Observers and feedback control for shear layer vortices

The stirring motion of shear layer vortices plays a prominent and often critical role in diverse engineering applications. Periodic zero net flow actuation is an established mechanism to effect shear layer instability and growth. Active feedback control is considered here as a means to regulate and maximize shear layer mixing: Feedback utilizes estimated vortex locations to harmonize actuation with vortex release. We propose an observer structure based on a phenomenological dynamic phasor model for the travelling waveform of sensors' readings, and illustrate its use in simulations and open and closed loop experiments with the backward facing step system, and in free shear layer simulations.