Dynamics and morphology of single ellipsoidal bubbles in liquids

作者：Mikaelian David; Larcy Aurelie; Cockx Arnaud; Wylock Christophe; Haut Benoit^*

来源：Experimental Thermal and Fluid Science, 2015, 64: 1-12.

DOI：10.1016/j.expthermflusci.2015.01.013

• Ellipsoidal bubbles
• Shadowgraphy
• Oscillatory trajectory
• Curvature
• Correlation

A data postprocessing method for an imaging technique based on shadowgraphy is presented in this paper. It enables a precise analysis of the dynamics of a bubble rising in a liquid. The morphology of the bubble is also precisely analyzed by determining an appropriate threshold for the binarization of the images. Experiments with single ellipsoidal bubbles rising in various water-glycerol mixtures, with an oscillatory trajectory and without interface wobbling, are analyzed. It is rigorously shown that the minor axis and the mass center velocity vector of a bubble are aligned in the cases of a zigzag and a helical motion of the bubble. The interface curvature radii at the front and at the rear of a bubble are determined and, in the case of a zigzag motion of the bubble, a correlation to calculate their ratio is proposed. In the vertical motion of the mass center of a bubble, a pulsation at twice the frequency of its horizontal motion is identified in the case of a zigzag motion of the bubble. In the case of a helical motion of a bubble, such a pulsation cannot be identified in the vertical motion of the mass center of the bubble.

• 出版日期2015-6
• 单位河南工业大学