Study of Microburst Winds and Their Loading Effects on Built Structures

本项目的目标是进行一项基础研究，以量化剧烈微下击暴流风的特性及其对地基土木结构的荷载效应。在这项研究中使用的协同方法，涉及实验室模拟使用的翻译微下击暴流模拟器和缩放模型的土木结构，数值模拟使用CFD，和现场数据验证的模拟流场。粒子图像测速技术用于提供详细的流场测量，而现有的CFD模型扩展到包括浮力效应，以验证下降的冷空气产生的自然微下击暴流与实验室模拟产生的相似性。详细研究了微下击暴流的非定常流场结构特征及其对土木结构的风荷载。这项研究的成果之一将是在各种地形的微下击暴流风的风速剖面的知识，和典型的土木结构，这将是有用的，未来的设计，这样的结构的空气动力学载荷的目录。该项目的目标是阐明微下击暴流风灾害的基本物理机制，以便更准确地预测风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。改善对剧烈近地面风的破坏潜力的预测，以及改善有助于减轻这种风害的建筑或设计规范，将使整个社会受益匪浅。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.