Slip flows of Newtonian and viscoelastic fluids in a 4:1 contraction

Increasing the slip coefficient leads to the formation of two vortices, a corner and a lip vortex. The lip vortex grows with increasing slip until it absorbs the corner vortex, creating a single large vortex that continues to increase in size and intensity. In the range De = 3-5 no lip vortex was formed. The flow is characterized in detail for De=1 as function of the slip coefficient, while for the remaining De only the main features are shown for specific values of the slip coefficient.