Abstract
In the present simultaneous spectral and flow-visualization measurements, the disturbance is visible using a suspension of small aluminium or Kalliroscope polymeric flakes that align with the flow, and the intensity of laser or light-emitting-diode light scattered by the flakes is simultaneously measured. The disturbance structure is clarified and the fundamental frequency of the velocity fluctuation is identified by comparing the results of the visual observation and the spectral analysis of the scattered-light intensity.
The present method using simultaneous spectral and flow-visualization measurements is applied to analyse various disturbance appearing in the spherical Couette flow between rotating spheres and the radial flow between two parallel disks with an axial inflow.
