Optical and acoustic investigations of the dynamics of laser-produced cavitation bubbles near a solid boundary
Optical and acoustic investigations of the dynamics of laser-produced cavitation bubbles near a solid boundary
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DOI：
10.1017/s0022112089002314
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发表时间：
1989-09
影响因子：
3.7
通讯作者：
A. Vogel;W. Lauterborn;R. Timm
中科院分区：
文献类型：
--
作者：
A. Vogel;W. Lauterborn;R. Timm
实验研究了固体边界附近激光空化空泡的动力学特性及其与空泡与壁面距离的关系。通过高达100万帧/秒的高速摄影表明，射流和反射流的形成以及由射流引起的环形涡的发展是固体边界附近气泡动力学的一般特征。利用时间分辨粒子图像测速技术对空化泡附近的流体速度场进行了测量。由连续测量得到的轨迹线与Kucera & Blake（1988）的数值计算结果比较表明，两者吻合较好。利用水听器和光学探测技术测量了球形气泡溃灭和刚性边界附近溃灭过程中所产生的瞬态声信号的压力幅值、波形和能量。声发射是球形泡坍缩的主要阻尼机制，而非球形泡坍缩的阻尼机制中声发射的作用较小。声瞬变的持续时间为20-30 ns。在固体边界处的最高压力幅值已被发现的气泡附着到边界。当最大气泡半径为3.5 mm时，气泡内部和边界处的压力达到约2.5 kbar。
The dynamics of laser-produced cavitation bubbles near a solid boundary and its dependence on the distance between bubble and wall are investigated experimentally. It is shown by means of high-speed photography with up to 1 million frames/s that jet and counterjet formation and the development of a ring vortex resulting from the jet flow are general features of the bubble dynamics near solid boundaries. The fluid velocity field in the vicinity of the cavitation bubble is determined with time-resolved particle image velocimetry. A comparison of path lines deduced from successive measurements shows good agreement with the results of numerical calculations by Kucera & Blake (1988). The pressure amplitude, the profile and the energy of the acoustic transients emitted during spherical bubble collapse and the collapse near a rigid boundary are measured with a hydrophone and an optical detection technique. Sound emission is the main damping mechanism in spherical bubble collapse, whereas it plays a minor part in the damping of aspherical collapse. The duration of the acoustic transients is 20-30 ns. The highest pressure amplitudes at the solid boundary have been found for bubbles attached to the boundary. The pressure inside the bubble and at the boundary reaches about 2.5 kbar when the maximum bubble radius is 3.5 mm. The results are discussed with respect to the mechanism of cavitation erosion.