Vibration Characteristics of an Elastically Supported Single Circular Cylinder under Steady and Pulsating Flow Condition

抄録

The present study investigates the vortex-induced vibrations (VIV) of a long slender cylinder under steady and pulsating flow. In this study, the VIV hydro generator, one of a small energy-harvesting device, which distributes electric power to monitoring sensors, was mentioned. The developed VIV device incorporates an elastically supported cylinder (D =25 mm) with two plate springs generating piezoelectric power, and a variable stiffness controller is installed to adjust the plate spring length according to the vortex shedding frequency. In this paper, the vibration characteristics of the elastically supported cylinder are evaluated under the laminar and the pulsating flow produced by an agricultural irrigation channel flow and a seawater exchange channel flow driven by nearshore waves. As the result, the VIV device extracts a 30-mm vibration amplitude (peak-to-peak) in steady flow (Re = 7,470–14,940), and unclear signs of a lock-in phenomenon were observed. In pulsating flow field with 0.17–0.50 Hz, the test cylinder vibrates with the lock-in frequency, as well as with the steady flow.This information is significant for setting the various parameters on VIV hydro generators.