Theoretical and numerical study of air entrainment and bubble size distribution in strong free-surface turbulent flow at large Froude and Weber number
Name
1145019984-MIT.pdf
Size
13.55 MB
Format
Adobe PDF
Checksum (MD5)
5b762f95ac96742586a5c672e21d6b2c
Author(s)
Yu, Xiangming,1987-
Advisor(s)
Dick K. P. Yue.
Date Issued
2019
Publisher
Massachusetts Institute of Technology
Abstract
Strong turbulence near an air-water interface, characterized by large Froude (Fr) and Weber number (We), leads to significant interactions and exchanges between gas and liquid, resulting in measurable air entrainment. Air entrainment influences a number of physical processes in the nature, including air-sea gas transfer, production of the sea-salt aerosol and scavenging of biological surfactant. The key factor in controlling these processes is the size distribution of entrained bubbles. However, the underlying mechanisms/physics of air entrainment driven by free-surface turbulence (FST) and the resulted bubble size distribution still remain unclear. Therefore, detailed studies on air entrainment in strong free-surface turbulence (SFST) are of fundamental scientific interest. With recent interest in modeling the white bubbly water in ship wakes, these studies are also of practical importance to the design and analysis of modern surface vessels. In this thesis, we perform both theoretical and numerical studies on air entrainment and bubble size distribution in SFST at large Fr and We. The thesis work 1) characterizes the unique turbulence characteristics of SFST; 2) quantifies the entrainment volume and the corresponding size distribution of SFST air entrainment; 3) elucidates the mechanisms/physics of the bubble size distribution of SFST entrainment; 4) provides useful insight and guidance to the development of sub-grid air entrainment models ...
Description
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 189-192).
Subjects
Mechanical Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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