Flow control using the parabolized stability equations

Abstract

This project deals with the active, closed-loop control of flows, with the objective of reducing the fluctuations of the fluidic variables at a given objective position. It is made use of the parabolized stability equations in order to construct reduced-order models in the form of transfer functions which are then able to reproduce both the open-loop behaviour of the system, along with the effect of an actuator. Two classes of problems will be evaluated; Sheared flows, mixing layers and turbulent jets, which have an aeroacoustic appeal, given that the objective of the control law is related to the reduction of acoustic emissions to the far-field. The second type of problem corresponds to boundary layers, in two and three dimensions. For this case, the control has the main objective of postponing the transition to turbulence, maintaining the flow in a laminar condition and, therefore, leading to a reduction in the friction drag coefficient. The focus of this work lies on the definition of the control laws and modelling of the systems, whereas the implementation of the techniques in the respective non-linear systems, whether these are made via simulation or experiment, will be realized in a partnership with other research groups. (AU)