论文标题
在准2D膜上游泳微生物
Swimming of microorganisms in quasi-2D membranes
论文作者
论文摘要
生物游泳者经常在几何限制的媒体中导航。我们研究了局限于嵌入不同粘度的大量液体中的平面粘性膜的游泳者的处方中风问题。在运动中，微观游泳者会干扰膜和散装中的流体。出现的流量具有二维（2D）和三维（3D）流体动力特征的组合，并且此类流量称为准2D。准2D流体中从2D到3D流体动力学的跨界由Saffman的长度控制，Saffman长度是由2D膜粘度与嵌入式大体流体的3D粘度比给出的长度尺度。我们已经基于边界元素方法和洛伦兹相互定理开发了一种计算和理论方法，以研究微生物的游泳，以范围为Saffman长度值。我们发现，准2D膜中的鞭毛传播横向正弦波可以发展出超过纯的2D或3D流体中的游泳速度，而散装流体的存在使二维蠕动的推进速度减慢了。
Biological swimmers frequently navigate in geometrically restricted media. We study the prescribed-stroke problem of swimmers confined to a planar viscous membrane embedded in a bulk fluid of different viscosity. In their motion, microscopic swimmers disturb the fluid in both the membrane and the bulk. The flows that emerge have a combination of two-dimensional (2D) and three-dimensional (3D) hydrodynamic features, and such flows are referred to as quasi-2D. The cross-over from 2D to 3D hydrodynamics in a quasi-2D fluid is controlled by the Saffman length, a length scale given by the ratio of the 2D membrane viscosity to the 3D viscosity of the embedding bulk fluid. We have developed a computational and theoretical approach based on the boundary element method and the Lorentz reciprocal theorem to study the swimming of microorganisms for a range of values of the Saffman length. We found that a flagellum propagating transverse sinusoidal waves in a quasi-2D membrane can develop a swimming speed exceeding that in pure 2D or 3D fluids, while the propulsion of a two-dimensional squirmer is slowed down by the presence of the bulk fluid.
