Feasibility Studies of Spoiler and Aileron Control Systems for Large Horizontal-Axis Wind Turbines

Abstract

Studies have been conducted to determine the feasibility of using aileron or spoiler controls as alternates to pitch control for large horizontal axis wind turbines. The NASA MOD-O machine was used as the basis for this study. Results of the study show that either ailerons or spoilers can provide control necessary to limit turbine power in high wind conditions. An aileron system is recommended for the present application, based upon the ability of ailerons to provide self-starting and added power at low wind speed conditions. The preliminary design study including aileron component sizing and maximum hinge moments was completed and ailerons will be fabricated for testing on the MOD-O turbine. Nomenclature c = airfoil or blade local section chord C p -rotor power coefficient, power/ Vip V 3 irR 2 R = maximum blade radius V = wind velocity x = spanwise distance from center of rotor X = tip speed ratio, uR IV d a = aileron deflection angle, positive down (upwind) d s = aileron deflection angle, positive up (downwind) a; = rotor angular velocity

Ultimate and fatigue load mitigation by an inertial-driven passive flap, using a geometrically exact multibody formulation

“…The steady sectional hinge aerodynamic derivatives are estimated with the ESDU semi-empirical method (ESDU 89010, 1989) and parameterized as functions of angle of attack and flap deflection. Post-stall corrections due to control surface deflection are computed according to the WSU model (Wentz et al, 1980). Non-circulatory coefficients are included according to the theory of Theodorsen (Theodorsen, 1942;Bottasso et al, 2016a).…”