Time-domain simulation of acoustic wave scattering and internal propagation from gas bubbles of various shapes

• Published in: The Journal of the Acoustical Society of America 2020-10, Vol.148 (4), p.2495-2495
• Main Authors: Hou, Jiacheng, Zheng, Zhongquan C., Allen, John S.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.5146916

Acoustic scattering and resonances of incident waves from a gas bubble are simulated using a time-domain simulation based on numerical solutions of the conservation laws. The time histories of scattering pressure and velocity, both outside and inside the bubble, are obtained simultaneously from an immersed-boundary method facilitating the investigation of both exterior and interior fields for complex geometries. The acoustic resonances of the bubble are investigated for various bubble sizes, shapes and inner gas parameters and compared to the partial wave scattering solutions for spherical bubbles. Agreement is shown with the analytical solutions in the linear acoustic limit. The resonance frequency increases with the bubble's inner background pressure and independent of the incident wave amplitude or frequency. In addition to scattering outside of the bubble, acoustic propagation inside the bubble is investigated with respect to the monopole resonance. A significant advantage is that this time-domain simulation combined with the immersed-boundary method can be readily adapted for various shapes of bubbles including oblate or prolate. The scattering and resonance behaviors are simulated and compared with the analytical results involving a shape factor and extended for previously less investigated shapes of significance to underwater and physical acoustics applications including “pancake shaped” bubbles.