SGER: A Biomimetic Surface Roughness Geometry for Boundary Layer Control

建议没有。机构：阿拉巴马大学- TUSCALOOSASGER：一种用于边界层控制的仿生表面粗糙度几何。该资助将支持探索性实验研究，以调查仿生粗糙度几何上的边界层流动。这种表面模仿了可以在快速游动的鲨鱼皮肤上观察到的粗糙的微观几何形状的形成，科学家们推测，当它们以更快的游动速度追逐猎物时，它们的牙齿（鳞片）会竖起来。假设这样的表面几何形状可能导致齿齿之间形成三维腔涡阵列，因此表面上复杂的部分滑移条件可能强烈影响边界层向湍流的过渡。根据流动的雷诺数（基于空腔的高度或小齿的大小）和边界层的厚度，结果可能是表面的皮肤摩擦减少或增强。这项研究的结果可能会让我们深入了解为什么快速的鲨鱼，比如短鳍鲭鲨（Isurus Oxyrinchus），据信可以达到60英里每小时以上的速度，比速度较慢的鲨鱼物种有更小的牙。另一个暗示是，由于在试图游过某一速度时阻力突然增加，具有较大齿状物的鲨鱼可能无法达到更高的速度。该项目的智力价值在于对一种方法的潜在理解和应用，通过这种方法，大自然已经找到了减少固体表面表面摩擦的解决方案，从而控制边界层流动并将其转变为湍流。这种控制边界层的新方法不仅会被发现，从而导致节约能源的新技术创新，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广泛影响包括：减少阻力（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，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，这样的发现也可以很好地纳入鼓励追求科学和工程事业的K-12扩展计划。

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.