| FUNDAMENTAL AREAS OF PHENOMENOLOGY(INCLUDING APPLICATIONS) |
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Sound Velocity in Soap Foams |
| WU Gong-Tao, LÜ Yong-Jun, LIU Peng-Fei, LI Yi-Ning, SHI Qing-Fan** |
School of Physics, Beijing Institute of Technology, Beijing 100081
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| Cite this article: |
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WU Gong-Tao, Lü Yong-Jun, LIU Peng-Fei et al 2012 Chin. Phys. Lett. 29 104301 |
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Abstract The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference method. It is found that the sound velocities increase with increasing bubble diameter, and asymptotically approach to the value in air when the diameter is larger than 12.5 mm. We propose a simple theoretical model for the sound propagation in a disordered foam. In this model, the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional length. This simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the experiments. Further measurements indicate that the increase of frequency markedly slows down the sound velocity, whereas the latter does not display a strong dependence on the solution concentration.
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Received: 08 June 2012
Published: 01 October 2012
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| PACS: |
43.35.Ae
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(Ultrasonic velocity, dispersion, scattering, diffraction, and Attenuation in gases)
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43.20.+g
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(General linear acoustics)
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82.70.Rr
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(Aerosols and foams)
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