Directional locking and deterministic separation in periodic arrays
Directional locking and deterministic separation in periodic arrays
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DOI：
10.1017/s0022112009005941
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发表时间：
2009-05-25
影响因子：
3.7
通讯作者：
Drazer, German
中科院分区：
文献类型：
--
作者：
Frechette, Joelle;Drazer, German
我们研究了非布朗球悬浮在静止流体中的动力学，并通过一个恒定的外力作用下的固体障碍物的周期性阵列移动的斯托克斯动力学模拟。我们表明，在存在或非流体动力学，短程之间的相互作用的固体障碍物和悬浮球，移动的粒子成为锁定到周期性的轨迹与平均取向一致的晶格方向之一，是，在一般情况下，从驱动力的方向不同。锁定角取决于非流体动力学相互作用的细节，并可能导致不同物种的矢量分离的某些方向的外力。我们明确地表明存在分离的悬浮颗粒的混合物具有不同的粗糙度，移动通过一个正方形晶格的球形障碍物。我们还提出了一个稀释模型的基础上的两个粒子的迁移率和阻力函数的碰撞不同大小的球体。这个简单的模型预测了不同尺寸的颗粒的分离，并且还表明，使不同颗粒与固体障碍物之间的相互作用面积的差异最大化的微器件对于基于非流体动力学相互作用的尺寸分离将更敏感。
We investigate the dynamics of a non-Brownian sphere suspended in a quiescent fluid and moving through a periodic array of solid obstacles under the action of a constant external force by means of Stokesian dynamics simulations. We show that in the presence or non-hydrodynamic, short-range interactions between the solid obstacles and the suspended sphere, the moving particle becomes locked into periodic trajectories with an average orientation that coincides with one of the lattice directions and is, in general, different from the direction of the driving force. The locking angle depends on the details of the non-hydrodynamic interactions and could lead to vector separation of different species for certain orientations of the external force. We explicitly show the presence of separation for a Mixture of Suspended particles with different roughness, moving through a square lattice of spherical obstacles. We also present a dilute model based on the two-particle mobility and resistance functions for the collision between spheres of different sizes. This simple model predicts the separation of particles of different size and also suggests that microdevices that maximize the differences in interaction area between the different particles and the solid obstacles Would be more sensitive for size separation based on non-hydrodynamic interactions.