Theers Mario, Winkler Roland G
Theoretical Soft Matter and Biophysics, Institute for Advanced Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Soft Matter. 2014 Aug 28;10(32):5894-904. doi: 10.1039/c4sm00770k.
We investigate the emergent dynamical behavior of hydrodynamically coupled microrotors by means of multiparticle collision dynamics (MPC) simulations. The two rotors are confined in a plane and move along circles driven by active forces. Comparing simulations to theoretical results based on linearized hydrodynamics, we demonstrate that time-dependent hydrodynamic interactions lead to synchronization of the rotational motion. Thermal noise implies large fluctuations of the phase-angle difference between the rotors, but synchronization prevails and the ensemble-averaged time dependence of the phase-angle difference agrees well with analytical predictions. Moreover, we demonstrate that compressibility effects lead to longer synchronization times. In addition, the relevance of the inertia terms of the Navier-Stokes equation are discussed, specifically the linear unsteady acceleration term characterized by the oscillatory Reynolds number ReT. We illustrate the continuous breakdown of synchronization with the Reynolds number ReT, in analogy to the continuous breakdown of the scallop theorem with decreasing Reynolds number.
我们通过多粒子碰撞动力学（MPC）模拟研究了流体动力学耦合微转子的涌现动力学行为。两个转子被限制在一个平面内，并在主动力驱动下沿圆周运动。将模拟结果与基于线性化流体动力学的理论结果进行比较，我们证明了随时间变化的流体动力学相互作用会导致旋转运动的同步。热噪声意味着转子之间相角差的大幅波动，但同步仍然存在，并且相角差的系综平均时间依赖性与分析预测结果吻合良好。此外，我们证明了可压缩性效应会导致更长的同步时间。另外，还讨论了纳维-斯托克斯方程中惯性项的相关性，特别是以振荡雷诺数ReT为特征的线性非定常加速度项。我们说明了同步随着雷诺数ReT的连续破坏，这类似于随着雷诺数减小扇贝定理的连续破坏。
