In this work, we perform direct numerical simulations of leading-edge momentum injection of a NACA0009 airfoil at poststall angles of attack. It is found that the lift response is highly dependent upon the instantaneous state of the wake at the time of actuation, which is characterized by the phase of the vortex-shedding limit cycle present in the unactuated system. In particular, we find that actuating at a phase of the limit cycle corresponding to the maximum lift gives the largest maximum in transient lift response, whereas actuating near the lift minimum gives a smaller initial transient lift enhancement and can lead to a significant reduction in the amplitude of the limit cycle. As well as characterizing this phase dependency, we develop a reduced-order model that can capture this behavior. This is achieved by applying dynamic mode decomposition with control to a concatenation of velocity and lift measurements from several training datasets. The resulting models can accurately capture the dynamics of the training datasets as well as for phases not included in the training data. We show that for this method of actuation, multiple control objectives with the same actuator can be achieved.
Modeling the Flow State Sensitivity of Actuation Response on a Stalled Airfoil
AIAA Journal ; 59 , 8 ; 2901-2915
2021-04-26
15 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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