Experimental investigation of a swirling flow in a cubic container

A flow induced by a rotating disk mounted at the top of a cubic container totally filled with a liquid is studied experimentally. The flow pattern is visualized for Reynolds numbers in the interval 1500–6000, and the velocity variation along the axis of the container, which coincides with the axis of revolution of the disk, is observed by means of Doppler laser anemometry (DLA). As Re grows, the velocity axial component starts fluctuating because of the vortex core precession. The breakdown of the vortex helical structure becomes pronounced at Re>4000 without the formation of the return flow region (vortex breakdown bubble) at the axis. With the Reynolds number and the container height-to-disk radius ratio being the same, the axial flow patterns in standard cylindrical [1] and cubic containers differ radically. In the latter vessel at low Re, the steady flow regime and axisymmetric bubble breakdown of the vortex structure near the axis are absent.