Simulation Of Fluctuating Pressure Induced By Propeller Based On Numerical Method

The vibration problem of the ship has always been a concern, vibration will bring a series of adverse effects, even destroy the ship hull structure. According to the statistics, about 70% of the ship hull vibration is caused by propeller, the propeller induced fluctuating pressure has been the object of attention over years.The traditional theoretical calculation method on fluctuating pressure is too complicated; the cost of model test is too high; empirical formula method has its limitations. Computational fluid dynamics (CFD) as a new discipline has opened up a new path in the calculation on flow field simulation. With the computer performance developing and the continuous improving theories, CFD gradually revealed advantages. This article will use the CFD method to simulate a ship’s flow field, and extract the propeller induced fluctuating pressure.Firstly, we numerical simulate the propeller performance in open water to prove the feasibility of the CFD method. Simulations are adopted each in the standard k-ε model, RNG k-ε and Reynolds stress turbulence model to be compared. Compare the results with the open water propeller atlas, obtained the most suitable turbulence model, and draw the propeller open water performance curves. The simulation proves the feasibility and reliability of the CFD numerical method. The surface pressure distribution and flow of the propeller wake embodies the advantages that numerical simulation can obtain various kinds of information of the whole flow field.Then, numerical simulate the ship flow field with the influence of propeller. According to the flow simulation, information about hydrodynamic performance of the propeller can be extracted from the monitoring points. Thus reorganizes the fluctuation curves of propeller induced pressure fluctuation, and analyze the frequency components by using the Fast Fourier Transformation(FFT).Finally, numerical simulate the ship stern flow field with both the propeller and rudder. Get the fluctuating pressure value of monitoring points and discuss the effects of rudder on the fluctuating pressure.