Control of a separated boundary layer: reduced-order modeling using global modes revisited

• DOI: 10.1007/s00162-010-0195-5
• Publication Date: 2010-03-17T15:52:30Z
• Authors: Uwe Ehrenstein; Pierre-Yves Passa...; Franois Gallaire
• Keywords: Oblique projection; Basis (linear algebra)

The possibility of model reduction using global modes is readdressed, aiming at the controlling of a globally unstable separation bubble induced by a bump geometry. A combined oblique and orthogonal projection approach is proposed to design an estimator and controller in a Riccati-type feedback setting. An input-output criterion is used to appropriately select the modes of the projection basis. The full-state linear instability dynamics is shown to be successfully controlled by the feedback coupling with controllers of moderate degrees of freedom.