CLOSED-LOOP CONTROL GUST SUPPRESSION AT OF LIFT FOR LONGITUDINAL LOW REYNOLDS NUN4BERS Kerstens, Wesley Experiments are conducted to investigate the ability of variable pressure, pulsed-blowing actuators and zero-net-mass-flux actuators to maintain a constant lift force on a low aspect ratio, semi-circular wing in a longitudinally gusting flow. Dynamic models of the lift response to actuation and the lift response to longitudinal gusting are obtained through modern black-box system identification methods. Robust, H∞, closed-loop controllers are synthesized using a mixed sensitivity, loopshaping approach. An additional feed-forward disturbance compensator is designed based on a model of the unsteady aerodynamics. The controllers show suppression of lift fluctuations at low gust frequencies, f < 1Hz (reduced frequency, k < 0.09). At higher frequencies, the control performance degrades due to limitations related to the time for a disturbance, created by the actuators, to convect over the wing and establish the flow field that leads to enhanced lift on the wing. Similar limitations are observed for both wings even though the bandwidth of the zero-net-mass-flux actuators is an order of magnitude higher than that of the pulsed-blowing actuators. M.S. in Mechanical and Aerospace Engineering, July 2011 Williams, David R. 2011-07-26 2011-07 Thesis application/pdf islandora:7272 http://hdl.handle.net/10560/2354 MMAE / Mechanical, Materials, and Aerospace Engineering Illinois Institute of Technology en In Copyright http://rightsstatements.org/page/InC/1.0/ Restricted Access