The paper investigates the unstable behavior of a precessing vortex core in a diffuser
behind a rotating swirler. The studies were carried out by experimental methods using a
hydrodynamic stand, and by numerical simulation of turbulent flow in the stand in the various
flow swirl modes. Both experimental and calculation studies show nonperiodic reconnection
of the vortex core and the formation of vortex rings. This instability is observed within a
narrow range of the swirl parameter between a weakly swirled flow without vortex …