论文标题
斯托克斯在具有奇特和奇异竞争粘度的三维流体中流动
Stokes flows in three-dimensional fluids with odd and parity-violating viscosities
论文作者
论文摘要
与粘性相比,当惯性力可忽略不计时,Stokes方程描述了流体的运动。在本文中,我们探讨了在三个维度上流动的均衡性侵略性和非差异(即奇数)粘度的结果。均衡性粘度是粘度张量的系数,在空间的镜像反射下并不不变,而奇数粘度是那些不影响机械能消散的粘度。这些粘度可能发生在从合成和生物活性流体到磁性和旋转流体的系统中。我们首先系统地列举了与圆柱形对称性兼容的所有可能平价侵略性粘度,从而突出了它们与潜在的微观实现的联系。然后,使用分析方法和数值方法的组合,我们分析了平均侵略性粘度对Stokeslet溶液的影响,对球或气泡经过的流以及许多颗粒沉积的影响。在我们分析的所有情况下,即使驱动力与圆柱形对称性的轴平行,平等侵略性粘度也会产生方位流。对于一些沉积颗粒,与传统的Stokes流相比,方位角流弯曲了轨迹。对于粒子云,方位角流阻碍球形云到圆环中,然后将随后的分解为较小的部分,否则会发生。圆柱对称系统(球体,气泡,颗粒云)中方位角流的存在可以用作实验系统中平等竞选粘度的探针。
The Stokes equation describes the motion of fluids when inertial forces are negligible compared to viscous forces. In this article, we explore the consequence of parity-violating and non-dissipative (i.e. odd) viscosities on Stokes flows in three dimensions. Parity-violating viscosities are coefficients of the viscosity tensor that are not invariant under mirror reflections of space, while odd viscosities are those which do not contribute to dissipation of mechanical energy. These viscosities can occur in systems ranging from synthetic and biological active fluids to magnetised and rotating fluids. We first systematically enumerate all possible parity-violating viscosities compatible with cylindrical symmetry, highlighting their connection to potential microscopic realizations. Then, using a combination of analytical and numerical methods, we analyze the effects of parity-violating viscosities on the Stokeslet solution, on the flow past a sphere or a bubble, and on many-particle sedimentation. In all the cases we analyze, parity-violating viscosities give rise to an azimuthal flow even when the driving force is parallel to the axis of cylindrical symmetry. For a few sedimenting particles, the azimuthal flow bends the trajectories compared to a traditional Stokes flow. For a cloud of particles, the azimuthal flow impedes the transformation of the spherical cloud into a torus and the subsequent breakup into smaller parts that would otherwise occur. The presence of azimuthal flows in cylindrically symmetric systems (sphere, bubble, cloud of particles) can serve as a probe for parity-violating viscosities in experimental systems.