非球对称单气穴声致发光问题的直接数值模拟

Single-bubble sonoluminescence occurs when an acoustically trapped and periodically driven gas bubble collapses so strongly that the energy focusing at collapse leads to light emission. It had caught the attentions of researchers in physics, acoustics mechanics, chemistry and so on. Since the 90s of last century when the sonoluminescence phenomenon was discovered, many works on sonoluminescence has been published in high impact periodicals as Nature and Science. However, because of the critical condition of sonoluminescence (ultrasonic collapse, high energy focusing) and difficulties in experiments, researchers have not observed the status inside the bubble. In this project, by improving the definition of interfacial Riemann problem, the ghost fluid method and level set method will be extended to simulate one oscillation cycle of non-spherical single bubble sonoluminescence, the effect of phase change and surface tension will also be taken into accouont. We expect to obtain the bubble radius evolution process and predict the value of parameters like temperature and pressure. By comparison to present experimental and computational results, we want to get a more reasonable explanation of sonoluminescence phenomenon.

声致发光现象，即液体中受超声波辐射的气泡剧烈振动以致产生微弱光辐射的现象，近些年来引起多个学科（物理，声学，力学，化学等）研究者的关注。自上世纪90年代初单个气泡声致发光现象被报道以来，有关声致发光问题的研究工作不时见诸于《Nature》和《Science》等高影响力期刊。但声致发光现象的极端性质（如超声速塌缩﹑高能量集中）和实验测量的困难，使得人们至今还没观测到气泡内部的情况。本项目中，将发展计及表面张力和蒸发效应的修正Riemann问题，进而将虚拟流体方法和水平集方法应用于含相变和表面张力效应的非球对称单气穴声致发光问题的数值模拟，对气泡形态和气泡内部的温度等参数进行预测，并采用预处理Roe格式提高算法对低马赫数阶段的计算效率。最后将计算结果与现有的实验和计算结果相比较，得到对声致发光现象更合理的认识。