Numerical Study Of The Hydrodynamic Performances Of Surface Piercing Propeller

Surface piercing propeller is one kind of special propeller. It has been more widely used in high-speed boats and shallow-draft boats due to its high efficiency, less appendage resistance and reduction of blade erosion. However, little has been known about the characteristic of the flow field around this kind of propeller. The performance of surface piercing propeller was studied mainly by means of theoretical calculations and experiments. But, they all had their own limitations. The hydrodynamic numerical simulation was very rarely involved in the research for such special propeller. In this paper, CFD method was utilized on the studies of it.The hydrodynamic performances of a right-hand surface piercing propeller with five blades were investigated based on numerical simulation. The flow field was solved through Reynolds Averaged Navier-Stokes equation (RANS).The free surface was captured through the VOF method and the rotation of the propeller was handled by means of sliding mesh. The conclusions were shown as follows. In the low depth of immersion, numerical simulation could supply a good prediction of propeller performance. With the increase of the immersion, the results are accurate enough for thrust coefficient and efficiency. But there are some deviations for torque coefficient prediction. In addition, CFD method could predict the vertical force and the side force developed by the propeller. The location of the thrust was achieved accurately. It also could provide the change of flow field during water entry and exit of the blades.The numerical methods presented in this paper give instructions for the future numerical simulations. And the results are important for the investigations and the optimum designs of surface piercing propeller in the future.