Novel Vertical Axis Wind Turbine Flow Control: Adaptive Flaps and Trailing-edge Splitter

Dynamic stall occurring the operation of vertical axis wind turbine (VAWT) have attracted great attention in the field of wind power due to their detrimental effects on aerodynamic performance. Extensive flow control strategies have been conducted to alleviate the adverse effects of dynamic stall on aerodynamic performance. This study proposed the active control of adaptive flaps and innovatively introduced a trailing-edge splitter plate as a control method to improve the aerodynamic performance of VAWT. A computational fluid dynamics (CFD) simulation is conducted to investigate the influence of two flow control methods on the aerodynamic performance of a National Advisory Committee for Aeronautics (NACA) 0015 airfoil and a VAWT. The findings indicate that the adaptive flap should be positioned at the trailing edge. An optimal deployment angle exists across various angles of attack (AOA), with the flap length of 0.15c determined as most effective for flow separation control at moderate Reynolds numbers. In pre-stall, the splitter plate achieves a maximum lift-drag ratio improvement of approximately 61.6% (l = 0.2c). Regarding the application effects of both flow control methods on the VAWT, the flaps can significantly reduce the vortex size near the blades and promote vortex shedding near the blades. At λ = 1.2-2.0, the flaps can improve the power coefficient factor of the VAWT by up to 42.5% (λ = 1.6).The splitter plate can increase the power coefficient of the VAWT by a maximum of about 29.4% (λ = 0.8) at low TSRs (λ = 0.4 to 1.2). At high TSRs (λ = 2.0 to 2.4), the splitter plate can increase the power coefficient by a maximum of about 25.8% (λ = 2.8).