An Experimental Study on High-speed Flow Induced Vibrations of Thin Plate

Abstract

Vibration characteristics of a thin plate in water flow at high speeds of 1~9 m/s are presented. The purpose of experimental study was to observe occurrence pattern of flow induced vibration with the flow speeds, if applicable, and to find some relationships between the frequencies of vibrations and the flow speeds. The plate, a rectangle of size 48mm x 18mm x 0.267mm, was subjected to clamped-free-clamped-free boundary conditions and its vibration velocities were measured at several points using a non-contact laser vibration transducer. The measured results show that the amplitude of vibration increases suddenly and then settles down in several regions of the flow velocity and frequencies of the vibration at such region are proportional to the flow velocity. These observations are thought to be an extension of observations on the vortex induced vibration of a single degree of freedom system in the fluid flow. By confirming that the frequencies of significant vibrations coincide with those of natural frequencies of the plate, it is expected to be able to estimate addition of mass for thin rectangular plates in the high-speed flows.