Model reduction and control of a cavity-driven separated boundary layer

Espen Akervik (1) , Jérôme Hoepffner (2) , Uwe Ehrenstein (2) , Dan S. Henningson (1)

1 Linné FLOW Center [Stockholm]
2 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre

The control of a globally unstable boundary-layer flow along a two-dimensional cavity is considered. When perturbed by the worst-case initial condition, the flow exhibits a large transient growth associated with the development of a wave packet along the cavity shear layer followed by a global cycle related to the least stable global eigenmodes. The flow simulation procedure is coupled to a measurement feedback controller, which senses the wall shear stress at the downstream lip of the cavity and actuates at the upstream lip. A reduced model for the control optimization is obtained by a projection on the least stable global eigenmodes. The LQG controller is run in parallel to the Navier-Stokes time integration. It is shown that the controller is able to damp out the global oscillations.

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Espen Akervik, Jérôme Hoepffner, Uwe Ehrenstein, Dan S. Henningson. Model reduction and control of a cavity-driven separated boundary layer. IUTAM Symposium on Flow Control and Mems, Sep 2006, Royal Geog Soc. London, United Kingdom. pp.147-155. ⟨hal-00420783⟩