Creation of a cluster of cavitation bubbles using diffusing droplets and its extension to sonoluminescence

目前的研究计划的目的是通过实验研究注入水中的粘性液滴如何在产生许多气泡方面发挥作用，这些气泡最终可能会导致单个气泡。正如纳赛尔·哈尔巴所指出的那样，这一过程复杂且难以管理。因此进行了更基本的研究1)粘性扩散液滴的流体动力学行为。首先，在没有超声波的情况下，甘油液滴从表面5 mm以上的位置落下，但只要其密度比溶液重0.02g/cm^3，液滴就会漂浮。扩散可能有助于获得浮力。其次，如果施加超声波，液滴会避开气泡被捕获的位置，这表明纳赛尔·哈巴煞费苦心地观察到了这些扩散过程。2)光散射数据和相关主题的分析。分析了由注入的甘油液滴形成的多个气泡的三次散射数据，假设气泡服从瑞利-普莱塞特方程。结果表明，散射数据受光饱和的影响较大。开发了用于分析气泡和液滴以及数字示波器上脉冲抖动的计算机程序，这可能会误导错误的时间序列信号。3)浓硫酸的声致发光。硫酸也是粘性的，从它产生的声致发光在几个频率上进行了研究。4)扩散液滴的莫尔云纹的数值模拟得到了水滴折射率分布的云纹，这可能模拟了液滴在水中的各向同性扩散。

The purpose of the present research program is to investigate experimentally how a viscous droplet, injected into water, plays a role in creating many bubbles, which may eventually result in a single bubble. The process is complicated and difficult to manage, as noted by Naser Harba. More fundamental investigation has thus been carried out.1)Hydrodynamical behavior of a viscous diffusing droplet.First, with no ultrasound droplets of glycerol were let fall from a position 5 mm above the surface, but the droplets floated as long as its density was heavier than the solution by less than 0.02 g/cm^3. Diffusion may have helped to gain the buoyancy. Next, if ultrasound was applied, the droplets evaded the position where bubbles were otherwise trapped, suggesting that Naser Harba painstakingly observed those diffusing processes.2)Analysis of light-scattering data and related subjects.Mie-scattering data for multiple bubbles formed from an injected glycerol droplet were analyzed, with the assumption that bubbles obeyed the Rayleigh-Plesset equation. It turned out that the scattering data were affected by saturation due to light. Computer programs were developed for analysis of bubbles and drops and for jittering of pulses on the digital oscilloscope, which may mislead to false time-train signals.3)Sonoluminescence from concentrated sulfuric acid.Sulfuric acid is also viscous, and sonoluminescence from it was investigated at several frequencies.4)Numerical simulation of Moire patterns for diffusing dropletsMoire patterns were produced for a distribution of refractive index, which might mimic droplets isotropically diffusing within water.