Bailey A G, Lowe C P, Pagonabarraga I, Lagomarsino M Cosentino
Department of Physics, Imperial College London, London, United Kingdom.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Oct;80(4 Pt 2):046707. doi: 10.1103/PhysRevE.80.046707. Epub 2009 Oct 28.
Microscopic semiflexible filaments suspended in a viscous fluid are widely encountered in biophysical problems. The classic example is the flagella used by microorganisms to generate propulsion. Simulating the dynamics of these filaments numerically is complicated because of the coupling between the motion of the filament and that of the surrounding fluid. An attractive idea is to simplify this coupling by modeling the fluid motion by using Stokeslets distributed at equal intervals along the model filament. We show that, with an appropriate choice of the hydrodynamic radii, one can recover accurate hydrodynamic behavior of a filament with a finite cross section without requiring an explicit surface. This is true, however, only if the hydrodynamic radii take specific values and that they differ in the parallel and perpendicular directions leading to a caterpillarlike hydrodynamic shape. Having demonstrated this, we use the model to compare with analytic theory of filament deformation and rotation in the small deformation limit. Generalization of the methodology, including application to simulations using the Rotne-Prager tensor, is discussed.
悬浮在粘性流体中的微观半柔性细丝在生物物理问题中广泛存在。经典的例子是微生物用于产生推进力的鞭毛。由于细丝运动与周围流体运动之间的耦合，对这些细丝的动力学进行数值模拟很复杂。一个有吸引力的想法是通过使用沿模型细丝等间隔分布的斯托克斯子来对流体运动进行建模，从而简化这种耦合。我们表明，通过适当选择流体动力学半径，无需明确表面就能恢复具有有限横截面的细丝的准确流体动力学行为。然而，只有当流体动力学半径取特定值且它们在平行和垂直方向上不同，从而导致类似毛虫的流体动力学形状时，才会如此。证明这一点后，我们使用该模型与小变形极限下细丝变形和旋转的解析理论进行比较。还讨论了该方法的推广，包括应用于使用罗特内 - 普拉格张量的模拟。
