“Wind tunnel experiments were conducted at Rensselaer Polytechnic Institute's Center for Flow Physics and Control's subsonic wind tunnel, which experimentally quantified the aerodynamic performance of the S817 airfoil. This study has two main thrusts: Experimentally evaluate common aerodynamic properties of the S817 airfoil, and develop flow control strategies using continuously actuated and pulse‐modulated synthetic jets for future field testing to show the reduction of unsteady loading and increased aerodynamic performance. Quasi‐2D and finite span 3D configurations were utilized, where integrated aerodynamic loading, surface pressure, and stereoscopic particle image velocimetry data were collected to quantify the overall aerodynamic performance and stall characteristics of this airfoil. Experiments showed that synthetic jets, located at x/c=0.35 and angled at 45° with respect to the surface, increased the lift curve slope by 3.8%, the maximum lift coefficient by 10.5%, increased the L/D by as much as 39% at high angles of attack and delayed the stall angle of attack by 3°. Global particle image velocimetry measurements quantified the flowfield and showed flow reattachment could be achieved at various angles of attack using flow control where the flow would otherwise be separated. Near field measurements of the synthetic jet orifice yielded insight as to how synthetic jets interact with the cross‐flow in the time‐ and phase‐averaged sense. For very high angles of attack, a pulsed modulation technique was implemented, demonstrating flow reattachment in scenarios where a sinusoidal synthetic jet actuation scheme was unable to reattach the flow, with the benefit of achieving this with lower energy consumption compared with sinusoidal actuation.”
Wind Energy, vol. 21, no. 10, pp. 823–836, February 2018.