The effect of acoustic radiation in an ideal fluid on the viscosity of a drop

Authors

  • Oleksandr Zhuk S. P. Timoshenko Institute of Mechanics, NAS of Ukraine, Kyiv, Ukraine
  • Yaroslav Zhuk Taras Shevchenko National University of Kyiv
  • Maria Kashtalyan University of Aberdeen, Aberdeen, Scotland, UK

DOI:

https://doi.org/10.17721/1812-5409.2026/1.16

Keywords:

acoustic radiation force, spherical liquid drop, ideal compressible fluid, viscous fluid, plane harmonic wave, sound field

Abstract

The effect of acoustic radiation force on a spherical drop of viscous liquid, located in turn in an ideal liquid in a plane sound wave field, is investigated. Acoustic radiation force is a measure of the interaction between an incident acoustic wave and a drop of viscous liquid, defined as the time-averaged integral value of the sound pressure over the surface of the viscous drop. A procedure for solving the problem has been developed, which is implemented in two steps. At the first step, an approach was developed to determine the pressure, which involves the use of the velocity field potential obtained as a solution to the linear problem of incident wave scattering at an obstacle. When formulating the boundary conditions, the surface tension pressure of the drop was not taken into account, and its radius was considered constant, i.e., the case of small pulsation oscillations was considered. Satisfying the boundary conditions on the surface of a viscous drop and Sommerfeld's conditions at infinity, together with the use of the orthogonality property of Legendre polynomials, made it possible to obtain an infinite system of algebraic equations with respect to unknown coefficients in the Fourier series expansions of potentials. At the second step of solving the problem, the pressure and hydrodynamic force caused by the acoustic field were calculated using the found potentials. The subsequent averaging of the hydrodynamic force over time allowed us to calculate the acoustic radiation force directly. Numerical calculations were performed for the case where the external fluid is water and the drop is formed from a viscous fluid insoluble in water - glycerin. A series of calculations was performed for a set of values of the radius of the viscous drop. It was found that the acoustic radiation force is not a monotonic function of the incident wave frequency. In the case of a solid spherical particle, the direction of the radiation force, as is known, coincides with the direction of propagation of the acoustic wave. In the case of a viscous spherical drop, the direction of the radiation force can be either coincident with the direction of wave propagation or opposite to it. It has been found that there are frequencies of the incident wave that provide zero radiation force acting on the drop, which in this case is stationary.

Pages of the article in the issue: 126 - 129

Language of the article: Ukrainian

References

Cantrell, J. H. (2018). Acoustic radiation pressure in fluids. NASA/TM–2018-219806.

Doinikov, A. A. (2005). Bubble and Particle Dynamics in Acoustic Fields: Modern Trends and Applications. Research Signpost.

King, L. V. (1934). On the acoustic radiation pressure on spheres. Proceedings of Royal Society of London A, 147, 212–240. https://doi.org/10.1098/rspa.1934.0215

Kubenko, V., Yanchevskyi, I., & Ostos, O. (2025). Dynamic characteristics of an ideal compressible fluid excited by a spherical segment in a cylindrical cavity. Bulletin of Taras Shevchenko National University of Kyiv. Physical and Mathematical Sciences, 80(1), 64-70. https://doi.org/10.17721/1812-5409.2025/1.9

Zhuk, O. P., Zhuk, Y., & Klimchuk, T. (2023). On the Acoustic Radiation Force Affecting Two Liquid Drops Located in the Wave Field. Axioms, 12(10), 940. https://doi.org/10.3390/axioms12100940

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Published

2026-06-05

Issue

Section

Differential equations, mathematical physics and mechanics

How to Cite

Zhuk, O., Zhuk, Y., & Kashtalyan, M. (2026). The effect of acoustic radiation in an ideal fluid on the viscosity of a drop. Bulletin of Taras Shevchenko National University of Kyiv. Physics and Mathematics, 82(1), 126-129. https://doi.org/10.17721/1812-5409.2026/1.16

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