Wind Gusts and their Dynamic Effects on Flexible Structures: Modeling and High-Resolution Simulations

本项目的目标是开发一种方法来有效地模拟和分析强湍流阵风对柔性轻质结构的影响。对于这些建筑的设计和尺寸确定来说，相当罕见但非常强烈的阵风与结构之间的高度动态相互作用是决定生存和稳定性的关键因素。与这些极端载荷相比，由标准大气湍流边界层描述的流动与尺寸、鲁棒性和耐久性几乎无关。对于后一种情况，在过去的几年里，已经做出了巨大的努力来开发耦合流体-结构相互作用（FSI）模拟工具，以研究柔性结构与湍流的相互作用。然而，到目前为止，文献中仅在很小程度上考虑了单个或多个阵风击中柔性结构导致极端载荷的载荷情况。该提案旨在通过开发一种模拟策略来缩小这一差距，该策略允许以有效的方式处理这种耦合和高度动态的物理过程。所考虑的长度和时间尺度被限制到本地windevents发生在microscale.Thus的主要目标和由此产生的好处是：-一种方法的发展，产生个别阵风或一系列这样的事件，通过在计算域内的注入和接近感兴趣的对象。基于源项公式的方法设计应特别考虑结构的反馈效应和由此产生的湍流对阵风本身的影响。它对于高湍流及其通过大涡模拟（LES）的预测非常重要。考虑更真实的阵风，考虑接近的湍流，因此不仅考虑阵风的特征长度和时间尺度，而且考虑进入湍流边界层的特征长度和时间尺度。应用涡解模拟（LES）代替通常使用的无粘或基于RANS的预测，以便在适当考虑所有相关空间和时间尺度的情况下获得更真实、更可靠的结果。此外，在确定尺寸时，决定性因素是考虑紊流阵风对结构施加的真实的局部载荷，而不是对升力或阻力系数等积分量的约束。强耦合流固耦合流固耦合数值模拟在阵风作用下的扩展。到目前为止，这种情况在土木工程中还没有研究过，但对于确定结构的可能损坏具有决定性意义。

The objective of the present project is to develop a methodology to efficiently simulate and analyze the effect of strong turbulent wind gusts on flexible lightweight structures. For the design and dimensioning of these constructions the highly dynamic interaction between rather rare but very strong gusts and the structure is the crucial factor that decides on survival and stability. Compared to these extreme loads, flows described by a standard atmospheric turbulent boundary layers are of little relevance for the dimensioning, robustness and durability. For the latter scenario huge efforts have been made in the past years for developing coupledfluid-structure interaction (FSI) simulation tools allowing to investigate the interaction of flexible structures with turbulent flows. However, the load case where single or multiple wind gusts hit a flexible structure leading to extreme loads has been considered only to a small extent in the literature so far. The proposal aims to Close this gap by developing a simulation strategy which allows to tackle such coupled and highly dynamic physical processes in an efficient manner. The considered length and time scales are restricted to local windevents occurring in the micro scale.Thus the main objectives and resulting benefits are:- The development of a methodology which generates individual wind gusts or a series of such events by an injection within the computational domain and close to the object of interest. Thedesign of the methodology based on a source-term formulation should especially consider the feedback effect of the structure and the resulting turbulent flow on the wind gust itself. It is of major importance for highly turbulent flows and their prediction via large-eddy simulations (LES).- The consideration of more realistic wind gusts taking the approaching turbulent flow and thus not only the characteristic length and time scale of the gust but also the characteristiclength and time scales of the incoming turbulent boundary layer into account.- The application of eddy-resolving simulations (LES) instead of often used inviscid or RANS-based predictions in order to achieve more realistic and more reliable results taking allrelevant spatial and temporal scales appropriately into account. Furthermore, for the dimensioning it is decisive to consider real local loads on the structures imposed by the turbulent wind gusts instead of the constraint to integral quantities suchas lift or drag coefficients.- The extension towards strongly coupled FSI simulations for lightweight structures subjected to turbulent wind gusts. This scenario was not investigated in civil engineering up to now but is decisive to determine possible damages of the structure.