CAREER: Flow Physics of Transient Rooftop Vortices at High Reynolds Numbers and Bio-Inspired Flow Control Strategies to Mitigate Wind Hazards

职业：高雷诺数瞬态屋顶涡流的流动物理学和减轻风害的仿生流动控制策略

• 批准号: 1944776
• 负责人: Wei Zhang
• 金额: $ 58.02万
• 依托单位: Cleveland State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1944776&HistoricalAwards=false
• 关键词: CAREER; Flow; Physics; Transient; Rooftop

This Faculty Early Career Development (CAREER) grant will advance scientific knowledge of the flow physics of rooftop vortices from hurricane-type strong winds on low-rise buildings and develop bio-inspired flow control strategies to attenuate the damaging effects of roof suctions on building resilience. Dramatic damage repeatedly occurs on low-rise building roofs during windstorms, as observed in recent hurricanes Matthew (2016), Maria (2017), and Michael (2018). Building roof failure often starts at the windward roof edges and corners, where extreme peak suctions are induced by flow separation and unsteady vortices. Improved understanding of vortex dynamics governing the worst roof suction and smart flow control strategies by learning from nature will contribute towards more accurate wind load prediction, enhanced wind design provisions, and reduction of wind-induced damage and economic and life losses, and thus advance post-windstorm national welfare and prosperity. The bio-inspiration approach will not only produce cost-effective, high-performance mitigation strategies for low-rise buildings, but will also motivate new thinking in broader engineering fields. This research will use the Natural Hazards Engineering Research Infrastructure (NHERI) Wall of Wind (WOW) facility at Florida International University (FIU). Experimental datasets will be archived in the NHERI Data Depot (https://www.DesignSafe-ci.org) and be made publicly available for validation of computational fluid dynamics (CFD) models. To strengthen the persistence of engineering students, first-year undergraduate students will be engaged in a new learning community by integrating scientific questions into team-based, early research experiences, as well as weekly open workshops and invited seminars. The learning community program will improve the STEM infrastructure, broaden underrepresented groups’ participation in engineering, and build a pipeline for the engineering workforce. This project will support the investigator's long-term career vision focused on fundamental research on wind-structure interaction and bio-inspired flow control to increase the wind resilience of civil infrastructure that contributes to community resilience and sustainability. This award contributes to the National Science Foundation's role in the National Windstorm Impact Reduction Program (NWIRP). The specific research objectives are the following: (1) quantify three-dimensional, transient rooftop vortices from hurricane-type high winds of high Reynolds numbers, (2) correlate the unsteady vortices with roof peak pressures, and (3) utilize bio-inspiration as an innovation tool to create cost-effective wind mitigation devices, ultimately enhancing the wind resiliency of low-rise buildings. A series of well-controlled wind tunnel experiments with unsteady flow and pressure over a scaled low-rise building model will be conducted at Cleveland State University and the FIU WOW facility. Systematic measurements of the unsteady three-dimensional vortical flow at high Reynolds numbers will also be beneficial to the broader fluid mechanics community to advance understanding, modeling, and control of a wide class of vortex flow phenomena. The research will result in (1) vortex flow mechanisms governing the peak roof suctions at high Reynolds numbers, and (2) bio-inspired, cost-effective mitigation strategies (porous fractal parapets) to manipulate vortex formation, applicable to new and retrofit of existing low-rise buildings.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.

这项教师早期职业发展（Career）基金将推进低层建筑屋顶涡旋的流动物理科学知识，并开发仿生流动控制策略，以减弱屋顶吸力对建筑弹性的破坏性影响。在暴风雨期间，低层建筑屋顶会反复发生严重破坏，正如最近的飓风马修（2016）、玛丽亚（2017）和迈克尔（2018）所观察到的那样。建筑物屋顶的破坏通常始于迎风的屋顶边缘和角落，在那里，流动分离和非定常涡流会诱发极端峰值吸力。通过向大自然学习，提高对控制最恶劣屋顶吸力的涡旋动力学的理解和智能流量控制策略，将有助于更准确的风荷载预测，增强风设计规定，减少风引起的损害以及经济和生命损失，从而促进风暴后的国家福利和繁荣。这种以生物为灵感的方法不仅可以为低层建筑提供具有成本效益的高性能缓解策略，还可以在更广泛的工程领域激发新思维。这项研究将使用佛罗里达国际大学（FIU）的自然灾害工程研究基础设施（NHERI）风墙（WOW）设施。实验数据集将存档在NHERI数据仓库（https://www.DesignSafe-ci.org）中，并公开用于验证计算流体动力学（CFD）模型。为了加强工程专业学生的毅力，一年级本科生将参与一个新的学习社区，通过将科学问题整合到以团队为基础的早期研究经验中，以及每周的公开研讨会和邀请研讨会。学习社区计划将改善STEM基础设施，扩大未被充分代表的群体对工程的参与，并为工程劳动力建立管道。该项目将支持研究者的长期职业愿景，专注于风-结构相互作用和生物启发流控制的基础研究，以提高民用基础设施的抗风能力，从而有助于社区的恢复力和可持续性。该奖项有助于国家科学基金会在国家减少风暴影响计划（NWIRP）中的作用。具体研究目标如下：(1)量化高雷诺数飓风型大风产生的三维瞬态屋顶涡旋；(2)将非定常涡旋与屋顶峰值压力关联起来；(3)利用生物灵感作为创新工具，创造具有成本效益的降风装置，最终提高低层建筑的抗风能力。一系列控制良好的非定常流和压力风洞实验将在克利夫兰州立大学和FIU WOW设施进行。对高雷诺数下的非定常三维涡旋流的系统测量也将有利于更广泛的流体力学社区，以促进对各种涡旋流现象的理解、建模和控制。该研究将得出(1)高雷诺数下控制峰值屋顶吸力的涡流流动机制，以及(2)生物启发的、具有成本效益的缓解策略（多孔分形胸墙）来控制涡流的形成，适用于新建和改造现有的低层建筑。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

项目成果

Comparison and uncertainty quantification of roof pressure measurements using the NIST and TPU aerodynamic databases

• DOI: 10.1016/j.jweia.2022.105246
• 发表时间: 2023-01
• 期刊: Journal of Wind Engineering and Industrial Aerodynamics
• 影响因子: 4.8
• 作者: E. Shelley;Erin Hubbard;W. Zhang

Wind-Tunnel Experiments of Turbulent Wind Fields over a Two-dimensional (2D) Steep Hill: Effects of the Stable Boundary Layer

二维 (2D) 陡山上湍流风场的风洞实验：稳定边界层的影响

• DOI: 10.1007/s10546-023-00820-2
• 发表时间: 2023
• 期刊: Boundary-Layer Meteorology
• 影响因子: 4.3
• 作者: Zhang, Wei;Markfort, Corey D.;Porté-Agel, Fernando
• 通讯作者: Porté-Agel, Fernando

A Case Study of Wind Characteristics Affected by Terrain Features and Atmospheric Thermal Stability

受地形特征和大气热稳定性影响的风特性实例研究

• 发表时间: 2022
• 期刊: 14th Americas Conference on Wind Engineering
• 作者: Wei Zhang;Yuping Wu;Corey Markfort
• 通讯作者: Corey Markfort