CAREER: Characterization of Turbulence in Urban Environments for Wind Hazard Mitigation

在过去的十年里，极端风力事件造成的损失超过了所有其他自然灾害的损失总和。在飓风、龙卷风、雷暴暴发等现象中，美国几乎每个地区都面临着极端大风的风险。气候模型的预测预计这些灾害的发生和严重程度会升级，这突显出需要具有成本效益的设计概念来建造防风建筑。低层建筑和民用基础设施的结构完整性和长期性能受到地面附近大气湍流的严重影响，这些基础设施所在的地方。然而，缺乏对这种流动现象的坚实把握，限制了创建风险一致的设计指导的能力。这一学院早期职业发展(CALEAR)奖将支持试图通过促进对人口稠密环境中的湍流和结构上相关风荷载的基本理解来解决这一知识差距的研究。该项目将结合风洞实验、计算机模拟和流体力学的理论发展。该项目的成果将有助于提高抗风设计标准，促进国家福利和繁荣。研究活动将得到一个教育和推广计划的补充，该计划利用虚拟和增强现实技术的最新进展来改善教学和工程教育的可及性。该奖项将有助于美国国家科学基金会(NSF)在国家减少风灾影响计划(NWIRP)中扮演的角色。该项目的具体目标有两个：第一个是在静止和非稳定流动条件下表征城市地区极端风事件的湍流和基本机制；第二个是获得与精确表征风荷载条件相关的改进的流动统计分析公式。一系列广泛的风洞测试和对理想化城市环境中流动的高保真计算流体力学模拟将构成分析的基础。假设雷诺应力平衡方程的分析与现代模型简化和相干结构识别技术相结合，将使一阶和更高阶流动统计量对表面形态和流动强迫条件的依赖性的概念性公式得以发展。分析模型将被整合到建筑设计规范中，以提高低层结构的弹性，并对大规模社区对不断变化的风灾景观的弹性产生潜在的长期影响。该项目将利用美国国家科学基金会支持的佛罗里达大学自然危害工程研究基础设施(NHERI)边界层风洞，并将项目数据存档并公开提供给国家科学基金会数据仓库(https://www.DesignSafe-CI.org).This奖项反映了美国国家科学基金会的法定使命，通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In the past decade, losses from extreme wind events have exceeded those from all other natural disasters combined. Among hurricanes, tornadoes, thunderstorm downbursts, and other phenomena, virtually every region of the U.S. is at risk of extreme winds. Predictions from climate models anticipate an escalation in the occurrence and severity of these hazards, underscoring the need for cost-effective design concepts to create wind-resistant buildings. The structural integrity and long-term performance of low-rise buildings and civil infrastructure are heavily influenced by atmospheric turbulence near ground level where this infrastructure exists. Yet, a solid grasp of this flow phenomenon is lacking, limiting the ability to create risk-consistent design guidance. This Faculty Early Career Development (CAREER) award will support research that attempts to address this knowledge gap by advancing the fundamental understanding of turbulence in densely populated environments and the associated wind loads on structures. The project will utilize a combination of wind tunnel experiments, computer simulations, and theoretical developments in fluid dynamics. Findings from this project will enable improvements in wind-resistant design standards, bolstering national welfare and prosperity. Research activities will be complemented by an educational and outreach program leveraging recent advances in virtual and augmented reality technology to enhance teaching and accessibility to engineering education. This award will contribute to the U.S. National Science Foundation (NSF) role in the National Windstorm Impact Reduction Program (NWIRP).The specific objective of this project is twofold: the first is to characterize turbulence and fundamental mechanisms responsible for extreme wind events in urban areas under stationary and non-stationary flow conditions; the second is to derive improved analytical formulations for flow statistics that are relevant to the precise characterization of wind-loading conditions. An extensive series of wind tunnel tests and high-fidelity computational fluid dynamics simulations of flow over idealized urban environments will form the basis for the analysis. The hypothesis is that analysis of Reynolds stress budget equations combined with modern model reduction and coherent-structures identification techniques will enable the development of conceptual formulations encoding the dependency of first and higher order flow statistics onto surface morphology and flow forcing conditions. The analytical models will be derived for integration within building design codes to improve the resilience of low-rise structures, with potential long-lasting impacts on large-scale community resilience to the changing landscape of wind hazards. The project will utilize the NSF-supported Natural Hazards Engineering Research infrastructure (NHERI) Boundary Layer Wind Tunnel at the University of Florida and will archive and make publicly available the project data in the NHERI Data Depot (https://www.DesignSafe-CI.org).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.