arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2005.05733physics.flu-dyn
收藏

可压缩液体中固体边界附近气泡形成射流。距离依赖性的数值研究

Jet formation from bubbles near a solid boundary in a compressible liquid. Numerical study of distance dependence

Christiane Lechner, Werner Lauterborn, Max Koch, Robert Mettin

摘要:

一个小的,高内压的球形气泡插入到水中,在恒定的环境压力作为一个模型的激光诱导气泡。其随后的动力学在一个平坦的固体边界附近的依赖于气泡到边界的距离进行了研究,通过数值求解Navier-Stokes方程的帮助下的开源软件环境OpenFOAM。实现的是有限体积法离散的运动方程和流体的体积法捕捉气泡内部和外部之间的界面。气泡中含有少量的不可凝气体,被视为理想气体。液体是服从泰特方程的水。必要时包括表面张力。对于0到3之间的标准化距离$D^* = D/R_{\rm max}$($D^* = D/R_{\rm max}$ =气泡中心到边界的初始距离,$R_{\rm max}$ =气泡在没有任何边界的情况下将达到的最大半径),给出了气泡形状的演变以及压力和速度场的选择。选择$R_{\rm max} = 500 μ$ m进行研究。正常轴向射流形成($\sim 100$ m s $^{-1}$)的轴向流聚焦被发现为$0.24 \le D^* \le 3$和变化到一个不同类型的轴向射流形成($\sim 1000$ m s $^{-1}$)的环形液体流碰撞气泡非常接近固体边界($0 \le D^* \le 0.2$)。过渡区($0.2 < D^* < 0.24$)的特征在于附加的向内和向外的环形射流。值得注意的是,水的粘度是获得快速射流的决定性因素。

英文摘要:

A small, spherical bubble of high internal pressure is inserted into water at constant ambient pressure as a model of a laser-induced bubble. Its subsequent dynamics near a flat solid boundary is studied in dependence on the distance of the bubble to the boundary by numerically solving the Navier-Stokes equations with the help of the open source software environment OpenFOAM. Implemented is the finite volume method for discretization of the equations of motion and the volume of fluid method for capturing the interface between the bubble interior and exterior. The bubble contains a small amount of non-condensable gas that is treated as an ideal gas. The liquid is water obeying the Tait-equation. Surface tension is included where necessary. The evolution of the bubble shape and a selection of pressure and velocity fields are given for normalized distances $D^* = D/R_{\rm max}$ between 0 and 3 ($D$ = initial distance of the bubble centre to the boundary, $R_{\rm max}$ = maximum radius the bubble would attain without any boundary). $R_{\rm max} = 500 μ$m is chosen for the study. Normal axial jet formation ($\sim 100$ m s$^{-1}$) by axial flow focusing is found for $0.24 \le D^* \le 3$ and the change to a different type of axial jet formation ($\sim 1000$ m s$^{-1}$) by annular-liquid-flow collision for bubbles very near to the solid boundary ($0 \le D^* \le 0.2$). The transition region ($0.2 < D^* < 0.24$) is characterized by additional inbound and outbound annular jets. Remarkably, the inclusion of the viscosity of the water is decisive to get the fast jets.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑