Bubble pulsation characteristics in multi-bubble systems affected by bubble size polydispersity and spatial structure

• Published in: Ultrasonics 2023-09, Vol.134, p.107089-107089, Article 107089
• Main Authors: Zou, Qingqin, Zhong, Xianhua, Zhang, Bingyu, Gao, Angyu, Wang, Xia, Li, Zhangyong, Qin, Dui
• Format: Article
• Language: English
• Subjects: Bubble pulsations; Bubble size polydispersity; Multi-bubble system; Two-dimensional structure of bubbles; Viscoelastic tissues
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2023.107089

•Size polydispersity and configuration of bubbles notably affect bubble pulsations.•Both amplitude and nonlinearity of bubble pulsations are suppressed.•Effect of size polydispersity is strong regardless of inter-bubble distances.•Two-dimensional structure of bubbles has great effects at small inter-bubble distances.•Larger bubbles nearby or smaller inter-bubble distances result in stronger effects. This study seeks to explore the bubble pulsation characteristics in multi-bubble environment with a special focus on the influences of the size polydispersity and the two-dimensional structure of bubbles. Three representative configurations of three interacting bubbles are formed by setting the initial radii of cavitation bubbles and inter-bubble distances appropriately, then the pulsation characteristics of a small bubble are investigated and compared by the bifurcation analysis. The results illustrate that the bubble size polydispersity and two-dimensional structure would greatly affect the bubble pulsations (i.e., the amplitude and nonlinearity of pulsations). Furthermore, the effects of two-dimensional structure are strong at a small inter-bubble distance of the large and small bubbles while the bubble size polydispersity always significantly affects the bubble pulsations for all cases. Moreover, the influences of both bubble size polydispersity and two-dimensional structure can be enhanced as the acoustic pressure increases, which can also become stronger when the large bubble is located at the same side as the small bubble and the initial radius of large bubble increases. Additionally, the effects would also be increased when the tissue viscoelasticity varies within a certain range. The present findings shed new light on the dynamics of multiple polydisperse microbubbles in viscoelastic tissues, potentially contributing to an optimization of their applications with ultrasound excitation.