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量化结构的影响。对于这些建筑的设计和尺寸，非常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的关键因素。与这些极端载荷相比，标准大气湍流边界层所描述的流动与尺寸、稳健性和耐久性几乎没有关系。对于后一种情况，在过去的几年里，人们已经做出了巨大的努力来开发耦合流固耦合（FSI）模拟工具，以研究柔性结构与湍流的相互作用。然而，迄今为止，文献中对单次或多次阵风冲击柔性结构导致极端荷载的荷载情况考虑较少。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仅限于发生在微观尺度上的局部风事件。因此，主要目标和由此带来的好处是：-开发一种方法，通过在计算域内和感兴趣的对象附近注入产生单个阵风或一系列此类事件。基于源项公式的方法设计应特别考虑结构和由此产生的湍流对阵风本身的反馈效应。这对高湍流流场及其大涡模拟预报具有重要意义。-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，而且考虑来风湍流边界层的特征长度和时间尺度。-应用涡流解析模拟（LES），而不是经常使用的无粘性或基于ranss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现实和更可靠的结果。此外，在确定尺寸时，考虑湍流阵风对结构施加的实际局部载荷而不是升力或阻力系数等积分量的约束是决定性的。-扩展到受湍流阵风影响的轻型结构的强耦合FSI模拟。到目前为止，土木工程还没有对这种情况进行研究，但它对确定结构的可能损害具有决定性作用。

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.