Breakdown regime of a shielded vortex interacting with a standing normal shock: a numerical study

Numerical simulation results of a convecting shielded vortex interacting with a normal shock using a compact scheme in the convecting upwind and split pressure framework are presented. We explore the parameter space spanned by vortex Mach number and incident Mach number to look for combinations of the parameters which lead to vortex breakdown. The incident and vortex Mach numbers covered are on the higher side, where relatively less information is available. It is well known that for a weak shock, the vortex retains its original shape and for stronger shocks it breaks down. In-between these two extremes, there is a region where the vortex neither retains its original shape nor does it break into small pieces. We determine the vortex breakdown and transition regions that have not so far been reported in shock–vortex interaction studies. A number of cases have been studied, and a vortex breakdown criterion for the cases considered is proposed.