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

• Applicant: Professor Dr.-Ing. Michael Breuer
• Subject Area: Fluid Mechanics
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 435252632

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.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Guillaume De Nayer