Active control of jet mixing

A control law to improve jet flow mixing is presented. The control law employs a pair of actuators at the jet nozzle exit that act on the shear layers near the corners by blowing and subtracting fluid in an anti-symmetric fashion and a sensor downstream or at the nozzle exit with a time delay that measures the pressure difference across the nozzle diameter. A 2-D jet flow is numerically simulated along with massless/mass particles and a passive scalar. The mixing enhancement produced by these controllers is demonstrated visually by snapshots of the vorticity, streaklines, particle distribution and scalar field. Probability function for the particles and the scalar field are constructed, which serve as an index of mixing quality and the effectiveness of the controllers. This closed-loop control law successfully alters the jet flow and improves the mixing of particles with mass and passive scalar.