A Caltech Library Service

Control of a Semi-Circular Planform Wing in a "Gusting" Unsteady Freestream Flow: I - Experimental Issues

Williams, David R. and Collins, Jesse and Tadmor, Gilead and Colonius, Tim (2008) Control of a Semi-Circular Planform Wing in a "Gusting" Unsteady Freestream Flow: I - Experimental Issues. In: 38th Fluid Dynamics Conference and Exhibit, 23-26 June 2008, Seattle, WA.

[img] PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


Active flow control is used to modify the lift, drag and pitching moments on a semicircular wing during "gusting" flow conditions. A longitudinal oscillating flow component has an amplitude of 10 percent of the freestream speed and a frequency giving k = 0.048 (f = 0.2 Hz). The aspect ratio of the wing is AR = 2.54, and the chord Reynolds number of the wing is 70,600. Pulsed-blowing flow control actuation occurs along the leading edge of the airfoil via 16 spatially localized micro-valve actuators. Feed-forward control based on a quasi-steady lift model is used to stabilize lift fluctuations generated by an oscillating free stream, which simulates the longitudinal component of a gusting flow. The quasi-steady system model reduces the amplitude of the fundamental and first harmonics of lift oscillations, but does not account for time delays. The time delay between the lift and the freestream oscillation was measured to be τ_(u)^(+) = 4.8. The time delay between the lift and the actuator input signal was found to be τ_(a)^(+) = 11.3.

Item Type:Conference or Workshop Item (Paper)
Related URLs:
URLURL TypeDescription Paper Paper
Colonius, Tim0000-0003-0326-3909
Additional Information:© 2008 by David R. Williams. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Published Online: 15 Jun 2012. The support for this work by the U.S. Air Force Office of Scientific Research MURI (FA9550-05-0369) with program manager Dr. Fariba Fahroo is gratefully appreciated. We also acknowledge the support from the Illinois NASA Space Grant Consortium for partial support of Jesse Collins.
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-05-0369
Subject Keywords:Fluid Dynamics
Other Numbering System:
Other Numbering System NameOther Numbering System ID
AIAA Paper2008-3976
Record Number:CaltechAUTHORS:20190717-102319947
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97210
Deposited By: Melissa Ray
Deposited On:18 Jul 2019 16:24
Last Modified:16 Nov 2021 17:29

Repository Staff Only: item control page