Closed-loop control of fluid-structure interactions on a flexibly supported cylinder

摘要

This work proposes a closed-loop control of vortex-induced vibrations on a flexibly supported square cylinder. One side of the cylinder was perturbed using actuators, which were controlled by a proportional-integral-derivative controller with its feedback signal provided by a hot wire placed in the near wake. The particle image velocimetry, hot wire and laser vibrometer measurements indicate that the perturbation has completely modified the fluid-structure interaction, drastically impairing the resonance between vortex shedding and vortex-induced structural vibration. Compared with an open-loop control, the closed-loop control has two advantages. Firstly, the perturbation amplitude required to suppress vortex shedding/structural vibration is reduced by about 70%. Secondly, the closed-loop control always suppresses vortex shedding/structural vibration, while an open loop may, or may not, depending on the relationship between the vortex shedding and perturbation frequencies.