Feedback-controlled forcefully attached flow on a stalled airfoil

Philipp Tewes, Israel J Wygnanski, Anthony E. Washburn

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Active maintenance of attached flow at natural poststall conditions requires a small intervention, relative to the one needed to force a separated flow to reattach under the same conditions. Experiments with slot suction applied near the leading edge of a stalled airfoil revealed a hysteresis of lift and drag that depends on the level of suction. This offers an opportunity to keep the flow attached at minimum input levels while guaranteeing that flow separation will not be allowed to occur. A simple approach was adopted that uses a rapidly responding pressure sensor located near the leading edge or in the interior reservoir of the airfoil for feedback control. The proposed controller used a prescribed pressure coefficient to keep the flow attached. Since a dimensionless pressure coefficient is required for this purpose, two similar sensors were installed in the pitot-static tube that monitored the freestream velocity. The impact of the time delay on the stability of the controller was briefly discussed and accounted for. The robustness of the controller was demonstrated under varying freestream velocities.

Original languageEnglish (US)
Pages (from-to)940-951
Number of pages12
JournalJournal of Aircraft
Volume48
Issue number3
DOIs
StatePublished - May 2011

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Airfoils
Feedback
Controllers
Flow separation
Pressure sensors
Robustness (control systems)
Feedback control
Drag
Hysteresis
Time delay
Sensors
Experiments

ASJC Scopus subject areas

  • Aerospace Engineering

Cite this

Feedback-controlled forcefully attached flow on a stalled airfoil. / Tewes, Philipp; Wygnanski, Israel J; Washburn, Anthony E.

In: Journal of Aircraft, Vol. 48, No. 3, 05.2011, p. 940-951.

Research output: Contribution to journalArticle

Tewes, Philipp ; Wygnanski, Israel J ; Washburn, Anthony E. / Feedback-controlled forcefully attached flow on a stalled airfoil. In: Journal of Aircraft. 2011 ; Vol. 48, No. 3. pp. 940-951.
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