HRT

Abstract

The dynamics and control of disturbances in the spatially evolving boundary layer on a flat-plate are investigated from an input-output viewpoint. From the linearized Navier-Stokes equations with inputs (disturbances and actuators) and outputs (objective function and sensor) controllable, observable and balanced modes are extracted using the snapshot-method and a matrix-free time-stepper approach. A balanced reduced-order model is constructed and shown to capture the input-output behaviour of linearized Navier-Stokes equations. This model is used to design a LQG-feedback controller to suppress the growth of perturbations inside the boundary layer