基于边界元法的近平板圆孔气泡动力学行为研究

Study on bubble dynamics near plate with hole based on boundary element method

研究了带有圆孔的平板附近气泡动力学特性.基于不可压缩势流理论,建立了平板圆形破口附近气泡运动数值模型,并针对气泡初始位置距离破口很近而导致计算结果发散的数值缺陷,采用气泡壁和壁面融合的方法,将流场分离为两个半无限域问题进行求解,实现了在不同无量纲参数范围内的数值模拟,数值结果与实验结果符合良好.通过对圆孔附近气泡运动特性的研究发现,圆孔对气泡的影响基本与壁面相反,在膨胀阶段对气泡产生腔吸作用,收缩阶段产生排斥,在特定的工况下会产生对射流现象.最后分析了气泡壁与壁面融合,流场分离后的气泡动态特性以及各工况参数对其影响规律.

In this work the bubble dynamics near a plate with circular hole is investigated. Numerical model for bubble dynamics is established based on incompressible potential theory. To overcome the numerical limitation of traditional boundary element method for the case with small initial distance between bubble and the edge of hole, the fluid domain is divided into two semi-infinite domains which are solved separately by fusing the bubble wall and the plate wall together, by which numerical simulation in various parameter ranges is implemented. The numerical results match the experimental ones well. Through the analysis of bubble dynamics near circular hole, we find that the influence of hole is opposite to that of solid wall. During the expansion phase, cavity-attraction effect is exerted on the bubble, while the bubble is pushed away during the collapsing phase. In some specific cases, opposite-jets are formed under the conjunction of solid plate and circular hole. Finally, the case where bubble wall and solid wall are fused together is analyzed to study the bubble dynamics after the separation of fluid domain and the influences of no-dimensional parameters.