FEEDBACK CONTROL OF GLOBALLY UNSTABLE FLOWS: IMPINGING SHEAR FLOWS
Global oscillations of impinging shear flows are excited by a fluid-dynamic feedback mechanism, by means of which the distortion of the vorticity field upon impingement is fed back upstream to the separation location. It is shown that these global oscillations can effectively be suppressed, without destabilizing other modes, by actively cancelling the effect of the fluid-dynamic feedback. This is achieved with the aid of loudspeakers, focused on the upstream separation edge only and activated by a transducer measuring the flow response. With the aid of an adaptive digital controller, it was possible to eliminate the flow oscillation altogether, even at transitional test conditions at which the flow oscillations could occur at one or the other of two possible modes.
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Supplemental Notes:
- J Fluids and Structures, v 9 n 8, Nov 1995, p 907 [23 p, 21 ref, 17 fig]
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Authors:
- Ziada, S
- Publication Date: 1995
Language
- English
Subject/Index Terms
- TRT Terms: Feedback control; Flow; Oscillation; Shear rate
- Uncontrolled Terms: Feedback; Shear flow
- Old TRIS Terms: R
- Subject Areas: Marine Transportation;
Filing Info
- Accession Number: 00718966
- Record Type: Publication
- Source Agency: British Maritime Technology
- Files: TRIS
- Created Date: Mar 27 1996 12:00AM