System identification and control of a turbulent boundary layer

An experimental investigation is made into the active control of the near-wall region of a turbulent boundary layer using a linear feed-forward control algorithm. A wall-based detection scheme is described which effectively detects coherent structures and predicts downstream flow behavior. A simple demonstration, using three wall-based sensors and a single actuator, achieves a maximum of 31% reduction in $u_{\mathrm{rms}}$ and 17% reduction in $p_{\mathrm{rms}}.$