Numerical prediction analysis of propeller exciting force for hull–propeller–rudder system in oblique flow

TLDR

The study aims to analyze propeller exciting forces by numerically predicting the KCS ship model for a hull–propeller–rudder system using a hybrid grid with RANS and VOF methods. Numerical hydrodynamic simulations of a bare hull at oblique states were performed and propeller bearing forces for the hull–propeller–rudder system in oblique flow were calculated using RANS and VOF. Increasing drift angle raises resistance, side force, and yaw moment, degrades propeller disk uniformity, and amplifies thrust and torque fluctuation peaks—especially at negative drift angles—while side force and bending moment fluctuations follow distinct variation patterns.

Abstract

In order to analyze the characteristics of propeller exciting force, the hybrid grid is adopted and the numerical prediction of KCS ship model is performed for hull–propeller–rudder system by Reynolds-Averaged Navier Stokes (RANS) method and volume of fluid (VOF) model. Firstly, the numerical simulation of hydrodynamics for bare hull at oblique state is carried out. The results show that with the increasing of the drift angle, the coefficients of resistance, side force and yaw moment are constantly increasing, and the bigger the drift angle, the worse the overall uniformity of propeller disk. Then, propeller bearing force for hull–propeller–rudder system in oblique flow is calculated. It is found that the propeller thrust and torque fluctuation coefficient peak in drift angle are greater than that in straight line navigation, and the negative drift angle is greater than the positive. The fluctuation peak variation law of coefficient of side force and bending moment are different due to various causes.