A Method for Establishing Wave-Vibration Nonlinear Sound Field in Bubble Water Medium

Abstract

The invention relates to a method for establishing a wave-vibration nonlinear sound field in a bubble-containing water medium, which includes establishing a "wave-bubble volume third-order vibration" equation; setting initial conditions and boundary conditions; determining a time length T t and the spatial distance T l , set the step size to divide the grid; rewrite the differential term to the differential form; obtain the differential equation system by coupling the "wave-bubble volume third-order vibration" equation to the sound source term; set the initial values ​​of the sound pressure and bubble volume change; calculation time node n t After bubble volume change value and sound pressure value n t add 1; when n t ≤N t , repeat the previous step, and calculate to the last point N in the time domain t , when n t =N t , reset n t = 3; use the initial parameters and the last node N on the computational space domain s The sound pressure value on n t add 1; when n t ≤N t , repeat the previous step, and calculate to the last point N in the time domain t . The invention performs coupling through the sound pressure excitation term, performs numerical coupling calculation on the wave-vibration nonlinear equation, and simultaneously obtains the nonlinear sound field characteristics and the bubble nonlinear dynamic characteristics in the bubble-containing water medium.

Description

technical field [0001] The invention relates to a method for establishing a nonlinear sound field, in particular to a method for establishing a wave-vibration nonlinear sound field in a bubble-containing water medium. Background technique [0002] Due to the disturbance of waves and wind, there are a large number of tiny bubbles on the ocean surface to form a bubble water medium. These bubbles are very stable and have a long existence period; when the surface ship is sailing, the broken bow and tail waves, propeller cavitation, etc. The air is brought into the sea water to form a bubble-containing water medium, which leads to a significant change in some of the acoustic properties of the medium, which affects the propagation of sound waves. In recent years, with the wide application of underwater large-amplitude acoustic waves, some nonlinear acoustic properties of bubble-containing water media have attracted more and more attention. In fact, the bubbling water medium itsel...

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Problems solved by technology

[0003] Van Wijingaarden first proposed the acoustic wave equation of the bubble-containing medium based on the mixed medium; Commander and Prosperitti further developed the mixed-medium theory of the bubble-containing medium, and discussed the propagation of linear acoustic waves in the bubble-containing water medium (1Commander K W ,Prosperetti A.Linear pressure waves in bubbly liquids: Comparison between theory and experiments[J].Journal of the Acoustical Society of America,1998,85(21):9383-9391.), but for the influence of nonlinear vibration of bubbles on the acoustic field It was not discussed; Zabolotskaya based on a single bubble vibration equation—Rayleigh-Plesset equation, rewritten the change of bubble radius with time as the change of bubble volume with time, and studied the dynamic characteristics of bubbles (2Zabolotskaya E A. Emission of harmonic and combination-frequency waves by air bubbles[J].Sov.phys.acoust,1973,18.); the above theories did not consider the interaction between the sound field and the nonlinear vibration of bubbles in the water medium containing bubbles

Christian Vanhulle first proposed the idea that the wave equation and the bubble vibration equation can be coupled to calculate, and then solve the sound field characteristics in the bubbly water medium and the bubble vibration characteristics (3Nolinear ultrasonic propagation in bubbly liquids: A numerical model), but for There are few studies on nonlinear sound field characteristics, and the bubble volume vibration model in this paper only considers the second-order nonlinear effect, so it is impossible to analyze the change of sound field characteristics caused by higher-order bubble nonlinear vibration

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