Department of Mechanical Engineering, Clemson University, Clemson, South Carolina 29634, USA.
Department of Mechanical Engineering, Mahindra École Centrale, Hyderabad, Telangana 500043, India.
Phys Rev E. 2019 Dec;100(6-1):062207. doi: 10.1103/PhysRevE.100.062207.
In this work we study chaotic mixing induced by point microrotors in a bounded two-dimensional Stokes flow. The dynamics of the pair of rotors, modeled as rotlets, are non-Hamiltonian in the bounded domain and produce chaotic advection of fluid tracers in subsets of the domain. A complete parametric investigation of the fluid mixing as a function of the initial locations of the rotlets is performed based on pseudophase portraits. The mixing of fluid tracers as a function of relative positions of microrotors is studied using finite-time entropy and locational entropy. The finite-time locational entropy is used to identify regions of the fluid that produce good versus poor mixing, and this is visualized by the stretching and folding of blobs of tracer particles. Unlike the case of the classic blinking vortex dynamics, the velocity field of the flow modeled using rotlets inside a circular boundary is smooth in time and satisfies the no-slip boundary condition. This makes the considered model a more realistic case for studies of mixing in microfluidic devices using magnetic-actuated microspheres.
在这项工作中，我们研究了点微转子在有界二维 Stokes 流中引起的混沌混合。在有界区域中，双转子的动力学是非哈密顿的，会导致流体质点在域的子集中产生混沌输运。基于伪相位图，对作为转子初始位置函数的流体混合进行了全面的参数研究。使用有限时间熵和位置熵研究了微转子相对位置对流体混合的影响。有限时间位置熵用于识别产生良好和较差混合的流体区域，并通过追踪粒子团块的拉伸和折叠来可视化这一点。与经典的闪烁涡动力学不同，使用微转子在圆形边界内建模的流的速度场在时间上是平滑的，并且满足无滑移边界条件。这使得所考虑的模型成为使用磁驱动微球研究微流控设备中混合的更现实的情况。
