论文标题
流体流动在活性列缺陷动力学中的作用
The role of fluid flow in the dynamics of active nematic defects
论文作者
论文摘要
我们适应Halperin-Mazenko形式主义，以分析与通用流体流相结合的二维活性nematics。控制流体动力方程导致了列神经拓扑缺陷及其相应密度场的进化定律。我们发现，$ \ pm 1/2 $缺陷是由局部流体流动的推动，并通过列表方向加上流量剪切速率。在过度阻尼且可压缩的极限中，我们恢复了+1/2缺陷的先前获得的主动自我prop。非本地流体动力学效应主要对于不可压缩的流动是显着的，因此不可能消除流体速度，而不是仅靠局部缺陷极化。对于两个相反电荷的缺陷的情况，非局部流体动力相互作用是由非转向性压力梯度力介导的。最后，我们得出了连续方程的缺陷气体与任意（可压缩或不可压缩的）流体流相关的缺陷气体。
We adapt the Halperin-Mazenko formalism to analyze two-dimensional active nematics coupled to a generic fluid flow. The governing hydrodynamic equations lead to evolution laws for nematic topological defects and their corresponding density fields. We find that $\pm 1/2$ defects are propelled by the local fluid flow and by the nematic orientation coupled with the flow shear rate. In the overdamped and compressible limit, we recover the previously obtained active self-propulsion of the +1/2 defects. Non-local hydrodynamic effects are primarily significant for incompressible flows, for which it is not possible to eliminate the fluid velocity in favor of the local defect polarization alone. For the case of two defects with opposite charge, the non-local hydrodynamic interaction is mediated by non-reciprocal pressure-gradient forces. Finally, we derive continuum equations for a defect gas coupled to an arbitrary (compressible or incompressible) fluid flow.
