Abstract
We measured the dispersion relation for acoustic longitudinal waves in liquid foams, over a broad frequency range (60–600 kHz). Strong dispersion was found, with two nondispersive behaviors, separated by a negative density regime. A new model, based on the coupled displacements of films, liquid channels, and gas in the foam, rationalizes all the experimental findings.
- Received 17 October 2013
DOI:https://doi.org/10.1103/PhysRevLett.112.148307
© 2014 American Physical Society
Focus
Stopping Sound with Foam
Published 11 April 2014
Liquid foams can completely block ultrasound transmission of some frequencies, suggesting that foams are metamaterials that could be used for acoustic insulation.
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