Analytical Method to Assess Dynamic Response of Tall Buildings to Downburst Windstorm

高层建筑和水平轴风力发电机等竖向结构容易受到复杂的风-结构相互作用引起的风致振动和潜在的破坏。近年来，由于美国和世界其他地区倾向于建造更高的建筑物和更大直径的叶片风力涡轮机，这个问题的相关性吸引了工程研究人员。高层建筑结构的设计通常是基于稳定和平稳的风荷载条件。然而，风往往是短暂的，例如在下击暴流风暴的情况下，这是一种气象现象，它会在地面附近引起破坏性风荷载的爆发。瞬态风荷载的研究也是相关的，因为越来越多的结构被这种类型的事件损坏。本计画旨在发展一种可行的计算方法，以评估高层建筑物在下击暴流下的动态反应。本计画将寻求一种新的分析方法，以评估高层建筑物在瞬时风荷载作用下的随机动力反应。该方法将考虑系统非线性和气动耦合效应。该方法将基于紧支撑小波和小波-伽辽金变换的概念，通过保留建模中的时频特征，将微分方程系统简化为代数形式。本文的研究将进一步推动小波-伽辽金法在风振耦合非线性随机动力问题中的应用。此外，该项目将调查动态，所造成的瞬态下击暴流风，对一系列的高层建筑的降阶模型。例子将包括两个基准高层建筑和一个大直径水平轴风力涡轮机。研究将通过对基准建筑物的缩尺模型进行风洞实验来验证分析方法。计划开展综合外联活动，通过教育工具传播研究结果。

Vertical structures such as tall buildings and horizontal-axis wind turbines are prone to wind-induced vibrations and potential damage originating from complex wind-structure interaction. The relevance of this issue has attracted engineering researchers in recent years because of the tendency to erect taller buildings and larger-diameter-blade wind turbines in the United States and other parts of the World. The design of tall structures is usually based on steady and stationary wind load conditions. However, winds are often transient, such as in the case of a downburst storm, a meteorological phenomenon which induces an outburst of damaging wind loads near the ground. The study of transient wind loads is also relevant since increasing number of structures is damaged by this type of events. This project pursues to develop a viable computational method for the dynamic response assessment of tall structures against a downburst type of storm. This project will pursue a novel analytical method for assessing the stochastic dynamic response of tall structures due to transient wind loads. The method will account for system nonlinearity and aerodynamic coupling effects. The method will be based on the concepts of compactly supported wavelets and the Wavelet-Galerkin transform, which enables reducing a system of differential equations to an algebraic form by preserving time-frequency features in the modeling. The study will advance the utilization of Wavelet-Galerkin method for solving wind-induced coupled nonlinear stochastic dynamic problems. Moreover, the project will investigate the dynamics, caused by transient downburst-like winds, on a series of reduced-order models of tall structures. Examples will include two benchmark tall buildings and one large-diameter horizontal-axis wind turbine. The research will validate the analytical method by conducting wind tunnel experiments on scaled models of the benchmark buildings. Integrated outreach activities are planned to disseminate the findings of the study through educational tools.