Axisymmetric inertial oscillations of a fluid in a cylindrical cavity during spin-up from rest

Abstract

Abstract The dependence of inertial oscillation frequency on time since a cylindrical container began rotating from rest is established experimentally for several axially symmetric modes of oscillation. The oscillations were excited by including a sinusoidal perturbation in the rotation speed of the container which served to establish an exchange of fluid between the viscous boundary layers and the interior. The interior is set into oscillation by the boundary layer flow and the resulting axial pressure differences are used to establish the amplitude of the inertial oscillation. The best agreement between our experiments and the theoretical work by Lynn (1973) on the time dependence of inertial oscillation frequency occurs for the lowest frequency modes. From a limited study on amplitude of the inertial oscillations it appears that the growth rate of these disturbance is such that e −1 of the ultimate amplitude is achieved after one and a hall spin-up times from the time that the container is switched on....