In this talk, the use of active control to change the dynamics of idealized fluid-structure interaction (FSI) systems will be introduced. Here the term “active control” means that the control is realized by injecting a small amount of energy into existing FSI systems. Compared to its counterpart, i.e., passive control, active control is adaptive and on-demand, and hence has a much wider operating range.
First, the control of wakes and vortex-induced vibrations of a circular cylinder using synthetic jets (SJs) will be introduced. As an associated phenomenon, lock-on of vortex shedding to a pair of SJs will be discussed.
Second, enhancement of flapping-foil aerodynamics using various active control methods, including SJs, leading-edge perturbations and adjustable flexibility, will be presented.
Last, the adoption of machine-learning methods on active closed-loop control of a cylinder flow system will be demonstrated.