Large Eddy Simulations of a Confined Tip-Leakage Cavitating Flow with Special Emphasis on Vortex Dynamics

In current paper, Large Eddy Simulations are conducted to investigate the tip-leakage cavitating flow around a NACA0009 hydrofoil with a gap. The numerical result is compared with experimental data and a reasonable agreement is obtained. The vortex structures in the tip-leakage cavitating flow are well reproduced. Three types of vortex structures in tip-leakage cavitating flow are observed near the gap, the tip-leakage vortex, tip-separation vortex and induced vortexes. Compared with the tip-separation and induced vortexes, the tip-leakage vortex is much stronger and impacts significantly the development of the formers. The simplified vorticity transport equation suggests that the dilation term dominates in the whole process of vortex development, while the stretching term mainly concentrates near the end-wall of foil. The baroclinic torque is the major source of the vorticity production during the collapse of cavitation. Our work is helpful to understand the interactions between cavitation and vortexes in a tip-leakage cavitating flow.