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Accueil > Evénements Scientifiques > Conférences et Séminaires > Conférences et Séminaires 2010 > Séminaire du Pr Dan HENNINGSON 15 juin 2010

Séminaire du Pr Dan HENNINGSON 15 juin 2010

9 juin 2010

INPUT-OUTPUT ANALYSIS AND FLOW CONTROL APPLIED TO THE BLASIUS BOUNDARY LAYER
15 juin 2010 à 10h.
Amphithéâtre Nougaro
Pr Dan HENNINGSON, Linné FLOW Center, KTH Mechanics, Stockholm.

Résumé :
The attenuation of three-dimensional wavepackets of streaks and Tollmien-Schlichting (TS) waves in a transitional flat-plate using feedback control is investigated numerically. An array (about 10–20) of localized sensors and actuators with compact spatial support are distributed near the rigid wall equidistantly in the homogenous spanwise direction and connected to a low-dimensional (r = 60) LQG–controller. The control objective is to minimize the disturbance energy in a domain spanned by a number of proper orthogonal decomposition (POD) modes. The feedback controller is based on a reduced-order model of the linearized Navier-Stokes equations including the inputs and outputs, computed using a snapshot-based balanced truncation method. It is demonstrated that the linear controller using relatively few sensors and actuators reduces the energy growth of TS wavepackets and the streaks substantially and efficiently. The robustness of the controller is investigated by varying the number of actuators and sensors, the Reynolds number and the pressure gradient. This work constitutes the first experimentally feasible simulationbased control design using localized sensing and acting devices in conjunction with linear control theory in a three-dimensional setting.