Instabilities in experiments with differential rotation in a split cylindrical cavity

The flow developed in a closed cylinder split in two halves that can rotate with different velocities is studied experimentally. We explore the situation analyzed numerically by Gutierrez-Castillo et al. (Gutierrez-Castillo and Lopez, 2015, 2016). Our preliminary results reveal that the coexistence of rotating internal waves is present in the experiment as it was predicted numerically. These internal waves can appear on top of the average flow, or as a new state connected through an heteroclinic orbit with the base state, producing a bistable regime. The residence times of the average flow on each one of the states is obtained, and obey a Kramer’s escape rate distribution. Other behaviors are observed, as modulations of the average flow with different combinations of the main frequencies of the experiment. • Turbulent flow instabilities with different symmetries are observed in a split cylinder • Inertial waves with a high azimuthal wavenumber appear where boundary layers collide • The residence time for each one of the observed flows obeys a Kramer’s escape rate