Experimental analysis on the risk of vortex ventilation and the free surface ventilation of marine propellers

Experimental data based on several different model tests shows the boundary between the vortex forming, non-vortex forming and free surface ventilation flow regimes. For comparison the following parameters, which determined the intensity of the hydrodynamic interaction between the propeller and free surface have been used: propeller load coefficient cT, tip clearance ratio c/D, propeller submergence ratio h/R, ambient velocity Vi and flow cavitation/ventilation number σcav/σvent.