> C. Ruyer-Quil
Experimental study of path instability of rising bubbles
Viswa Maitreyi Moturi (ICUBE)
The main objective is to study the instability of a freely ascending air bubble in water and silicon oil at varied Bond numbers (ratio of body forces to surface tension) and Galileo numbers (ratio of gravitational force to viscous force). Below a certain threshold of the Galileo number, the path of the bubble remains straight and vertical and the bubble keeps an axisymmetric shape. Above a critical Galileo number (related to the size of the bubble) a new regime sets in. The bubble shape and its path start to oscillate.
Our work is focused on this new regime. Bubbles of different sizes are released into quiescent fluid and their paths are observed using high precision camera. The images obtained are post processed using the image processing processing tools of MATLAB to determine the size of the bubbles and to reconstitute their trajectory in the fluid. The Bond and Galileo numbers are calculated based on the size of the bubble and the physical properties of the used working liquids, water and silicon oil.