Numerical study of the effect of the free surface on the hydrodynamic characteristics of the model and full-scale marine propeller

The article examines the effect of the free surface on the hydrodynamic characteristics of the propeller by numerical simulation in Logos software package. The numerical approach is based on a three-dimensional system of Reynolds averaged Navier-Stokes equations, which is closed by the SST Menter turbulence model together with the laminar-turbulent transition model $\gamma - {{\mathop{\rm Re}\nolimits} _\theta }$. The Volume of Fluid method is used to account for the free surface. A rotating propeller is simulated by a moving computational mesh and flow interpolation through a mesh interface. The method validation results are given, they were obtained on the problem of finding the open water performance of model-scale propeller KP505. The results of numerical simulation of a model and full-scale operating propeller with different depth of immersion are presented. It has been shown that the small immersion depth of the propeller most strongly affects the propeller performance at the small advance coefficient due to the occurrence of aeration. The obtained thrust and efficiency of the full-scale propeller are higher than the model coefficients, which is also observed for propellers operating under open water conditions without a free surface.