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EAGER: Novel Instrumentation for Extracting and Modeling of Flow Structure in Turbulent Boundary Layers

EAGER：用于湍流边界层中流动结构的提取和建模的新型仪器

基本信息

批准号：
1744146
负责人：
Mark Sheplak
金额：
$ 13万
依托单位：
University of Florida
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2018-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1744146&HistoricalAwards=false
关键词：
EAGER Novel Instrumentation Extracting Modeling

项目摘要

Development of new, more efficient aerodynamic vehicles is a constantly ongoing process. There are many areas of improvement that can be targeted, including reduced drag, enhanced maneuverability, and reduced noise levels. Although there is a long track record of research in aerodynamics, many of the basic properties of fluid flows are not completely understood. For instance, how forces along the surface of a body in motion relate to velocity in the surrounding air. Part of the reason is a lack of proper tools for measuring these flow interactions, which limits the experiments that can be performed. This project looks to develop new tools for the measurement of the flow-generated friction in multiple directions such that they can be combined with existing tools that estimate flow velocity with an ultimate goal of generating comprehensive experimental models of the turbulent motions. Information revealed from these efforts will enhance understanding of fundamental turbulent flows, which can be generalized to other more complex interactions. Furthermore, broad advances in sensor technology can be used by other research groups in their future endeavors, enabling increases in the next generation of aerodynamic performance.A full understanding of the interplay between wall forces and freestream fluid velocity within turbulent flow fields remains elusive and its study requires new technologies. Specifically, the temporal relationship between fluctuating wall shear stress and large scale motion of coherent turbulent structures in a boundary layer, among others. A key limitation to experimental validation of various models is insufficient measurement instrumentation, especially in multi-dimensional flows. Microelectromechanical system (MEMS) based transducers are developed to address this gap, including extending wall shear stress measurement capabilities from single-axis to time-resolved vectors. Specifically, a dual-axis, differential capacitive floating element skin friction sensor possessing a hydraulically smooth package is proposed. The novel sensor will provide the opportunity to sample the velocity field triggered by high-shear events allowing for greater insight into numerous open questions on turbulent boundary layers, including eddy formation, propagation, and the accuracy of the horseshoe vortex model. It will also provide the ability to make time-resolved vector measurements of wall shear stress at the microscale, which does not currently exist. Development of the novel MEMS sensors will continue to expand on the growing suite of transducers tailored for fluid applications, leading to instrument grade tools for aerodynamicists to utilize elsewhere.

开发新的、更有效的空气动力学车辆是一个不断进行的过程。有许多方面的改进可以有针对性的，包括减少阻力，增强机动性，降低噪音水平。虽然空气动力学的研究有很长的历史，但流体流动的许多基本性质还没有完全了解。例如，沿着运动物体表面的力如何与周围空气的速度相关。部分原因是缺乏适当的工具来测量这些流动相互作用，这限制了可以进行的实验。该项目旨在开发用于测量多个方向上流动产生的摩擦的新工具，以便它们可以与估计流速的现有工具相结合，最终目标是生成湍流运动的综合实验模型。从这些工作中揭示的信息将增强对基本湍流的理解，这可以推广到其他更复杂的相互作用。此外，传感器技术的广泛进步可以被其他研究小组在未来的努力中所利用，从而提高下一代的气动性能。湍流场中壁面力和自由流动速度之间的相互作用仍然难以理解，其研究需要新的技术。具体地说，波动壁面剪应力和边界层中相干湍流结构的大尺度运动之间的时间关系，等等。各种模型的实验验证的一个关键限制是测量仪器不足，特别是在多维流中。基于微机电系统（MEMS）的传感器被开发以解决这一差距，包括将壁剪切应力测量能力从单轴扩展到时间分辨矢量。具体而言，双轴，差分电容浮动元件皮肤摩擦传感器具有液压光滑的封装提出。新型传感器将提供机会，采样由高剪切事件触发的速度场，从而更深入地了解湍流边界层上的许多悬而未决的问题，包括涡流的形成，传播和马蹄涡模型的准确性。它还将提供在微观尺度上对壁面剪切应力进行时间分辨矢量测量的能力，这是目前尚不存在的。新型MEMS传感器的开发将继续扩大为流体应用量身定制的传感器套件，从而为空气动力学家在其他地方提供仪器级工具。