The Effect of Wall Normal Actuation on a Turbulent Boundary Layer

Abstract

In this work, a series of direct numerical simulations are conducted to study the effect of wall normal spanwise homogeneous wall actuation on a turbulent boundary layer. The moving boundary is represented by a boundary data immersion technique. A parametric study was performed, varying the actuator length, the wall normal actuation amplitude and the actuation frequency. It was found that localized actuation, relying only on wall motion instead of requiring a plenum in the case of synthetic jets, generated a net momentum flux jet affecting the flow not only in the immediate vicinity of the actuator but also for a significant distance downstream. The cases with an actuator velocity of uact+=2..