Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China.
Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China.
Phys Rev E. 2017 Dec;96(6-1):062138. doi: 10.1103/PhysRevE.96.062138. Epub 2017 Dec 26.
We model the two-dimensional dynamics of a pointlike artificial microswimmer diffusing in a harmonic trap subject to the shear flow of a highly viscous medium. The particle is driven simultaneously by the linear restoring force of the trap, the drag force exerted by the flow, and the torque due to the shear gradient. For a Couette flow, elliptical orbits in the noiseless regime, and the correlation functions between the particle's displacements parallel and orthogonal to the flow are computed analytically. The effects of thermal fluctuations (translational) and self-propulsion fluctuations (angular) are treated separately. Finally, we discuss how to extend our approach to the diffusion of a microswimmer in a Poiseuille flow. These results provide an accurate reference solution to investigate, both numerically and experimentally, hydrodynamics corrections to the diffusion of active matter in confined geometries.
我们对一个在受高度粘性介质剪切流影响的简谐势阱中扩散的点状人工微泳体的二维动力学进行建模。该粒子同时受到势阱的线性回复力、流体力的阻力和剪切梯度产生的扭矩的驱动。对于 Couette 流，在无噪声情况下，粒子的位移在平行和垂直于流的方向上呈现椭圆形轨道，并且计算出它们之间的相关函数。分别处理热涨落（平移）和自推进涨落（旋转）的影响。最后，我们讨论如何将我们的方法扩展到微泳体在泊肃叶流中的扩散。这些结果为研究受限几何形状中活性物质扩散的流体动力学修正提供了一个准确的参考解，无论是数值还是实验。
