Theory and Experiments for Distributed Roughness Effects in Laminar Boundary Layers

层流边界层中分布粗糙度效应的理论与实验

• 批准号: 1805889
• 负责人: Edward White
• 金额: $ 30万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-15 至 2022-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1805889&HistoricalAwards=false
• 关键词: Theory; Experiments; Distributed; Roughness; Effects

Identifying and modeling how distributed surface roughness affects laminar boundary layers is an important challenge in fundamental fluid mechanics. Its technological relevance relates to the role surface roughness plays in predicting aircraft skin friction, wind-turbine power production, and the performance of similar aerodynamic systems. Although aerodynamic roughness has been studied for nearly a century, a good understanding of its role has not yet been achieved. One reason may be that most studies have started from isolated roughness elements and attempted to build understanding from single elements to multiple elements. This research will pursue an alternative approach that addresses an entire field of distributed roughness using an analysis technique known as triple-deck asymptotics. The analytical results will be compared to wind-tunnel measurements of roughness fields to be manufactured using 3D printing. Additionally, the project will provide unique educational experiences for South Texas high-school students with STEM interests. These experiences will focus on the critical skills of dimensional analysis and scaling, key engineering concepts that underly the usefulness of both wind-tunnel testing, and triple-deck asymptotic analysis.To develop a whole-field approach, this project will pursue three research objectives. First, a theoretical model based on triple-deck asymptotic analysis will be implemented. This model will accommodate distributed roughness in both linear and nonlinear amplitude ranges. This technique is not widely used in an era of easy access to supercomputer-class numerical solutions. However, asymptotic analysis is ideally suited to studying distributed roughness because parameter studies are needed to characterize many roughness fields. Second, wind-tunnel measurements will be made over manufactured roughness specimens designed to validate key aspects of the theoretical predictions. Third, the validated model will be used to perform a parameter study that explores a wide range of roughness configurations and advances a new understanding of distributed roughness. Combining asymptotic analysis with validation experiments and then using the validated tool to perform wide-ranging parameter studies will significantly advance understanding of the roughness problem.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

识别和模拟分布的表面粗糙度如何影响层流边界层是基础流体力学中的一个重要挑战。其技术相关性涉及表面粗糙度在预测飞机表面摩擦、风力涡轮机发电和类似空气动力系统性能方面所起的作用。尽管人们对空气动力学粗糙度的研究已经进行了将近世纪，但对它的作用还没有很好的理解。一个原因可能是大多数研究都是从孤立的粗糙度元素开始的，并试图建立从单个元素到多个元素的理解。这项研究将寻求一种替代方法，解决了整个领域的分布粗糙度使用三层渐近分析技术。分析结果将与使用3D打印制造的粗糙度场的风洞测量结果进行比较。此外，该项目将为南德克萨斯州有STEM兴趣的高中生提供独特的教育体验。这些经验将集中在尺寸分析和缩放的关键技能，关键的工程概念，这两个风洞试验和三层渐近分析的有用性的基础。为了发展全场的方法，这个项目将追求三个研究目标。首先，将实施基于三层渐近分析的理论模型。该模型将适应线性和非线性幅度范围内的分布粗糙度。在一个容易获得超级计算机级数值解的时代，这种技术并没有被广泛使用。然而，渐近分析是非常适合研究分布粗糙度，因为参数的研究需要表征许多粗糙度领域。第二，风洞测量将在制造的粗糙度标本设计，以验证理论预测的关键方面。第三，验证模型将被用来进行参数研究，探讨了广泛的粗糙度配置和先进的分布粗糙度的新的理解。将渐近分析与验证实验相结合，然后使用验证工具进行广泛的参数研究，将大大提高对粗糙度问题的理解。该奖项反映了NSF的法定使命，并被认为是值得支持的，通过使用基金会的知识价值和更广泛的影响审查标准进行评估。

项目成果

Numerical Simulations of Asymptotic Theory for Distributed Roughness

分布粗糙度渐近理论的数值模拟

• DOI: 10.2514/6.2019-3536
• 发表时间: 2019
• 期刊: AIAA Aviation 2019 Forum
• 作者: McMillan, Madeline;White, Edward B.
• 通讯作者: White, Edward B.