Experimental observation of chaos-chaos intermittency types in spherical Couette flow

Flows between concentric, counter rotating spherical boundaries are under investigation in the gap with size equal to inner sphere radius. Outer sphere rotational rate is fixed, while inner sphere rotational rate has time periodic variations. The amplitudes and frequencies of these variations are small relative to both spheres averaged rotational rates. With amplitude increase transition from initial periodical flow to chaos is occurred. To determine state of the flow time series of azimuthal velocity, taken with laser Doppler anemometry, were used. We demonstrate appearance of flow states in the form of chaos-chaos and cycle-chaos-chaos intermittency. A procedure is considered which allow quantitatively confirm distinct properties of different patterns of time alternating flow state with intermittency.