论文标题
有效微藻的强限制导致涡流流和增强混合的反转
Strong confinement of active microalgae leads to inversion of vortex flow and enhanced mixing
论文作者
论文摘要
微生物通过粘性液在其产生的流场中烙印其推进机制。这些游泳者之间在刚性边界之间的极端限制通常是在自然和技术环境中出现的，但是在这种制度中，其力学的测量不存在。在这里，我们表明，在两个平行板之间强烈限制了微alga衣原体，不仅通过与壁的接触摩擦来抑制其运动性，而且出于纯粹的机械原因，导致了周围涡流流的反转。实验的见解导致基于准2D Brinkman近似对Stokes方程的简化理论描述，而不是通常的图像方法。我们认为，尽管摩擦较高，但这种涡流流反转提供了增强的流体混合的优势。总体而言，我们的结果提供了一个综合框架，用于分析强烈的游泳者的集体流动。
Microorganisms swimming through viscous fluids imprint their propulsion mechanisms in the flow fields they generate. Extreme confinement of these swimmers between rigid boundaries often arises in natural and technological contexts, yet measurements of their mechanics in this regime are absent. Here, we show that strongly confining the microalga Chlamydomonas between two parallel plates not only inhibits its motility through contact friction with the walls but also leads, for purely mechanical reasons, to inversion of the surrounding vortex flows. Insights from the experiment lead to a simplified theoretical description of flow fields based on a quasi-2D Brinkman approximation to the Stokes equation rather than the usual method of images. We argue that this vortex flow inversion provides the advantage of enhanced fluid mixing despite higher friction. Overall, our results offer a comprehensive framework for analyzing the collective flows of strongly confined swimmers.
