论文标题
轴对称的stokes流动由于点力奇异性在两个同轴位置的刚性无滑动磁盘之间作用
Axisymmetric Stokes flow due to a point-force singularity acting between two coaxially positioned rigid no-slip disks
论文作者
论文摘要
我们根据稳定的Stokes方程进行理论上研究,该方程的粘性不可压缩流体由位于两个同轴定位的刚性圆盘的中心轴上的stokeslet引起的流动。 Stokeslet沿着中心轴定向。假定没有滑移边界条件在磁盘的表面上保持。我们在分析中对相关绿色的功能进行了计算,从而将流场的空间评估降低到可容纳数值处理的一维整合。为此,我们为围绕两个磁盘的粘性流量的流体动力问题提出了解决方案,作为混合接壤值问题,然后我们将其减少为四个双积分方程的系统。我们显示了在由两个磁盘界定的流体结构域中产生的粘性环形涡流的存在,这些磁盘通过相邻的反向涡流中包含中心轴的平面表现出来。此外,我们通过评估与轴向运动相关的流体动力迁移率函数来探测限制磁盘对点样粒子缓慢动力学的影响。因此,我们评估了常见的叠加近似值的适当性,并讨论了其有效性和适用性,这是系统的几何特性的函数。此外,我们通过有限元计算机模拟来补充我们的半分析方法,这揭示了一个很好的协议。我们的结果可能会发现在指导基于微粒的传感设备和小型电容器中电动传输的设计时。
We investigate theoretically on the basis of the steady Stokes equations for a viscous incompressible fluid the flow induced by a Stokeslet located on the centre axis of two coaxially positioned rigid disks. The Stokeslet is directed along the centre axis. No-slip boundary conditions are assumed to hold at the surfaces of the disks. We perform the calculation of the associated Green's function in large parts analytically, reducing the spatial evaluation of the flow field to one-dimensional integrations amenable to numerical treatment. To this end, we formulate the solution of the hydrodynamic problem for the viscous flow surrounding the two disks as a mixed-boundary-value problem, which we then reduce into a system of four dual integral equations. We show the existence of viscous toroidal eddies arising in the fluid domain bounded by the two disks, manifested in the plane containing the centre axis through adjacent counterrotating eddies. Additionally, we probe the effect of the confining disks on the slow dynamics of a point-like particle by evaluating the hydrodynamic mobility function associated with axial motion. Thereupon, we assess the appropriateness of the commonly-employed superposition approximation and discuss its validity and applicability as a function of the geometrical properties of the system. Additionally, we complement our semi-analytical approach by finite-element computer simulations, which reveals a good agreement. Our results may find applications in guiding the design of microparticle-based sensing devices and electrokinetic transport in small scale capacitors.