VIBRATION OF A HYDROELASTIC SYSTEM CONSISTING OF A SECTOR SHELL AND VISCOUS LIQUID IN ZERO GRAVITY

Abstract

For a circular sector system consisting of an elastic shell to which an incompressible and viscous liquid layer is attached, the coupled liquid-structure frequencies are determined under zero gravity conditions. The influence of the viscosity of the liquid, the flexibility of the shell, the thickness of the liquid layer and the Ohnesorge number have been determined for freely slipping and anchored contact lines. With increasing shell flexibility the oscillation frequencies decrease and exhibit a smaller magnitude for a viscous liquid than for a frictionless liquid. In addition, we observe a phenomenon not present in a system with frictionless liquid, involving regions of only aperiodic motion. In these regions, depending mainly on viscosity (Ohnesorge number) and liquid layer thickness, the hydroelastic system cannot perform any oscillatory motion. A motion identification chart is presented showing that for large Ohnesorge number Oh≡(ρν2/σa)1/2only very thick liquid layers are able to perform oscillatory motions. Increasing the flexibility of the shell results in an increased region of aperiodic motion.