Date of Award
2026
Document Type
Open Access Dissertation
Degree Name
Doctor of Philosophy in Mechanical Engineering-Engineering Mechanics (PhD)
Administrative Home Department
Department of Mechanical and Aerospace Engineering
Advisor 1
Fernando Ponta
Committee Member 1
Loenard Bohmann
Committee Member 2
Ana Dyreson
Committee Member 3
Kazuya Tajiri
Abstract
In recent trends, wind turbine rotor diameters have been growing in size to reduce their associated levelized cost of energy. To keep these large blades lightweight in design, reductions in structural mass are made, which make them more flexible and aeroelastically sensitive to atmospheric flow variations that cause fluctuating rotor loads. Additionally, utility scale wind farms have expanded to contain larger-scale, coherent structures in atmospheric flow that propagate throughout the farm and mutually advect with wind turbine vortex-wakes. Thus, predictions of the aeroelastic response of wind turbines and the vortex structures generated in their wakes require a robust representation of the naturally variant wind conditions in which they operate.
This dissertation uses numerical simulations to examine wind turbine operation in variant inflow conditions, and presents a novel method for modeling propagating coherent structures within wind farm flow. The proposed atmospheric characterization model is developed to enable more detailed simulations of wind turbine vortex-wake evolutionary dynamics through a parametrically defined, Spatio-Temporally Variable (STV) representation of wind inflow, and is implemented within an existing multi-physics wind turbine model called the Common Ordinary Differential Equation Framework (CODEF).
Initial analyses presented in this dissertation establish how changes to rotor flexibility and varying wind inflow conditions affect blade aeroelastic response and loading conditions, and thus influence the formation and subsequent evolution of vortex structures within the downstream wake. Then, an outline of the proposed STV atmospheric modeling method is described, and its unique advantages are demonstrated with analysis of CODEF simulation results. STV simulations are first used to demonstrate the isolated effects of spatial variations in wind parameters on turbine aeroelastic response and vortex-wake evolution. STV atmospheric characterization methods are then applied to represent observed spatial and temporal variations in inflow conditions measured at a real wind farm, and validated against LiDAR wake velocity measurements to demonstrate the proposed method's capabilities in modeling wake transitions resulting from localized and transient fluctuations in wind, and propagating coherent flow structures, which traditionally averaged wind input approaches struggle to represent.
Recommended Citation
Farrell, Alayna, "Analysis and Modeling of the Effects of Atmospheric Flow Fluctuations on Wind Turbine Rotor Aeroelastic Response and Vortex-Wake Evolution", Open Access Dissertation, Michigan Technological University, 2026.
https://digitalcommons.mtu.edu/etdr/2132
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