Wideband spectrum noise forecasting method in cavitation inception state of combined propeller

Abstract

The invention discloses a wideband spectrum noise forecasting method in a cavitation inception state of a combined propeller. A target combined propeller geometric model, a fluid mesh model and a fluid dynamics analysis model are built, steady-state cavitation-free turbulence solution, steady-state cavitation turbulence solution and transient state cavitation turbulence solution are carried out sequentially until cavitation multi-phase turbulence of each time step after iteration time steps are reduced is solved, and cavitation noise is worked out along with a built acoustic boundary element mesh. A verification step adaptive to each calculation step is arranged after the corresponding calculation step, and the technical scheme of three criterions for judging the cavitation inception state is firstly created. The wideband spectrum noise forecasting method in the cavitation inception state of the combined propeller can guarantee that the forecasting error of the spectrum level in the position of one third octave center frequency at the frequency band above 800Hz of a rotary paddle and a pump is less than 3db, and the forecasting error of the total sound level is less than 4db, can be used for forecasting the cavitation inception navigational speed of a torpedo or a submarine, and directly serves the scheme design of a novel high-speed and low-noise torpedo and submarine.

Description

technical field [0001] The invention relates to a prediction method of propeller cavitation radiation noise, in particular to a prediction method of wide-band spectrum noise of a combined propeller represented by a contra-rotating propeller and a pump-jet propeller in a cavitation incipient state. Background technique [0002] The counter-rotating propeller (referred to as the counter-rotating propeller) is the main propeller of the existing electrodynamic torpedo, and consists of a coaxial, counter-rotating front propeller (abbreviated as the front propeller) and a rear propeller (abbreviated as the rear propeller). Usually, the diameter of the rear propeller is smaller than that of the front propeller, and the number of blades is less in order to avoid the tip vortex shedding of the front propeller and interact with the leading edge of the blade to radiate sound. The pump jet propeller (abbreviated as the pump jet) is the main propeller for existing thermodynamic torpedoes...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the noise prediction problem of the combined thruster in the cavitation incipient state, the present invention provides a credible numerical prediction method for wide-band spectrum noise in the cavitation incipient state of the combined propeller, which can Accurately determine the initial cavitation speed of torpedoes or submarines

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