Numerical Simulation Research For Propeller Singing

In the field of marine engineering, the noise of propeller vibration is one of the major noises of the ship, especially the noise caused by resonance-singing. Propeller singing is the phenomenon of nonlinear acoustic, which is the resonance of the blade caused by the excitation of turbulence. In other words, when the frequency of vortex shedding and the natural frequency of blade are close, it will inspire the resonance, which is the propeller singing. When propeller singing occurred to the ship, it will lead to the strong vibration and boring noise. And the vibration of blade may cause fatigue damage. In addition, propeller singing is the main component of low frequency (1-100Hz) noise. It will impact the concealment and combat of submarine. So the research for propeller singing is quite significant.At present, the research of numerical simulation on propeller singing is little involved. If under the existing conditions, we can establish a relative reasonable model. And the frequency of vortex shedding is calculated in different flow speed and rotational speed, which is relied on the computer. Then the result can be compared with the natural frequency of the propeller. If we finish this, we can predict propeller singing in the design stage of the propeller. However, due to the current power of computer, there are still difficulties.Therefore, this paper will do some work from the perspective of numerical simulation on propeller singing. First, I will study on vortex shedding of the profile of cylinder and blade, based on Arbitrary Lagrangian-Eulerian method (ALE). And the results of numerical simulation will be compared with that of the empirical formula. Then, according to the method above, I will research on vortex shedding of three-dimensional cylinder and one blade of propeller. Before the structure, it will be applied to flow, which is converted by the number of revolutions of host. Finally, the analysis of frequency response will also be carried out.