System Identification of Fluid Force Model Applying to an Elastically Supported Circular Cylinder Undergoing Vortex-Induced Vibration

Abstract

Flow induced vibration is well known phenomena in the mechanical systems. When vortex shedding frequency gets close to natural frequencies of structures, the both frequencies are synchronized and the amplitude of vibration of the structure becomes larger and larger. This phenomena is an obstacle for improving the performance of the mechanical systems such as Hard Disk Drives. This study proposes the system identification of the vibration control oriented fluid force model by using sensor information of only displacement of the structure. In this study, fluid force model, on which the vibrations of the structures are fed back to the fluid forces and the amplitude of the excitation force of the fluid becomes larger and larger, is assumed for the identification. The identified fluid force model by proposed method is confirmed by experiments in which the feedforward control of the vibrations is applied to the flow-structure coupled vibration system.