Acoustics and Dissolved Oxygen Induced by Bubbles during Drop Impact
Date Issued
2007
Date
2007
Author(s)
Hung, Wei-Tsung
DOI
zh-TW
Abstract
The impact of a droplet on a liquid surface can result in different fantastic phenomena. In our experiment, we use high-speed camera, hydrophone, and DO meter to catch the impact phenomenon, sound signals and the magnitude of dissolved oxygen, respectively.
Many investigations have been conducted since decades; however, very few have been studied for the floating bubble induced by the impacting droplet since Worthington (1908). In the present study, floating bubble induced by the droplet impact has been experimentally studied and analyzed. Effects of impact velocity, drop size, oscillation parameter and depth of target liquid have been investigated and discussed. The oscillation parameter, sharpness ratio e, of free-falling droplet, defined as the ratio of maximum length of droplet in the vertical to the horizontal direction before impact has been found to be one of the most important controlling parameters in the present study.
The phenomena of free falling drop impacting into the deep water and their corresponding mechanism to generate sound under water have been experimentally investigated in this paper. Comparing with previous studies by Pumphery and Elmore (1990), new characteristic mode “Penetrated Floating Bubbles” and new Mesler regimes in the v (impact velocity)—d(diameter of droplet) map have been discovered by using hydrophone and high-speed carmera for the sound and image analysis.
The maginitude of dissolved oxygen is measured for different impact modes. Some characteristic initial conditions will lead oxygen dissolved most instead of those with larger impact velocity, larger drop size and higher frequency of drop generation. Include DO, the two above mentioned paragraphs are the main three sections in our results and discussion.
Subjects
液滴撞擊型態
捲入氣泡
液滴振盪
漂浮氣泡
水下聲學
溶氧
drop impact
bubble entrainment
drop oscillation
floating bubble
underwater acoustics
Type
thesis
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