Output feedback control of flow on a flat plate past a leading edge using plasma actuators
(English)In: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385XArticle in journal (Refereed) Accepted
The evolution and control of a two dimensional (2D) wavepacket developing on a flat plate with a leading edge is investigated by means of direct numerical simulation (DNS).
The aim is to identify and suppress the wavepackets generated by freestream perturbations. A sensor is placed close to the wall in order to detect the upcoming wavepacket, while an actuator is placed further downstream to control it. A plasma actuator is modelled as an external forcing on the flow using a model based and validated on experimental investigations. A Linear Quadratic Gaussian (LQG) controller is designed and an output projection is used to build the objective function. Moreover, by appropriate selection of the Proper Orthogonal Decomposition (POD) modes, we identify the disturbances to be damped. A reduced-order model of the input-output system is constructed by using system identification via the Eigensystem Realization Algorithm (ERA) algorithm.
A limitation of the plasma actuators is the uni-directional forcing of the generated wall jet, which is predetermined by the electrodes location. In this paper, we address this limitation by proposing and comparing two different solutions: i) by introducing an offset in the control signal such that the resulting total forcing is oriented along one direction; ii) by using two plasma actuators acting in opposite directions. The results are compared with the ideal case where constraints are not accounted for the control design. We show that the resulting controllers based on plasma actuators can successfully attenuate the amplitude of the wavepacket developing inside the boundary layer.
Other Engineering and Technologies not elsewhere specified
IdentifiersURN: urn:nbn:se:kth:diva-117914OAI: oai:DiVA.org:kth-117914DiVA: diva2:603868
QP 20132013-02-072013-02-072013-05-31Bibliographically approved