Research On Performance Of Propeller Cavitation And Noise

Propeller is one of the most widely used propulsors, when it’s operating, thedistribution of underwater velocity and pressure fields will change, also intenseradiation noise will be produced, which is the key objective of underwater exploration.Propeller noise affects the stealth of the ship, consequently the ship’s survivability andbattle effectiveness are affected, which is critical for the naval ships. The propellergenerally operates in a non-uniform wake feld behind the vessel. As the propellerrotates, it is subjected to unsteady force, which leads to discrete tonal noise andcavitation. So how to forecast propeller cavitation and noise with the help of software isbecomes very important.This paper aims at forecasting propeller’s hydrodynamic performance, cavitationand noise based on Propeller theory, Computational fluid dynamics, Surface panelmethod and Acoustic analogy theory with the help of Pumplinx and Actran. Theresearches include calculation of propeller steady and unsteady hydrodynamicperformance, prediction of propeller cavitation, cavitating and non-cavitating noise.Firstly, the development process of ship propellers is expounded systematically inthis paper, which summed up the theory, experimental research status and developmenttrends of the propeller’s hydrodynamic performance, cavitation performance and noiseperformance.Secondly, the propeller’s steady and unsteady hydrodynamic performance ispredicted in time-domain, where the fluid is set as ideal fluid. The prediction is down inPumplinx based on N-S equation and compared with analytical method. Finally, thedistributions of velocity and pressure fields are presented.Next, the propeller cavitation is forecasted also using Pumplinx based onpotential-based panel method. The influence factors of propeller cavitation are analyzed,such as cavitation model, calculation method, potential depth, velocity and so on.At the end, the propeller noise is forecasted using Actran based on acousticanalogy theory and fourier transform. The sound pressure level and sound powerspectral density in different positions are given. The noise attenuation characteristicwith distance changing is presented. The impacts of the different calculation steps onthe calculation results, the impact of velocity changes in flow on frequency spectrum as well as the impact of change of the cavitation number on the acoustic spectralcharacteristics related to the propeller are studied in the paper.This paper is devoted to forecast propeller cavitation and noise, which makes sensefor the design of propeller.