Flow Control on a Plunging Circular Cylinder

Flow control on a periodic-oscillating body is a critical issue due to its applications in a wide range of engineering systems (such as rotating wind turbines and plunging airfoil of an airplane under turbulence). The major researches regarding flow controls focus on the stationary boundary. Therefore, we aimed to tackle this issue by proposing control methods that target at attenuating the additional fluctuation induced by the oscillating motion of the boundary. Moreover, the control result on the periodic case is expected to shed light on the even more complex dynamic with free-moving boundaries. A plunging cylinder is chosen as a demonstrative case. Both open-loop and closed-loop control schemes were established based on Resolvent analysis and verified by DNS of Immersed Boundary Projection Method.

The optimal cases of open-loop flow control on a plunging cylinder.