Frequency response of a liquid sloshing in a rotating, laterally oscillating, cylindrical vessel

We have investigated the free-surface fluctuations of liquid in a rotating, laterally oscillating, cylindrical vessel. In the experiments, we changed independently both the lateral forcing frequency f and the rotation frequency of the cylinder. We measured the time-dependent fluid-dynamic pressure instead of the free surface fluctuations. From an FFT analysis of the dynamic pressure, we obtained two significant frequencies: f-and f +. They are associated, respectively, with waves that rotate in the same direction, and in the opposite direction, relative to the rotation of the vessel. We also examined these results using linearized wave theory.