Influence of Reynolds number on the fluid–structure interaction characteristics of vertical-axis wind turbine blades under parking conditions

Abstract

With the increasing scale of vertical-axis wind turbines (VAWTs), the aeroelastic behavior of long and flexible blades poses significant challenges to their structural dynamics. To investigate these effects, a two-way fluid–structure coupling approach was employed using a single VAWT blade under standstill conditions (0° angle of attack). Simulations across various Reynolds numbers (Re) revealed that the dominant vibration modes were flapwise and edgewise, concentrated in low-order modes, while torsional vibration appeared only in higher-order modes. Periodic oscillations of lift and drag were driven by structural vibrations. As Re increased, the blade’s dynamic response evolved from a single mode to multiple coupled modes, with new frequency components aligned with the inflow direction showing characteristics of first-order flapwise motion. At high Re, intensified aerodynamic load fluctuations induced multimodal coupling and more complex responses, highlighting pronounced aeroelastic instability.