At finite Reynolds numbers, particles migrate across flow streamlines to their equilibrium positions in microchannels. Such a migration is attributed to an inertial lift force, and it is well known that the equilibrium location of neutrally buoyant particles is determined only by their size and the Reynolds number. Here we demonstrate that the decoration of a bottom wall of the channel by superhydrophobic grooves provides additional possibilities for manipulation of neutrally buoyant particles. It is shown that the effective anisotropic hydrodynamic slip of such a bottom wall can be readily used to alter the equilibrium positions of particles and to generate their motion transverse to the pressure gradient. These results may guide the design of novel inertial microfluidic devices for efficient sorting of neutrally buoyant microparticles by their size.

中文翻译：

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中性浮力颗粒在超疏水通道中的惯性迁移

在有限的雷诺数下，颗粒跨流线迁移到微通道中的平衡位置。这种迁移归因于惯性升力，众所周知，中性浮力颗粒的平衡位置仅由它们的大小和雷诺数确定。在这里，我们证明了通过超疏水性沟槽对通道底壁的装饰为中性浮力颗粒的处理提供了其他可能性。结果表明，这种底壁的有效各向异性流体动力滑移可以很容易地用于改变颗粒的平衡位置并产生横向于压力梯度的运动。