This work deals with a theoretical analysis about the possibility of using linear and\nnonlinear acoustic properties to modify ultrasound by adding gas bubbles of determined sizes in\na liquid. We use a two-dimensional numerical model to evaluate the effect that one and several\nmonodisperse bubble populations confined in restricted areas of a liquid have on ultrasound by\ncalculating their nonlinear interaction. The filtering of an input ultrasonic pulse performed by\na net of bubbly-liquid cells is analyzed. The generation of a low-frequency component from a\nsingle cell impinged by a two-frequency harmonic wave is also studied. These effects rely on the\nparticular dispersive character of attenuation and nonlinearity of such bubbly fluids, which can be\nextremely high near bubble resonance. They allow us to observe how gas bubbles can change acoustic\nsignals. Variations of the bubbly medium parameters induce alterations of the effects undergone by\nultrasound. Results suggest that acoustic signals can be manipulated by bubbles. This capacity to\nachieve the modification and control of sound with oscillating gas bubbles introduces the concept of\nbubbly-liquid-based acoustic metamaterials (BLAMMs).
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