Passive Flow Control Behaviour of Vertical Axis Hydrokinetic Turbine Darrieus Type: a Numerical Study of Single Blade

The behavior of passive flow control mechanisms on a single blade of a Darrieus-type Vertical Axis Hydrokinetic Turbine (VAHT) were investigated using CFD. Flap configurations positioned at 30%, 50%, and 75% chord lengths were evaluated, with a maximum opening angle of 45°. The movement of the flap, driven by flow-induced forces, was modeled based on experimental observations at an inlet velocity of 0.29 m/s. Results indicate that the flap at 30% chord position demonstrated superior performance, with a 41% increase in lift coefficient at critical azimuthal angles, effectively delaying stall. The findings emphasize the potential of passive flap mechanisms to enhance turbine performance under varying operational conditions, providing a foundation for further innovations in hydrokinetic turbine design. The integration of experimental validation and CFD analysis ensures the reliability of results, contributing to the optimization of blade-level flow dynamics in renewable energy applications.