Conventional Propulsion System
By BEM Application

In the analysis of the hydrodynamical action of the marine propeller behind a ship an increasing amount of attention is being given to the effects of the non-uniform inflow. Presence of the hull in front of the Popeller Rudder System (PRS) causes substantial changes in distribution of inflow to the propeller to be three dimensional non-uniform flow. For hydrodynamic characteristics of propeller, axial velocity is interest while radial and tangential components are important on cavitation and vibration problems. This is practical importance to design the hull structure to equalize the wake distributions. The present inflow considered the estimated non-uniform flow subject to the PRS to investigate the hydrodynamic performance.
Since a theoretical treatment of the simplified propeller theory was presented by R. Yamazaki, then employed numerically by many researchers, for example Moriyama, Tamashima and Matsui mainly in uniform condition. The present study involved both experimatal data and numerical solutions in non-uniform condition.
The simplified propeller theory is applied to the propeller as a disc with infintly bladed and obtaind the vortex, potential distribution and flow field around the propeller. From the kinematic boundary condition of the propeller, the vortex of propeler is calculted via an iterative procedure to converge the free vortex pitch. On the other hand, the potential surface panel method which is composed of the combination of dipoles and sources distribution on the rudder and also, dipole distribution on the trailing vortex wake to represent the potential flow around the rudder. However, an interactive iteration procedure is required to predict interaction between the propeller and rudder by the induced velocity due to the other. Special emphasis is considered to determine the velocity components behind the propeller.
  • Panel Arrangement for Conventional Propulsion System
  • Panel Arrangement for Podded Propulsion System

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