VISCOUS HYDROELASTIC VIBRATIONS IN A CYLINDRICAL CONTAINER WITH AN ELASTIC BOTTOM

The coupled motion of a viscous liquid in a cylindrical container with an elastic bottom is treated. The liquid exhibits a free surface with surface tension. The hydroelastic frequencies and decay magnitudes are determined for the lower angular- and radial modes, for which the influences of the various parameters are investigated. A new phenomenon was detected, showing that for low liquid height ratio an aperiodic range appears, in which the viscous liquid is not able to oscillate. This range decreases with growing membrane tension and increasing mode number. In addition, it was found that higher liquid modes experience larger damping and disappear from the motion as time goes on.