气泡群的动态物理特性研究

假设气泡周围流场为无黏、无旋、不可压缩的理想流体，建立气泡群相互作用的三维数值模型.将多极快速傅里叶变换方法(FFTM)与高阶边界元法(HOBEM)相结合求解气泡群的运动，在达到同样计算精度时显著加快了边界积分方程的求解速度，可以在合理的时间内模拟气泡群的动态物理特性.同时为维持气泡群模拟过程中的数值稳定性，引入了弹性网格技术(EMT)，并用算例验证了数值模型及算法的有效性.基于建立的数值模型，研究了不同组合的气泡群之间的相互作用，模拟和解释了各类气泡运动的物理现象，讨论了影响气泡群膨胀、坍塌、迁移及射流 关键词： 气泡群 FFTM 射流 三维

The dynamics of bubbles

The fluid is assumed to be inviscid and incompressible and the flow irrotational. The three_dimensional numerical model is established to simulate the interaction of multiple bubbles and the fast Fourier transform on multipoles (FFTM) method is combined with the higher order boundary method (BEM) to study the physics of multiple bubble dynamics. FFTM method is employed to speedup the solution of the boundary integral equation while achieving the same order of accuracy, enabling to simulate the dynamics of multiple bubbles in a reasonable time. Elastic mesh technique (EMT), which is a new mesh regulation technique, is applied to maintain the regularity of the triangular element mesh used to discretize the dynamic boundary surface during the evolution of bubbles. All these measures make the present approach viable and robust, which is validated by computations of several bubble dynamics problems. Numerical analysi was carried out for the interaction of multiple bubbles and the bubble dynamics. Some physical behaviors of the multiple bubbles are presented in this work. The factors affecting the expansion, collapse, moving of multiple bubbles and the jet formation are also discussed.