Hydroelastic Vibrations of Flat Plates Related to Trailing Edge Geometry

Abstract

Vortex-induced vibrations of thin flat plates are studied as a function of trailing edge geometry. In an effort to extend the analysis to a more comprehensive treatment than that provided by the common vortex model, the vibrations are considered as hydroelastic phenomena. An equation of motion is formulated. From a qualitative analysis of this nonlinear equation some expected features of its solution are set forth. A detailed experimental determination is made of the amplitude spectra of various thin plates mounted at zero mean angle of incidence in the test section of a water tunnel and suspended by a torsion spring through their leading edge. The effects of trailing edge geometry and elastic properties of plate support are explored. Data analysis gives interesting confirmation of the formulated equation of motion. The vibration is shown to become self-excited and the degree of two dimensionality of the wake is deduced to be determinative in regard to the severity of the vibration.