A morphing segmented concept is proposed herein for future extreme-scale wind turbine systems. The morphing may be accomplished by using segmented blades connected by screw sockets and a tension cable system. At low wind and rotor speeds, the segmented blades are fully tensioned and set at high pitch to ensure start-up and maximum power at low speeds. At high rotor rpm, the cable tension can be...

Dynamic stall is an aerodynamic phenomenon encountered when rotorcraft operate near performance boundaries typical of high-speed or maneuvering flight. The complex, highly non-linear aerodynamics and associated interaction with the structures induce exceptionally high loads, violent vibrations, reduced handling qualities, and a reduction in fatigue life. The prediction of dynamic stall remains ...

Surface pressure data from the National Renewable Energy Laboratory’s “Unsteady Aerodynamics Experiment” were analyzed to characterize the impact of threedimensionality, unsteadiness, and flow separation effects observed to occur on downwind horizontal axis wind turbines (HAWT). Surface pressure and strain gage data were collected from two rectangular planform blades with S809 airfoil crosssect...

Recent developments of the aerodynamics models for the comprehensive analysis CAMRAD II are described, particularly the unsteady aerodynamic models and dynamic stall models, and the free wake geometry calculation. Three models for the unsteady aerodynamic loads in attached flow are implemented: from incompressible thin-airfoil theory, from ONERA EDLIN, and from Leishman-Beddoes. Five dynamic st...

Herein, the pressure-sensitive paint (PSP) was used to quantitatively investigate aerodynamic effect of an alula-like vortex generator, which is a bio-inspired passive flow control structure. The global pressure distributions on upper surface at different angles attack were measured determine strength sectional suction forces wing. An generator equipped leading edge wing enlarged area region (n...

A variable-speed, constant-pitch wind turbine was investigated to evaluate the feasibility of constraining its rotor speed and power output without the benefit of active aerodynamic control devices. A strategy was postulated to control rotational speed by specifying the demanded generator torque. By controlling rotor speed in relation to wind speed, the aerodynamic power extracted by the blades...

The enhanced aerodynamic performance of insects results from an interaction of three distinct yet interactive mechanisms: delayed stall, rotational circulation, and wake capture. Delayed stall functions during the translational portions of the stroke, when the wings sweep through the air with a large angle of attack. In contrast, rotational circulation and wake capture generate aerodynamic forc...

BACKGROUND Unexpected performance degradation occurs in wind turbine blades due to leading edge defect when suffering from continuous impacts with rain drops, hails, insects, or solid particles during its operation life. To assess this issue, this paper numerically investigates the steady and dynamic stall characteristics of an S809 airfoil with various leading edge defects. More leading edge d...

In order to understand the effects of the unsteady aerodynamic excitations in complex flow field on blades, on the basis of the data obtained from the single-stage axial flow compressor, three kinds of exciting forms in the compressor had been studied, including the correlation between excitations and responses in the upstream blade row wake, inlet distortion and rotating stall. Results showed ...