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Closed-Loop Control of Vortex Shedding on a Two-Dimensional Flat-Plate Airfoil at a Low Reynolds Number

Joe, Won Tae and Taira, Kunihiko and Colonius, Tim and MacMynowski, Douglas G. and Tadmor, Gilead (2008) Closed-Loop Control of Vortex Shedding on a Two-Dimensional Flat-Plate Airfoil at a Low Reynolds Number. In: 46th AIAA Aerospace Sciences Meeting and Exhibit, 7-10 January 2008, Reno, NV.

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Open- and closed-loop control of vortex shedding in two-dimensional flow over a flat plate at high angles of attack is numerically investigated at a Reynolds number of 300. Unsteady actuation is modeled as a body force near the leading or trailing edge, and is directed either upstream or downstream. For moderate angles of attack, sinusoidal forcing at the natural shedding frequency results in phase locking, with a periodic variation of lift at the same frequency. However, at sufficiently high angles of attack, subharmonics of the forcing frequency are also excited and the average lift over the forcing period varies from cycle to cycle in a complex manner. It is observed that the periods with the highest averaged lift are associated with particular phase difference between the forcing and the lift. We design a feedback algorithm to lock the forcing with the phase shift associated with the highest period-averaged lift. It is shown that the compensator results in a stable phaselocked limit cycle for a larger range of forcing frequencies than the open-loop control, and that it is able to stabilize otherwise unstable high-lift limit cycles that cannot be obtained with open-loop control. For example at an angle of attack of 40°, the feedback controller can increase the averaged lift coefficient from 1.35 to 2.43, an increase of 80%.

Item Type:Conference or Workshop Item (Paper)
Related URLs:
URLURL TypeDescription Paper Paper
Taira, Kunihiko0000-0002-3762-8075
Colonius, Tim0000-0003-0326-3909
MacMynowski, Douglas G.0000-0003-1987-9417
Additional Information:© 2008 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Published Online: 19 Jun 2012. Work supported by a Multidisciplinary Research Initiative from the United States Air Force Office of Scientific Research (FA9550-05-1-0369, Program Manager: Dr. Fariba Fahroo).
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-05-1-0369
Subject Keywords:Aerospace Systems, Operations and Life Cycle
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Other Numbering System NameOther Numbering System ID
AIAA Paper2008-634
Record Number:CaltechAUTHORS:20190717-102318299
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97196
Deposited By: Melissa Ray
Deposited On:18 Jul 2019 16:43
Last Modified:16 Nov 2021 17:29

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