Superhydrophobicity, drag reduction and microfluidic flow

在厚度在微米量级或更小的微器件中，微薄膜和液体的流动受到固液界面流体动力学特性的强烈影响。本研究的目的是阐明固体表面的疏水性(缺乏润湿性)与微流体流之间的联系，并阐明滑移减阻的机理。在实验的密切指导下，我们将从理论上检验三种不同的结构。鉴于一般边界层流动的重要性和与薄膜的密切联系，我们将首先深入探讨一般边界层流动。与粘性液体流动相反，滑移液体的BL流在性质上是不相似的，因此处理起来困难得多。接下来将研究射流撞击水平板和水跃的流动，因为已经对光滑和波纹平板进行了大量的实验工作。最后，对通道出口附近的微通道流动和微喷流进行了研究。

The flow of microfilms and liquids in microdevices, with thickness on the order of microns or smaller, is strongly influenced by the hydrodynamic characteristics at the solid-liquid interface. The aim of our research is to clarify the connection between the hydrophobicity (lack of wettability) of the solid surface and microfluidic flow, and elucidate the mechanism of drag reduction resulting from slip. Three different configurations will be examined theoretically, with close guidance from experiment. Given its fundamental importance and close connection to thin films, general boundary-layer (BL) flow will be explored first in some depth. Contrary to adhering liquid flow, the BL flow of slipping liquid is non-similar in character, and therefore much more difficult to treat. The flow of a jet impinging on a horizontal plate and hydraulic jump will be studied next, as extensive experimental work has been performed for smooth and corrugated plates. Finally, microchannel flow and micro-jet flow will be examined near the channel exit.