A numerical study of the shear-less turbulent/non-turbulent interface

A DNS simulation of an interface between a decaying turbulent flow without mean shear and a quiescent non-turbulent region is presented here. The analysis of the instantaneous fields highlight a complex multi-scale behaviour at the turbulent/non-turbulent interface. According to previous results in the literature, by analysing the enstrophy budgets it is possible to observe that enstrophy propagate from the turbulent region mainly by inviscid process while viscous diffusion is relevant only at the interface