Desenvolvimento de uma metodologia aerodinâmica e estrutural para análises de problemas de interação fluido estrutura em turbinas eólicas de eixo horizontal

Abstract

This thesis proposes a comprehensive approach for evaluating the structural and aerodynamic behavior of wind turbine blades, with an emphasis on fluid-structure interaction (FSI), based on advanced numerical techniques. Initially, modal analysis were conducted on two similar blade geometries, distinguished by their structural properties: one modeled using three-dimensional solid elements with homogenized equivalent sections, and the other using stratified shell elements (layers), accounting for the anisotropic nature of composite materials. The extracted natural frequencies and vibration modes were validated against the literature, with the first torsional mode being captured exclusively in the shell-based model. Subsequently, computational fluid dynamics (CFD) simulations were performed, coupled with distinct rotational modeling strategies — stationary reference frame with implicit rotation (MRF) and sliding mesh technique (AMI) — to accurately capture the transient phenomena associated with non-uniform flow over the rotor. The analyses of thrust and torque under varying wind intensities and turbulence regimes demonstrated consistency with experimental data and provided a basis for the informed selection of the appropriate kinematic model depending on the application. Finally, two FSI coupling configurations were investigated: (i) a fixed, isolated blade subjected to turbulent wind, aimed at characterizing its time-dependent deflection and dynamic response; and (ii) a simplified rotor undergoing simultaneous rotation and deformation induced by the flow, employing a mesh coupling methodology under compound motion. The numerical results obtained, supported by literature benchmarks and qualitative assessments, demonstrate the robustness of the adopted modeling strategy and reinforce the relevance of fluid-structure interaction in enhancing the structural and aeroelastic performance of modern wind turbines employing composite materials.