Numerical Assessment of Twin-Propeller Performances

The paper describes a methodology for assessing the hydrodynamic performances of a four blade fixed-pitch propeller working in open water. Both single propeller and twin-propeller arrangements are studied. The numerical solver, which is a part of the Numeca FineTM-Marine package is based on the finite volume method. Closure to turbulence is based on the detached eddy simulation (DES). A double sliding grid technique is used to treat the contra-rotational flow around the propellers. A grid convergence test is carried out to verify the robustness of the numerical treatment. Comparisons with the experimental data for the single propeller are performed twice to validate the ISIS-CFD viscous flow solver for both starboard and portside propellers. Discussions based on the numerical solutions are provided aimed at clarifying the particular issues of the hydrodynamic interference between the two propellers. Finally, a series of remarks are concluding the findings of the present work.