ABSTRACT
In actual navigation, due to high-speed navigation, the propellers of high-speed boats often rise to the sea surface, and there is a special working condition in which the propeller is incompletely submerged. The calculation and study of the propeller excitation in this working condition is the key to optimizing the whirling vibration of the shafting. In order to obtain the calculation method of the excitation in this working condition, the theoretical calculation method of the propeller excitation is given based on the hydrodynamics theory of water entry. After appropriate corrections are made using the fluid simulation software Ansys Fluent, the numerical simulation of the propeller in the incompletely submerged state is carried out. The research results show that the numerical simulation model predicts the pulsation characteristics of the six components of the semi-submerged propeller (propeller shaft direction, vertical and lateral direction) that affect the whirling vibration of the ship’s shafting. The working characteristics of the semi-submerged propeller cause greater the pulsation changes of the vertical excitation force and the lateral excitation force lead to aggravation of the whirling vibration effect on the ship shafting. And the positioning method for the position of the semi-submerged propeller blade is obtained.
