Numerical simulation of turbulent wind gusts and their dynamic effects on flexible structures
Publication date
2026-06-03
Document type
Dissertation
Cumulative Thesis
✅
Author
Advisor
Referee
Manhart, Michael
Granting institution
Helmut-Schmidt-Universität/Universität der Bundeswehr Hamburg
Exam date
2026-05-18
Organisational unit
Publisher
Universitätsbibliothek der HSU/UniBw H
Contains the following part
Part of the university bibliography
✅
File(s)
Language
English
Keyword
Wind gust
Modeling and simulation
Computational fluid dynamics (CFD)
Large eddy simulation (LES)
Fluid–structure interaction (FSI)
Immersed boundary method
High performance computing
Abstract
This thesis investigates numerical strategies for imposing discrete wind gusts within high-fidelity eddy-resolving simulations to enable detailed analyses of their interaction with rigid or flexible structures. The central requirement is to introduce the gust into an already evolving flow field in a physically consistent manner, without violating conservation laws or compromising numerical stability. Toward fulfilling this requirement, the work implements a hierarchy of gust-generation techniques, spanning different levels of physical realism, into a large-eddy simulation fluid solver. These range from idealized prescribed disturbances to mechanically induced gusts generated by numerical counterparts of experimental gust-generation devices. This hierarchy comprises three classes of methods: The prescribed velocity methods (field and split velocity methods), the source-term formulation, and the immersed boundary gust generators.
The first part of the thesis imposes a gust and its motion as a prescribed disturbance using the field velocity method (FVM) and the split velocity method (SVM). Both methods are re-derived in a consistent manner, implemented within the numerical solver, and their connection to the Arbitrary Lagrangian–Eulerian (ALE) formulation and the geometric conservation law (GCL) is clarified. A newly introduced test case demonstrates that the feedback term present in the SVM but absent in the FVM becomes essential for accurately predicting horizontal gust responses, establishing the SVM as the physically consistent choice for subsequent applications. Building on this result, the SVM is applied to an elastically mounted airfoil to investigate its aeroelastic behavior under vertical gusts.
Moving one step closer to a physically inspired gust-generation approach, the thesis employs an existing source-term (ST) formulation to inject a localized disturbance near the structure of interest that subsequently propagates freely through the computational domain. The method is applied to rigid and membranous hemispherical structures in a turbulent boundary layer, enabling the simulations to resolve the aerodynamic forces and, for the flexible membrane, the resulting deformations and tensile stresses in the material during the gust impact.
The final part of the thesis advances toward physically realized gust generation procedures by numerically replicating the operation of wind-tunnel gust generators using the immersed boundary method (IBM). Two experimental configurations are modeled: The rigid vertically moving paddle and the adaptive nozzle with a rotatable upper contour. In both immersed-boundary gust generators (IBGG) developed here, the three-dimensional time-resolved flow field generated by the moving geometry is captured in detail, enabling direct comparison with the available experimental measurements. The IBM is further combined with an ALE-based partitioned approach to simulate the fluid–structure interaction of a flexible T-structure subjected to paddle-generated gusts.
Taken together, the contributions of this thesis present a set of numerical strategies for injecting discrete wind gusts across a wide range of configurations, enabling high-fidelity simulations of their interaction with rigid and flexible structures. These developments broaden the capability of numerical simulations to analyze gust encounters and provide a foundation for future studies involving more complex structures and gust conditions.
The first part of the thesis imposes a gust and its motion as a prescribed disturbance using the field velocity method (FVM) and the split velocity method (SVM). Both methods are re-derived in a consistent manner, implemented within the numerical solver, and their connection to the Arbitrary Lagrangian–Eulerian (ALE) formulation and the geometric conservation law (GCL) is clarified. A newly introduced test case demonstrates that the feedback term present in the SVM but absent in the FVM becomes essential for accurately predicting horizontal gust responses, establishing the SVM as the physically consistent choice for subsequent applications. Building on this result, the SVM is applied to an elastically mounted airfoil to investigate its aeroelastic behavior under vertical gusts.
Moving one step closer to a physically inspired gust-generation approach, the thesis employs an existing source-term (ST) formulation to inject a localized disturbance near the structure of interest that subsequently propagates freely through the computational domain. The method is applied to rigid and membranous hemispherical structures in a turbulent boundary layer, enabling the simulations to resolve the aerodynamic forces and, for the flexible membrane, the resulting deformations and tensile stresses in the material during the gust impact.
The final part of the thesis advances toward physically realized gust generation procedures by numerically replicating the operation of wind-tunnel gust generators using the immersed boundary method (IBM). Two experimental configurations are modeled: The rigid vertically moving paddle and the adaptive nozzle with a rotatable upper contour. In both immersed-boundary gust generators (IBGG) developed here, the three-dimensional time-resolved flow field generated by the moving geometry is captured in detail, enabling direct comparison with the available experimental measurements. The IBM is further combined with an ALE-based partitioned approach to simulate the fluid–structure interaction of a flexible T-structure subjected to paddle-generated gusts.
Taken together, the contributions of this thesis present a set of numerical strategies for injecting discrete wind gusts across a wide range of configurations, enabling high-fidelity simulations of their interaction with rigid and flexible structures. These developments broaden the capability of numerical simulations to analyze gust encounters and provide a foundation for future studies involving more complex structures and gust conditions.
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