Archives of Acoustics,
14, 3-4, pp. 283-292, 1989
Acoustic properties of gas bubbles coated with monolayers of oil substance
A gas bubble coated with a monolayer of oil substance, submerged in liquid, in the field of an acoustic wave is given theoretical consideration in this paper. Radial oscillations in the wave frequency band much below the resonance frequency depend mainly on the value of the monolayers modulus of elasticity and relaxation time t_r of the process of molecule
reorientation which occurs in the monolayer due to its deformation. The following parameters were calculated: shift of the resonance frequency, damping constant of radial oscillations, and acoustic wave scattering and extinction cross-sections for a gas bubble in water, coated with a condensed monolayer of Extra 15 engine oil in angular frequency range
ω ∈ [10^1 ÷ 10^5] rads^{-1} and range of radii of bubbles (3-50) μm. Predicted values of the damping constant and extinction cross-section in the wave frequency range ω < α(α = 2π/t_r) are by several orders of magnitude greater than those for a bubble with a clean srface. This
effect is especially distinct in the case of microbubbles (with μm radii and smaller) placed at small depths (up to about 0.5 m).
reorientation which occurs in the monolayer due to its deformation. The following parameters were calculated: shift of the resonance frequency, damping constant of radial oscillations, and acoustic wave scattering and extinction cross-sections for a gas bubble in water, coated with a condensed monolayer of Extra 15 engine oil in angular frequency range
ω ∈ [10^1 ÷ 10^5] rads^{-1} and range of radii of bubbles (3-50) μm. Predicted values of the damping constant and extinction cross-section in the wave frequency range ω < α(α = 2π/t_r) are by several orders of magnitude greater than those for a bubble with a clean srface. This
effect is especially distinct in the case of microbubbles (with μm radii and smaller) placed at small depths (up to about 0.5 m).
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References
A. ADAMSON, Physical Chemistry of Surfaces, John Wiley and Sons, New York 1976.
A. M. AVENESOV, I. A. AVETISYAN, Effect of polymer additives on sound propagation in water containing bubbles, Sov. Phys. Acoust., 22, 5, 359-370 (1976).
R. L. BENDURE, R. S. HANSEN, Damping of waves on monolayer covered surfaces, J. Phys. Chem. 71, 10, 2889-2997 (1967).
M. CESCHIA, R. NABERGOJ, On the motion of a nearly spherical bubble in a viscous liquid, Phys. Fluids, 21, 1, 140-142 (1978).
C. S. CLAY, H. MEDWIN, Acoustical oceanography, principles and applications, Wiley and Sons, London 1977.