SGER: A Biomimetic Surface Roughness Geometry for Boundary Layer Control

提案编号： CTS-0630489主要制造商：AMY W. Langinstitution： 阿拉巴马大学-塔斯卡卢萨格：一个仿生表面粗糙度几何边界层控制这笔赠款将支持探索性的实验研究，调查边界层流动的仿生粗糙几何。 表面模仿粗糙的微观几何形状的形成，可以在快速游泳的鲨鱼皮肤上观察到，科学家们发现，当以更快的游泳速度追逐猎物时，它们有能力竖起它们的鳞片。 据推测，这样的表面几何形状可能会导致形成的三维阵列的空腔涡流之间形成的dennial，因此，一个复杂的部分滑移条件的表面可能会导致强烈影响过渡到湍流的边界层。 取决于流动的雷诺数（基于空腔高度或齿状物的尺寸）和边界层的厚度，结果可能是表面摩擦减小或增强。这项研究的结果可能会让我们深入了解为什么快速鲨鱼，如短鳍尖吻鲭鲨（Isurus Oxyrinchus）被认为可以达到每小时60英里以上的速度，比较慢的鲨鱼物种具有更小的密度。另一个含义是，具有较大密度的鲨鱼可能无法达到更高的速度，因为当试图游泳超过一定速度时，阻力会突然增加。 该项目的智力价值在于对一种手段的潜在理解和应用，通过这种手段，自然界已经找到了一种解决方案，用于减少固体表面上的表面摩擦，从而控制边界层流动及其向湍流的过渡。这种控制边界层的新方法不仅会被发现，导致新的技术创新，从而节约能源，而且对更好地了解鲨鱼的生物学和进化发展也会产生重大影响。 这种流动控制方法的更广泛的影响包括：减阻（例如，减少燃料需求和/或增加飞机、船舶、潜艇等的航程），分离控制，以及混合和传热增强（例如，计算硬件组件的冷却）。其他成果将包括培训本科生和研究生，目的是鼓励代表性不足的群体参与。 最后，这样的发现也很适合纳入K-12推广计划，鼓励追求科学和工程事业。

PROPOSAL NO.: CTS-0630489PRINCIPAL INVESTIGATORS: AMY W. LANGINSTITUTION: UNIVERSITY OF ALABAMA- TUSCALOOSASGER: A Biomimetic Surface Roughness Geometry for Boundary Layer ControlThis grant will support exploratory, experimental research to investigate the boundary layer flow over a biomimetic roughness geometry. The surface mimics the formation of a roughness micro geometry that can be observed on the skin of fast swimming sharks, conjectured by scientists to have the capability of bristling their denticles (scales) when in pursuit of prey at increased swimming speeds. It is hypothesized that such a surface geometry may lead to the formation of a three-dimensional array of cavity vortices forming between the denticles, and thus a complex partial slip condition over the surface may result strongly affecting the transition to turbulence in the boundary layer. Depending on the Reynolds number of the flow (based on the cavity height or size of the denticle) and the thickness of the boundary layer, the result could be either skin friction reduction or enhancement at the surface. Results from this study may give insight as to why fast sharks, such as the Shortfin Mako (Isurus Oxyrinchus) believed to achieve speeds upwards of 60 mph, have smaller denticles than slower shark species. Another implication is that sharks with larger denticles may not be able to achieve higher speeds due to a sudden increase in drag when attempting to swim past a certain speed. The intellectual merit of the project lies in the potential understanding and application of a means by which nature has already worked out a solution for the reduction of skin friction over a solid surface, resulting in the control of boundary layer flows and their transition to turbulence. Not only would this new method of boundary layer control be discovered, leading to new technological innovations resulting in energy conservation, but also the implications regarding a greater understanding of the biology and evolutionary development of sharks would be significant. The broader impacts of this method of flow control include: drag reduction (e.g. reduction in fuel requirements and/or increased range for aircraft, ships, submarines, etc.), separation control, and mixing and heat transfer enhancement (e.g. cooling of compute hardware components). Other outcomes will include the training of undergraduate and graduate students, with the goal of encouraging the participation of underrepresented groups. Finally, such a discovery would also lend itself well to incorporation into K-12 outreach programs that encourage the pursuit of careers in science and engineering.