Superhydrophobicity, drag reduction and microfluidic flow

厚度在微米级或更小的微器件中，微膜和液体的流动受到固液界面流体动力特性的强烈影响。我们的研究目的是阐明固体表面的疏水性（缺乏润湿性）与微流体流动之间的联系，并阐明滑移引起的减阻机理。在实验的密切指导下，将从理论上检验三种不同的构型。考虑到边界层流动的基本重要性及其与薄膜的密切联系，本文将首先深入探讨一般边界层流动。与黏着流体流动相反，滑动流体的BL流动在性质上不同，因此更难以处理。由于对光滑板和波纹板进行了大量的实验工作，接下来将研究射流撞击水平板和水力跳跃的流动。最后，将在通道出口附近检测微通道流动和微射流。

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.