Predicting Dynamic Response of Structural Cables and Power Transmission Lines in Hurricanes and Other Windstorms

在各种工程应用中，如悬索桥、悬索桥顶、桁架格塔和电力传输中，电缆经常以成组/束的形式使用。这些电缆在单独的风和风与降水（雨或冰）结合时容易产生大幅度的振动。振动会导致电缆疲劳损伤，在某些情况下会导致电缆灾难性失效，对安全构成威胁。过去的研究涉及光滑表面的单个电缆，提高了对涡激和风雨激振动现象的理解。然而，需要一种可靠的风荷载模型，用于预测在湍流和瞬态风中，在中高风速下捆扎电缆的动态响应。这项研究是为了提高缆索支撑结构和输电线路中使用的电缆在飓风和其他风暴危害下的弹性。这项研究将促进制定/评估可能的缓解战略，从而建立可靠的民用和电力基础设施。在本项目中，将采用协同计算和实验方法研究裸电缆和冰覆盖电缆的飞奔，以解决技术差距。具体目标是：(a)提高对中至高风速下电缆支撑结构和高压输电线路中使用的单根和捆扎电缆的气动弹性（运动诱导）行为的理解，(b)了解上游湍流、非均匀流、瞬态流和尾迹诱导流对电缆响应的影响，以及(c)开发一个鲁棒的时域气动弹性载荷公式来预测电缆的振动幅度。该研究包括使用大涡模拟的高保真计算流体动力学，以及使用单、多圆柱体截面模型和气动弹性模型的风洞实验。模拟和实验将针对裸电缆和覆盖冰的电缆进行单组和组组配置。计算模拟和风洞实验结果的比较将为这两种方法提供可信度。该项目的主要产品将是电缆的风荷载模型和一种方法，该方法可以用作结构分析的工具，以确定给定风场结构或电力线中的电缆的脆弱性。

Cables are often used in groups/bundles in a variety of engineering applications such as in suspension bridges, suspended roofs, guyed lattice towers, and power transmission. These cables are prone to large-amplitude vibrations in wind alone and in wind combined with precipitation (rain or ice). The vibrations can lead to fatigue damage and in some cases catastrophic failure of cables posing a threat to safety. Past investigations involving individual cables with smooth surface have resulted in an improved understanding of vortex-induced and rain-wind-induced vibration phenomena. However, there is a need for a credible wind load model that can be used to predict the dynamic response of bundled cables in turbulent and transient wind at moderate to high wind speeds. This research is to improve the resilience of cables used in cable-supported structures and power transmission lines to hazards of hurricanes and other windstorms. The study will facilitate development/evaluation of potential mitigation strategies leading to a reliable civil and power infrastructure. In this project, a synergistic computational and experimental approach will study galloping of bare-cable and cable covered with ice to address the technology gaps. The specific objectives are (a) to improve understanding of aeroelastic (motion-induced) behavior of a single and bundled cables used in cable-supported structures and high-voltage power transmission lines in moderate to high wind speeds, (b) to understand the effects of upstream turbulence, non-uniform flow, transient flow, and wake-induced flow on cable response, and (c) to develop a robust time-domain aeroelastic load formulation to predict cable vibration amplitude. The study involves high-fidelity computational fluid dynamics using large eddy simulation, and wind tunnel experiments using section models of single and multiple cylinders and aeroelastic models. The simulation and experiments will be for bare-cables and cables covered with ice in single and grouped configurations. Comparison of computational simulation and wind tunnel experiment results will provide credibility to both procedures. The primary product of this project will be a wind-load model for cables and a methodology that can be used as a tool in structural analysis to identify the vulnerability of cables in a structure or power line at a given wind site.