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...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Final Year Project |
| Language: | English |
| Published: |
Nanyang Technological University
2021
|
| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/153577 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | 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. |
|---|