Linear feedback control and estimation applied to instabilities in spatially developing boundary layers
2007 (English)In: Journal of Fluid Mechanics, ISSN 0022-1120, E-ISSN 1469-7645, Vol. 588, 163-187 p.Article in journal (Refereed) Published
This paper presents the application of feedback control to spatially developing boundary layers. It is the natural follow-up of Hogberg & Henningson (J. Fluid Mech. vol. 470, 2002, p. 151), where exact knowledge of the entire flow state was assumed for the control. We apply recent developments in stochastic models for the external sources of disturbances that allow the efficient use of several wall measurements for estimation of the flow evolution: the two components of the skin friction and the pressure fluctuation at the wall. Perturbations to base flow profiles of the family of Falkner-Skan-Cooke boundary layers are estimated by use of wall measurements. The estimated state is in turn fed back for control in order to reduce the kinetic energy of the perturbations. The control actuation is achieved by means of unsteady blowing and suction at the wall. Flow perturbations are generated in the upstream region in the computational box and propagate in the boundary layer. Measurements are extracted downstream over a thin strip, followed by a second thin strip where the actuation is performed. It is shown that flow disturbances can be efficiently estimated and controlled in spatially evolving boundary layers for a wide range of base flows and disturbances.
Place, publisher, year, edition, pages
2007. Vol. 588, 163-187 p.
optimal perturbations, state estimation, flow systems, transition, wall, stability, equations
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-6803DOI: 10.1017/S0022112007007392ISI: 000250675400008ScopusID: 2-s2.0-37749017590OAI: oai:DiVA.org:kth-6803DiVA: diva2:11616
QC 201008302007-02-222007-02-222010-09-23Bibliographically approved