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Published August 2011 | public
Journal Article

Closed-Loop Control of Lift for Longitudinal Gust Suppression at Low Reynolds Numbers

Abstract

Experiments are conducted to investigate the ability of variable-pressure pulsed-blowing actuation to maintain a constant lift force on a low-aspect-ratio semicircular 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 system identification methods. Robust closed-loop controllers are synthesized using a mixed-sensitivity loop-shaping approach. An additional feedforward disturbance compensator is designed based on a model of the unsteady aerodynamics. The controllers show suppression of lift fluctuations at low gust frequencies, f < 0.8 Hz(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 flowfield that leads to enhanced lift on the wing.

Additional Information

© 2011 Wesley Kerstens. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Presented as Paper 2010-4969 at the 5th Flow Control Conference, Chicago, IL, 28 June–1 July 2010; received 23 September 2010; revision received 14 January 2011; accepted for publication 5 March 2011. The support for this work by the U.S. Air Force Office of Scientific Research (AFOSR) Multidisciplinary University Research Initiative (FA9550-05-0369) with program manager Fariba Fahroo and AFOSR grant (FA9550-09-1-0189) monitored by Doug Smith is gratefully appreciated. David Williams gratefully acknowledges partial support from the Alexander von Humboldt foundation. The authors also acknowledge partial support from the Illinois NASA Space Grant Consortium for Wesley Kerstens and support from the German Science Foundation for Jens Pfeiffer.

Additional details

Created:
August 19, 2023
Modified:
October 24, 2023