Abstract

Extraction of Higher Nonlinear Parameters/Virial Coefficients From Acoustic Measurements

I.Vereshchagina, S.Leble (Kaliningrad State University, Kaliningrad, Russia); K.Zakhariasz (Technical University of Gdansk, Gdansk, Poland)

e-mail: Vereshchagin2@theor.phys.albertina.ru; verid@mail.ru

Revisiting a derivation of KZK equation with cubic term [1], generalizing one of Nachef-Cathignol-Tjotta J.N.- Berg -Tjotta S. [2,3] that use the velocity potential, we arrive at different expression for nonlinearity coefficient as a function of adiabata expansion constants. Using results of Kunitsin-Rudenko perturbation theory foracoustic beam diffraction, we obtain analitical solutions for harmonics of the acoustic beam at some distance from a round flat source in the weak-dissipative medium with combined quadratic-cubic nonlinearity. Numerically evaluating the diffraction integrals, we plot amplitude profiles for first three harmonics with attenuation. Comparing the analitical results with experemintal data we estimate the value of the third virial coefficient for water. This value is in a good agreement with evalutions of others autors, which were made by means of thermodynamic relations. In other words, we suggest a method of experimental evaluation of the nonlinear parameters as B/A and C/A. [1]. Leble S.B., Vereshchagina I.S. Khokhlov - Zabolotskaya - Kuznetsov equation with cubic term and virial coefficients // Acta Acustica. 1999. V.85. P.685-690. [2]. Nachef S., Cathignol D., Tjotta J.N., Berg A.M., Tjotta S. Investigation of a high intensity sound beam from a plane transducer. Experimental and theoretical results // J. Acoust. Soc. Am. 1995. V.98. P.2303-2323. [3]. Berg A., Tjotta S. Higher order nonlinearity in ultrasound beam propagation.// in 20-th Scandinavian Symposium on Physical Acoustics, Ustaoset. 1997. P.5-7.

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