Active control of very-large-scale motions using wall deformation

I will discuss the activities of my research group on the experimental development and understanding of the effects of active surface deformation on a turbulent boundary layer, with particular emphasis on its impact on very large-scale motions (VLSMs). My talk will cover the development of an actuator driven by a voice coil for on-demand surface deformation, along with a real-time particle image velocimetry (PIV) system for flow sensing. Our preliminary experiments have evaluated the ability of active surface deformation to control ejections and sweeps in a simple periodic flow and have characterized the effects of periodic actuation in both laminar and turbulent boundary layers. The insights gained from these experiments have been used to implement a feed-forward system to control VLSMs in a turbulent boundary layer. The results demonstrate how active surface deformation can influence the strength of VLSMs and provide guidelines for the future development of active deformable surfaces in practical applications.