Experiments on the elastoid-inertia oscillations of a rigidly rotating fluid in a cylindrical vessel

The inertial waves can occur in swirling flows under certain conditions. One of the fundamental phenomena due to the inertial waves is the 'elastoid-inertia oscillation' which is a standing-wave oscillation of a fluid in a rotating cylinder. In the experiment reported here, the elastoid-inertia oscillations of several modes are induced as resonant states by a specially designed apparatus. The patterns of the flow field and resonant frequencies are examined by means of visualization techniques. The experimental results are compared with those of the inviscid linear theory. It is found that both the frequencies and flow patterns of the actual elastoid-inertia oscillations can be well estimated by the linear theory.