Low flow drag is of great importance to a variety of engineering applications, and an effective way to achieve low drag is to use bioinspired microstructured surfaces. This work aims to reduce the skin-friction drag in closed channel flow using textured surfaces inspired by leaves of indocalamus and rice. A channel formed from a polydimethylsiloxane chunk and a silicon wafer was fabricated to study the drag reduction behavior for water or liquid paraffin oil in laminar flow. Bioinspired textures were processed on the silicon wafer surface using the deep silicon plasma etching method. The pressure drop of water or paraffin oil passing through textured channels with different velocities was measured. The maximum pressure drop reductions for the paraffin oil flow with a low velocity (Re ≈ 1) and for the water flow with a high velocity (Re < 1000) were about 5.1 and 27.3%, respectively. The contact angles of the bioinspired textured surface are also presented, and mechanisms to explain the drag reduction are proposed. Hydrophobicity leading to a change from a liquid–solid interface to a liquid–air interface is believed to provide the drag reduction for water flow, while the thin oil film formed on the textured surface due to oleophilicity helps reduce the oil flow drag.

中文翻译：

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使用仿生纹理表面减少封闭通道中的层流阻力

低流动阻力对于各种工程应用都非常重要，实现低阻力的有效方法是使用仿生微结构表面。这项工作的目的是利用受箬竹和水稻叶子启发的纹理表面来减少封闭通道流中的皮肤摩擦阻力。制造了由聚二甲基硅氧烷块和硅片形成的通道，以研究层流中水或液体石蜡油的减阻行为。使用深硅等离子体蚀刻方法在硅片表面加工出仿生纹理。测量了水或石蜡油以不同速度通过纹理通道的压降。低速石蜡油流 (Re ≈ 1) 和高速水流 (Re < 1000) 的最大压降降低分别约为 5.1% 和 27.3%。还介绍了仿生纹理表面的接触角，并提出了解释减阻的机制。疏水性导致液-固界面转变为液-气界面，被认为可以减少水流阻力，而由于亲油性而在纹理表面上形成的薄油膜有助于减少油流阻力。