Simulation Of Fluctuating Pressure Induced By Propeller Of The Wind-assisted Ship

The fluctuating pressure induced by propeller,as the main incentive to cause ship vibration,has been attracting attention since its discovery.Because the wind-assisted ship is environmentally friendly and energy-saving,our country is very concerned about it.There is a certain heeling angle and rudder angle while sailing because of its particularity.Therefore,it is very important and meaningful to predict the fluctuating pressure induced by propeller of the wind-assisted ship and discuss the influence of heeling angle and rudder angle on it.There are different methods to predict the fluctuating pressure.However,the theoretical method is complex and difficult,the cost of model test is high and the application of empirical formula is limited.In recent years,the computational fluid dynamics has gradually developed,and it can make up for the lack of other methods to a certain extent.Therefore,the CFD method is used to predict the fluctuating pressure in this paper.Firstly,the fluctuating pressure is calculated,just considering the single phase of water.The calculation result is analyzed and compared with the test result.It is found that the simulation is relatively reasonable.The feasibility of the CFD method is preliminarily verified.The propeller performance and ship resistance are also calculated in this part.Then,the VOF model is used to simulate the free surface and calculate the fluctuating pressure.The results show that compared with the consideration of the water phase only,the simulation is more accurate with the multiphase flow model and the error can be controlled in a definite scope.The reliability of the method in this paper is verified.The changes of propeller performance and ship resistance are also analyzed.Finally,three sets of working conditions were set up to discuss the influence of heeling angle and rudder angle.First,the rudder angle is zero.The fluctuating pressure is calculated at different heeling angle.The influence of heeling angle on fluctuating pressure is discussed by analyzing the results.Second,the heeling angle is zero.The fluctuating pressure is calculated at different rudder angle.The influence of rudder angle on fluctuating pressure is discussed.Third,both the heeling angle and the rudder angle are not zero.The fluctuating pressure is calculated and the comprehensive influence is discussed.In the three sets of working conditions,the influence of the heeling angle and the rudder angle on propeller performance and ship resistance is also discussed.