Abstract.

Staggered and linear multi-particle trains constitute characteristic structures in inertial microfluidics. Using lattice-Boltzmann simulations, we investigate their properties and stability, when flowing through microfluidic channels. We confirm the stability of cross-streamline pairs by showing how they contract or expand to their equilibrium axial distance. In contrast, same-streamline pairs quickly expand to a characteristic separation but even at long times slowly drift apart. We reproduce the distribution of particle distances with its characteristic peak as measured in experiments. Staggered multi-particle trains initialized with an axial particle spacing larger than the equilibrium distance contract non-uniformly due to collective drag reduction. Linear particle trains, similar to pairs, rapidly expand toward a value about twice the equilibrium distance of staggered trains and then very slowly drift apart non-uniformly. Again, we reproduce the statistics of particle distances and the characteristic peak observed in experiments. Finally, we thoroughly analyze the damped displacement pulse traveling as a microfluidic phonon through a staggered train and show how a defect strongly damps its propagation.

Graphical abstract

中文翻译：

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惯性微流控中的粒子对和训练。

摘要。

交错的线性多粒子列构成惯性微流体中的特征结构。使用晶格玻尔兹曼模拟，我们研究了它们在流经微流体通道时的特性和稳定性。我们通过显示跨流线对如何收缩或扩展到其平衡轴向距离来确认其稳定性。相反，相同的流线对迅速扩展到一个特征分离，但即使很长一段时间也缓慢地分开。我们重现了在实验中测得的具有特征峰的粒子距离分布。由于集体阻力的减少，以大于平衡距离的轴向粒子间距初始化的交错多粒子列会不均匀收缩。线性粒子列，类似于线对，迅速扩展到大约是交错列车平衡距离两倍的值，然后非常缓慢地不均匀地分开。同样，我们重现了在实验中观察到的粒子距离和特征峰的统计数据。最后，我们彻底分析了阻尼位移脉冲以微流体声子的形式通过交错的列，并显示出缺陷如何强烈抑制其传播。

图形概要