Modifications on the Reattachment Region of a Turbulent Step Flow Using a Dielectric Barrier Discharge Actuator

This paper seeks to find an optimal actuation for controlling the reattachment region found downstream of a backward-facing step. The configuration has a 30-mm-height step. The external velocity is fixed at 15 m/s, based on that, the Reynolds number corresponds to 3 x 10(4). The control is performed via a single dielectric barrier discharge. Several actuation locations along the step model are tested and the best result regarding the modification of the mean reattachment point is observed with the actuator located at the hinge of the step. In terms of unsteady actuation, an optimal frequency is also observed for this position. For these optimal conditions, the paper introduces a brief analysis about the time-dependent modifications of the oscillations around the reattachment region.