Abstract

TEJEDOR SASTRE, María Teresa  and  VANHILLE, Christian. An analysis of nonlinear ultrasonic waves in bubbly liquids by a numerical model. Rev. Mat [online]. 2023, vol.30, n.1, pp.121-139. ISSN 1409-2433.  http://dx.doi.org/10.15517/rmta.v30i1.50654.

In this survey article we study the propagation of ultrasonic waves in liquids with gas bubbles. These media are extremely nonlinear. A tiny void fraction changes the properties of the medium drastically. The gas bubbles not only produce high nonlinearity, but also introduce dispersive phenomena and attenuation that can be decisive for the ultrasonic behavior. Several results obtained by a numerical model previously developed (based on the finite-volume method in the space dimension and the finitedifference method in the time domain) are presented here, which allow us to analyze some complex effects associated with this problem. The model solves a differential system that couples the nonlinear oscillations of the bubbles and the acoustic field. We mainly focus on understanding how to enhance the generation of new frequencies (harmonics and subharmonics from a one-frequency source and sum and difference frequencies from a two-frequency source) taking into account some aspects such as cavity type, smoothing and optimization of the medium.

Keywords : Nonlinear acoustics; bubbly liquids; ultrasound; numerical models..

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