Aerodynamic modeling of wind turbine blade considering bending deformation: A modified vortex cylinder model

With the increasing size and flexibility of modern wind turbine blades, blade bending deformation has become more pronounced, making its aerodynamic effects non-negligible. This study investigates the aerodynamic impact of blade bending deformation and proposes a modified vortex cylinder model considering bending deformation (VC-BD). Compared to the blade element momentum, lifting line method (LLM), and high-fidelity computational fluid dynamics (CFD) methods, the VC-BD model captures both geometric and wake-induced effects induced by blade bending and responses more accurately under various bending conditions. A vortex-theoretical analysis identifies two main categories of bending-induced aerodynamic effects: geometric changes altering local angle of attack and loading, and aerodynamic induction effects involving bound vortex self-induction, wake redistribution, and trajectory distortion. The proposed VC-BD model accurately captures the aerodynamic effects of blade bending, showing strong agreement with CFD and LLM results while maintaining a favorable balance between fidelity and computational cost. It provides a practical and efficient tool for early-stage design and aeroelastic analysis of flexible blades.