SummaryThe present paper deals with the effect of the geometric characteristics on the propeller hydrodynamic performances. Several propeller configurations are created by changing number of blades, expanded area and pitch ratios. The Reynolds-Averaged Navier-Stokes (RANS) equations are solved using the commercial code FLUENT 6.3.26. The standard − and the − models are used for the steady uniform and the transient non-uniform ship wake. Overlapping propellers arise from high expanded area involve that the computational domain should be created with several multi-blocks. Thrust, torque and efficiency coefficients of the generated propellers are compared with available experimental data. The computational results reveal that both standard − and − models guarantee acceptable level of accuracy in open water condition and unsteady flow predictions. This parametric study has also allowed achieving optimal shape factors ensuring best hydrodynamic performances.

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The appropriate choice of a marine engine identified by using self-propulsion model tests is compulsory, in particular with respect to the improvement of vessel performances. Numerical simulations or experimental methods provide insight into the problem of flow, where fixed pitch propellers or controllable pitch propellers are preferred. While calculation methods are time consuming and computationally demanding for both propeller types, hydrodynamic performance assessment has more workload in controllable pitch propellers. This paper aims to describe and demonstrate the practicability and effectiveness of the self-propulsion estimation (SPE) method in understanding the effect of propeller pitch on ship propulsion. Technically, the hydrostatic and geometric characteristics of the vessel and open-water propeller performances are the focal aspects that affect the self-propulsion parameters estimated by the SPE method. The input coefficients for SPE have been identified using a code that generates propeller open-water performance curves. The propellers utilized to study pitch variations have been based on the Wageningen B-series propeller database. The method was first validated on the full size Seiun Maru ship whose sea trial tests are available in literature. After extensive calculations for full size KCS and DTC at service speeds, the study focused on the effect of the Froude number on propulsion parameters. These calculations have demonstrated that greater propeller pitch does not improve propulsion efficiency, and that maximum propeller efficiency changes with a ship's forward speed.

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The objective of the current paper is to study the flow around Seiun Maru Highly Skewed (HSP) marine propeller by assessment of blade forces and moments under non-cavitating case. The calculations are performed in open water (steady case) and non-uniform ship wake (Unsteady case). The governing equations based on Reynolds Averaged Navier-Stokes Equation (RANSE) are solved using Finite Volume Method. Ansys Fluent 14.0 is used to implement the simulation. For the steady case, Moving Reference Frame (MRF) is selected while sliding mesh technique is adopted for the unsteady case. Calculated open water performances in terms of thrust and torque coefficients fit very well with experimental data for a wide range of advance ratio. In the unsteady calculations, axial velocities, deduced from the nominal wake, are introduced in the Ansys fluent code. To locate suitably the non-uniform wake in the propeller front plane, three positions of inlet wake have been taken into account to determine their effects on the accuracy of the results. Obtained results show that computed performances are improved compared to panel method when the inlet is close to the propeller.