Study of Microburst Winds and Their Loading Effects on Built Structures

该项目的目的是进行一项基础研究，以量化猛烈微爆风的特征及其对地面土木结构的载荷影响。本研究采用了一种协同方法，包括使用翻译微冲击模拟器和土木结构的比例模型进行实验室模拟，使用CFD进行数值模拟，以及验证模拟流场的现场数据。粒子图像测速技术用于提供详细的流场测量，而现有的CFD模型被扩展到包括浮力效应，以验证由冷空气下降产生的自然微爆与实验室模拟产生的微爆之间的相似性。详细研究了微爆裂风作用下非定常流动结构的特性及其对土木结构产生的风荷载。这项研究的结果之一将是了解不同地形下微爆风的风速分布，以及典型土木结构的空气动力载荷目录，这将对未来此类结构的设计有用。该项目的目标是阐明潜在的物理特性，以便更好地了解微爆风危害，从而更准确地预测风力对建筑结构的潜在破坏，最终目标是减少人员伤亡和经济损失。整个社会将从改进的近地强风潜在破坏预测和改进的建筑或设计规范中受益匪浅，这些规范有助于减轻这类风的危害。该项目还将通过改进课程、实验室演示、基于互联网的传播和新闻媒体渠道，使研究生、本科生和K-12学生以及一般公众受益。

The objective of this project is to conduct a fundamental study to quantify the characteristics of violent microburst winds and their loading effects on ground-based civil structures. A synergistic approach is used in this study that involves laboratory simulations using a translating microburst simulator and scaled models of civil structures, numerical simulations using CFD, and field data for validation of the simulated flow field. Particle Image Velocimetry is used to provide detailed flow-field measurements while existing CFD models are extended to include buoyancy effects to verify the similarities between a natural microburst generated by descending cold air with those generated in laboratory simulations. The characteristics of unsteady flow structures of microburst winds and resultant wind loads on civil structures are investigated in great detail. One of the outcomes of this study will be knowledge of wind-speed profiles of microburst winds in various terrains, and a catalog of aerodynamic loads for typical civil structures that will be useful for future design of such structures. The goal of this project is to elucidate the underlying physics for a better understanding of microburst wind hazard in order to provide more accurate prediction of wind damage potential to built structures with the ultimate goal of reducing the loss of life or injury and economic loss. Society at large will benefit significantly from improved predictions of damage potential of violent near-ground winds and improved building or design codes that can help in mitigating this type of wind hazard. This project will also benefit graduate, undergraduate and K-12 students as well as public in general through improved curricula, laboratory demonstrations, Internet-based disseminations and news media outlets.