Effect of non-axisymmetric inertial waves on the steady fluid circulation in a rotating cylinder

Non-axisymmetric inertial waves in a rotating cylindrical cavity are studied experimentally. To maintain the wave motion, the cavity rotation rate is periodically changed according to the harmonic law (libration). Three different regimes have been found: non-resonant traveling wave, inertial mode resonance, and resonant traveling wave. In the first case, the pulsating flow represents a set of individual wave beams emittedfrom the cavity corners. The reflection of beams from the cavity sidewall induces steady circulation in the dynamic boundary layer, where the direction of the circulation is deter-mined by the direction of wave front propagation. The second regime resembles standing waves in the axial section of the cavity. The fluid oscillations within the cavity also produce a steady flow with a structure specified by the axial wavenumber of the mode. Finally, the third regime is characterized by alternate excitation of two axisymmetric modes or one non-axisymmetric mode with an axisymmetric mode. In this case, the propagation of the wave front in the form of a traveling wave is a result of the interaction of two modes with different wave numbers. At the same time, the steady flow structure becomes more complex: the waves converging (diverging) to each other induce a system of concordantly rotating steady vortices near the sidewall.