Vortex-Induced Vibration of an Elastically-Supported Cylinder Considering Random Flow Effects

摘要

This paper investigates the vortex-induced vibration of a circular cylinder supported by flexible cantilever beams under a uniform air flow. To improve the vortex-induced vibration model, the chaotic phenomena of the vortex are modeled as a random component of the fluid force. Next, the vibration properties of a cylinder supported by a pair of elastic cantilever beams are investigated in wind-tunnel experiments over a wide range of flow speeds. The hysteresis property of the vortex-induced vibration is experimentally investigated under two conditions; the "increase-direction" condition, in which the flow speed is increased, and the "decrease-direction" condition, in which the flow speed is decreased. The time-historical responses of the vortex-induced vibration are measured and subjected to time-frequency analysis revealing the characteristics of the nonlinear coupled vibrations between the fluid and structure. The wake oscillator models with acceleration coupling and random components are evaluated in numerical simulations. The proposed models with random components more closely reproduce the experimental results than the ordinal model.