Shocklet formation in vortex reconnection*

We study the mechanisms of shocklet formation in a transonic viscous vortex reconnection. Shocklets emerge due to spatio-temporal variation of the pressure and induced velocity fields as the vortex tubes approach. The shocklets, if sufficiently strong, can result in early circulation transfer and modify the reconnection dynamics. Due to the strong dilation component, shocklets play an inevitable role in the reconnection noise. A decomposition of the Lighthill's source term is provided and the evolution of all dominant terms through shocklets are investigated. The current study provides a detailed analysis of the shocklets which are estimated to be critical features of the reconnection at high $Re$.