Turbulence Receptivity of Longitudinal Vortex-Dominated Flows

The transient effect of turbulence forcing on an isolated vortex has been investigated by means of Large Eddy simulation. A dynamicmixed model is used to relate resolved and subgrid scale fluctuations in an incompressible CFD code. The initial condition is an Oseen vortex developing in a periodic box and subsequently forced by a superimposed turbulence. Turbulence is imposed in three different situations, separately outside or inside the initial vortex core and in the whole computational domain. The instantaneous flow field is observed for an outside forcing and it exhibits a wandering motion of the vortex as a whole. The velocity fluctuations grow near the vortex axis while it decreases for an inside forcing. The whole domain forcing is close to the external forcing, implying that most of the turbulence interaction is induced by the outer zone. An analytical investigation of the wandering effect shows that the near-axis fluctuations are mainly produced by this effect.