Abstracts:

 

A swirling water jet is designed and constructed with easily controllable azimuthal and axial velocities for the study of vortex breakdown phenomena. Both visualization and velocimetry measurements are carried out to study the instabilities caused by the swirling motion of the jet. It is found that the order parameter (For instance, the thickness of the mixing layer in the visualization experiment) undergoes a supercritical bifurcation when the swirling number reaches a threshold. This transition is verified to be responsible for the occurrence of vortex breakdown.

 

For more information see: Paper in Latex