I.V. Naumov, V L. Okulov, J.N. Sorensen
Institute of Thermophysics SB RAS,
Technical University of Denmark

Experimental investigation of vortex multiplets in lid-rotated cavity flow by 3D-PIV

This paper presents results of a laboratory experiment aimed at studying the appeared multiplets in confined swirling flow driven a lid in a cylindrical cavity. Time-resolved Particle Image Velocimetry (PIV) was used to measure the flow in a cylindrical cavity with a rotating lid for Reynolds number based on cylinder radius and lid edge speed in the range 2000-4000. Proper Orthogonal Decomposition (POD) was used to detect not only instantaneous flow structures, but also the frequencies associated with the flow structures. The boundary of the transition to unsteady flow regimes, which arises as a result of the equilibrium rotation of self-organized vortex multiplets (triplet, double triplet, double doublet, and quadruplet), has been experimentally determined for aspect ratios 3,0  h  5,5.
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