Affiliation:
1. Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan
Abstract
The nonlinear dynamics of a spherical bubble cloud with nuclei size distribution are studied numerically. The spectrum of nuclei is assumed uniform initially. The simulations employ a nonlinear continuum bubbly mixture model with consideration of the presence of bubbles of different sizes. This model is then coupled with the Rayleigh-Plesset equation for the dynamics of bubbles. A numerical method based on the integral representation of the mixture continuity and momentum equations in the Lagrangian coordinates is developed to solve this set of integro-differential equations. Computational results show that the nuclei size distribution has significant effects on the cloud dynamics in comparison to the results for a single bubble size. One important effect is that the bubble collapse is always initiated near the surface of the cloud, even if the cloud has a very small initial void fraction. This effect has an important consequence, namely that the geometric focusing of the bubbly shock wave is always a part of the nonlinear dynamics associated with the collapse of a spherical cloud with nuclei size distribution. The strength of the shock and the oscillation structure behind the shock front are suppressed due to the effects of multiple bubble sizes. Far-field acoustic pressures radiated by two bubble clouds, one of equal-size bubbles and the other with bubble size distribution, are also compared. It is found that the cloud containing bubbles of different sizes emits a larger noise than the cloud of identical bubbles. Explanations for this effect are also presented.
Reference39 articles.
1. Bark, G., 1985, “Developments of Distortions in Sheet Cavitation on Hydrofoils,” Proceedings of the ASME International Symposium on Jets and Cavities, pp. 470–493.
2. Bark, G., and Berlekom, W. B., 1978, “Experimental Investigations of Cavitation Noise,” Proceedings of the 12th ONR Symposium on Naval Hydrodynamics, pp. 470–493.
3. Ceccio S. L. , and BrennenC. E., 1991, “Observations of the Dynamics and Acoustics of Travelling Bubble Cavitation,” Journal of Fluid Mechanics, Vol. 233, pp. 633–660.
4. Chapman R. B. , and PlessetM. S., 1971, “Thermal Effects in the Free Oscillation of Gas Bubbles,” ASME Journal of Basic Engineering, Vol. 93, pp. 373–376.
5. Commander K. W. , and ProsperettiA., 1989, “Linear Pressure Waves in Bubbly Liquids: Comparison between Theory and Experiments,” Journal of the Acoustical Society of America, Vol. 85, pp. 732–746.
Cited by
29 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献