Viscoelastic jet instabilities studied by direct numerical simulations

The evolution of inertio-elastic shear-layer and jet-column instabilities of submerged jets of viscoelastic polymer solutions is studied by direct numerical simulation. At high Reynolds numbers, viscoelasticity has a destabilizing effect in the linear region of perturbation growth, but stabilizes the jet perturbations at the nonlinear regime. Two competing instability mechanisms are identified and analyzed in order to explain the observed results for the different regimes.