  Closed-loop control of turbulent flows is a challenging problem with
important practical and fundamental implications. We perform closed-loop
control of forced, turbulent jets based on a wave-cancellation strategy. The
study is motivated by the success of recent studies in applying wave
cancellation to control instability waves in transitional boundary layers and
free-shear flows. Using a control law obtained through a system-identification
technique, we successfully implement wave-cancellation-based, closed-loop
control, achieving order-of-magnitude attenuations of velocity fluctuations.
Control is shown to reduce fluctuation levels over an extensive streamwise
range.
