A new experimental method to analyze the dynamics and the morphology of bubbles in liquids: Application to single ellipsoidal bubbles

• The dynamics and the morphology of ellipsoidal bubbles are investigated.
• An experimental set-up based on the use of two lenses is presented.
• An original data posttreatment method is developed.
• The precision and the accuracy of the results are discussed.
• Correlations are established.

An experimental set-up and a data posttreatment method are developed in order to analyze the dynamics and the morphology of bubbles rising freely in liquids. The set-up is used to generate single ellipsoidal bubbles in a water–glycerol mixture and to analyze their dynamics and their morphology for Eötvös numbers between 0.8 and 8 and Morton numbers between 10−1110−11 and 10−710−7. The water used is obtained by reverse osmosis. For the generated ellipsoidal bubbles, the posttreatment method allows investigating the presence (or not) of a wobbling of their interface and the nature of their trajectory, and mapping them as a function of their Eötvös and Morton numbers. For generated ellipsoidal bubbles having a helical motion without wobbling of their interface, a scaled amplitude and a scaled frequency of this helical motion, a deformation of these bubbles, and their Reynolds, Eötvös and Morton numbers are computed by the data posttreatment method. Correlations are established.