LES of cavitation inception in a shear layer*

Cavitation inception in a shear layer is numerically investigated using a backward-facing step configuration, with an inflow turbulent boundary-layer of Reτ=1500 and at two values of cavitation number. PDFs of pressure and vapor volume fraction show that inception has a higher probability of being observed in the axial position of 0.4 < x/Lr < 0.8, where Lr is the reattachment length, agreeing well with experimental data. An analysis of the incipient topological structures is performed and it is revealed that inception is more likely to occur at the cores of the elongated vortical structures. These structures are found to have a rotation rate 4x higher than their straining rate.