Feedback Control of Spatially Evolving Flows
2007 (English)Licentiate thesis, comprehensive summary (Other scientific)
In this thesis we apply linear feedback control to spatially evolving flows in order to minimize disturbance growth. The dynamics is assumed to be described by the linearized Navier--Stokes equations. Actuators and sensor are designed and a Kalman filtering technique is used to reconstruct the unknown flow state from noisy measurements. This reconstructed flow state is used to determine the control feedback which is applied to the Navier--Stokes equations through properly designed actuators. Since the control and estimation gains are obtained through an optimization process, and the Navier--Stokes equations typically forms a very high-dimensional system when discretized there is an interest in reducing the complexity of the equations. One possible approach is to perform Fourier decomposition along (almost) homogeneous spatial directions and another is by constructing a reduced order model by Galerkin projection on a suitable set of vectors. The first strategy is used to control the evolution of a range of instabilities in the classical family of Falkner--Skan--Cooke flows whereas the second is applied to a more complex cavity type of geometry.
Place, publisher, year, edition, pages
Stockholm: KTH , 2007. , v, 104 p.
Trita-MEK, ISSN 0348-467X ; 2007:03
Stability, Control, Estimation, Absolute/Convective instabilities, Model reduction
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-4283OAI: oai:DiVA.org:kth-4283DiVA: diva2:11620
2007-03-08, S40, Teknikringen 8, Tekniska Högskolan, Valhallavägen, 10:30
Berggren, Martin, Universitetslektor
Henningson, Dan StefanBrandt, Luca
QC 201011222007-02-222007-02-222010-11-22Bibliographically approved
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