SGER: A Biomimetic Surface Roughness Geometry for Boundary Layer Control

提案编号：CTS-0630489PRINCIPAL调查人员：艾米·W·朗格：阿拉巴马大学TUSCALOOSASGER：一种用于边界层控制的仿生表面粗糙几何这笔赠款将支持探索性的实验研究，以调查在仿生粗糙几何图形上的边界层流动。这个表面模仿了在快速游泳的鲨鱼的皮肤上可以观察到的粗糙微几何图形的形成，科学家推测，当以更快的游泳速度追逐猎物时，鲨鱼的牙齿(鳞片)具有竖起刷毛的能力。假设这样的表面几何形状可能会导致在齿轮间形成三维的空腔涡旋阵列，因此表面上复杂的部分滑移条件可能会强烈地影响边界层向湍流的转变。根据流动的雷诺数(基于牙洞的高度或大小)和边界层的厚度，结果可能是减少表面的表面摩擦，也可能是增加表面的摩擦。这项研究的结果可能会让我们深入了解为什么速度较快的鲨鱼，如短鳍Mako(Isurus Oxyrinchus)，据信速度可达每小时60英里以上，其牙齿比速度较慢的鲨鱼更小。另一个暗示是，当鲨鱼试图游过一定的速度时，由于阻力突然增加，牙齿较大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，大自然已经制定出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，导致新的技术创新，从而节省能源，而且对更好地理解鲨鱼的生物学和进化发展也将具有重要意义。这种流量控制方法的更广泛影响包括：减阻(例如减少飞机、船舶、潜艇等的燃料需求和/或增加航程)、分离控制以及增强混合和传热(例如计算机硬件组件的冷却)。其他成果将包括对本科生和研究生进行培训，目的是鼓励代表人数不足的群体参与。最后，这样的发现也将很好地被纳入鼓励在科学和工程领域追求职业的K-12外联计划。

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.