Stability of helical vortex structures shed from flexible rotors

The presented investigation is motivated by the need to uncover connections between underlying rotor fluid-structure interactions and vortex dynamics fatigue performance characterization of flexible blades, their hub, supporting superstructure. Towards this effort, temporal stability characteristics tip vortices shed from blades are investigated numerically. An aeroelastic free-vortex wake method employed simulate helical associated velocity field. A linear eigenvalue analysis quantify trends (growth rate v. perturbation wavenumber) growth-rate evolution vortices. Simulations a canonical with rigid its generation first conducted validate herein. Next, stationary wind turbine emulated using National Renewable Energy Laboratory 5MW reference base design investigate impact aeroelasticity has on in time. Blade flexibility shown reduce sensitivity destabilization low wavenumber perturbations, also blade-pitch reduces magnitude alters peak dependence wavenumber, all which have past not been reported rotorcraft literature. current aims develop insight into kinematics work towards quantifying loading effects, minimizing adverse blade-vortex interaction such as excessive noise emission large blade vibrations affecting performance.