Numerical Simulation On Vortex Shedding Of Propeller

The vibration and noise of propeller, particularly, the abnormal noise-singing voice caused by vortex-induced resonance, is one of the three major noise sources of the ship The noise of the ship will affect the work and rest of the crew; for the warships, submarines, acoustic-homing torpedoes and other weapons whose main feature is concealment, the noise of the equipments can have a negative impact on the concealment of the weapons, expose themselves to enemies, and lead to enemy attack. Therefore, the study of vortex-induced resonance of propeller is of great significance.So far there are many sorts of method have been developed in the field of Fluid-structure interaction analysis of propeller, such as Discrete vortex method, wake oscillator method, experimental method and the finite element simulation method. And the finite element simulation methods one of the most effective and most suitable for the particular situation.This paper studied on vortex shedding of propeller by numerical simulation,based on LS-DYNA software and ALE method. In order to verify the reasonableness of numerical simulation methods, this paper researched on the vortex-induced resonance of cylinder in uniform flow,the results of numerical simulation are consistent with results by related formula.This paper researched on the vortex of one-bladed MAU4-55 propeller and four-bladed MAU4-55 propeller that are in uniform flow and with different Rotation speeds by building the Finite element model of the coupling action between the propeller and fluid; In the finite element model, the hub of one-bladed MAU4-55 propeller is set rigid material, the blade is set elastic material, the hub and two blades of the four-bladed MAU4-55 propeller is set rigid material,the other blades is set elastic material,choose the elastic blade and points of the elastic blade as research object. According to the research, the y-stress of blade is proportional to the rotation speed of blade, the vortex-induced force has a great impact on z-stress of blade and the numerical simulation calculation result of one-bladed propeller and four-bladed propeller under same condition is close, In the case of less precision requirement, the vortex distribution of multi-blades model can be replaced by one blade model,thus greatly reducing the workload and the numerical simulation time.