Characteristic of bubble rise in quiescent liquids

The shapes and trajectories of a rising bubble in a column of water are studied experimentally, using videography and image processing algorithms to obtain its position and dimensions. The experiments were conducted by varying the bubble diameters ranging from 3.6mm to 10.5mm, corresponding to a...

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Main Author: Tan, Jing Heng
Other Authors: Chiew Yee Meng
Format: Final Year Project (FYP)
Language:English
Published: Nanyang Technological University 2021
Subjects:
Online Access:https://hdl.handle.net/10356/153577
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author Tan, Jing Heng
author2 Chiew Yee Meng
author_facet Chiew Yee Meng
Tan, Jing Heng
author_sort Tan, Jing Heng
collection NTU
description The shapes and trajectories of a rising bubble in a column of water are studied experimentally, using videography and image processing algorithms to obtain its position and dimensions. The experiments were conducted by varying the bubble diameters ranging from 3.6mm to 10.5mm, corresponding to a Reynolds number between 1700 to 5000. Familiar bubble trajectories such as the zigzag and helical motion were observed, and an inverse relationship could be seen between bubble diameter and aspect ratio. Further data analysis showed that a rising bubble possesses terminal velocity, with minor fluctuations about a mean value. The plot of drag coefficient against Reynolds number also described a slight upward trend for Reynolds number between 1700 and 17000, where the drag coefficient of the bubble is generally higher than that of a solid smooth sphere, due to the increased form drag brought about by its ellipsoidal shape. This empirical model forms a basis for the derivation of a logarithmic regression equation to describe the relationship between a bubble’s shape and terminal velocity.
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spelling ntu-10356/1535772021-12-08T00:37:06Z Characteristic of bubble rise in quiescent liquids Tan, Jing Heng Chiew Yee Meng School of Civil and Environmental Engineering CYMCHIEW@ntu.edu.sg Engineering::Civil engineering The shapes and trajectories of a rising bubble in a column of water are studied experimentally, using videography and image processing algorithms to obtain its position and dimensions. The experiments were conducted by varying the bubble diameters ranging from 3.6mm to 10.5mm, corresponding to a Reynolds number between 1700 to 5000. Familiar bubble trajectories such as the zigzag and helical motion were observed, and an inverse relationship could be seen between bubble diameter and aspect ratio. Further data analysis showed that a rising bubble possesses terminal velocity, with minor fluctuations about a mean value. The plot of drag coefficient against Reynolds number also described a slight upward trend for Reynolds number between 1700 and 17000, where the drag coefficient of the bubble is generally higher than that of a solid smooth sphere, due to the increased form drag brought about by its ellipsoidal shape. This empirical model forms a basis for the derivation of a logarithmic regression equation to describe the relationship between a bubble’s shape and terminal velocity. Bachelor of Engineering (Civil) 2021-12-08T00:37:06Z 2021-12-08T00:37:06Z 2021 Final Year Project (FYP) Tan, J. H. (2021). Characteristic of bubble rise in quiescent liquids. Final Year Project (FYP), Nanyang Technological University, Singapore. https://hdl.handle.net/10356/153577 https://hdl.handle.net/10356/153577 en WR-21 application/pdf Nanyang Technological University
spellingShingle Engineering::Civil engineering
Tan, Jing Heng
Characteristic of bubble rise in quiescent liquids
title Characteristic of bubble rise in quiescent liquids
title_full Characteristic of bubble rise in quiescent liquids
title_fullStr Characteristic of bubble rise in quiescent liquids
title_full_unstemmed Characteristic of bubble rise in quiescent liquids
title_short Characteristic of bubble rise in quiescent liquids
title_sort characteristic of bubble rise in quiescent liquids
topic Engineering::Civil engineering
url https://hdl.handle.net/10356/153577
work_keys_str_mv AT tanjingheng characteristicofbubbleriseinquiescentliquids