par Mikaelian, David ;Larcy, Aurélie ;Cockx, Arnaud ;Wylock, Christophe ;Haut, Benoît
Référence Experimental thermal and fluid science, 64, page (1-12)
Publication Publié, 2015-02-02
Article révisé par les pairs
Résumé : 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.