿真来研究微卷动器捕获障碍物的捕获。微型固定器正在旋转靠近底部表面的颗粒，该颗粒具有外部旋转磁场施加的规定推进方向。驱动其运动的流场与先前研究的游泳者完全不同。我们发现，可以通过修改障碍物大小或胶体孔排斥潜力来控制捕获时间。我们详细介绍了捕获的机制，并找到了两个显着的特征：微纤维卷被限制在障碍物之后，并且只能以布朗尼运动进入陷阱。虽然通常需要噪声来逃避动态系统中的陷阱，但在这里，我们表明它是到达流体动力吸引子的唯一手段。
It is known that obstacles can hydrodynamically trap bacteria and synthetic microswimmers in orbits, where the trapping time heavily depends on the swimmer flow field and noise is needed to escape the trap. Here, we use experiments and simulations to investigate the trapping of microrollers by obstacles. Microrollers are rotating particles close to a bottom surface, which have a prescribed propulsion direction imposed by an external rotating magnetic field. The flow field that drives their motion is quite different from previously studied swimmers. We found that the trapping time can be controlled by modifying the obstacle size or the colloid-obstacle repulsive potential. We detail the mechanisms of the trapping and find two remarkable features: The microroller is confined in the wake of the obstacle, and it can only enter the trap with Brownian motion. While noise is usually needed to escape traps in dynamical systems, here, we show that it is the only means to reach the hydrodynamic attractor.
