Bubble breakup reduced to a one-dimensional nonlinear oscillator
Résumé
Breaking dynamics of bubbles in turbulence produce a wide range of bubble sizes, which mediates gas transfer, in particular at the ocean/atmosphere interface. At the scales close to the stability limit of bubbles torn away by inertial forces, a typical geometry that induces bubble break-up is the uni-axial straining flow. In this configuration, the bubble shapes and their limit of stability have been studied theoretically and numerically near their equilibrium. Using numerical simulations, we investigate the bubble dynamics and break-up in such flows, starting from initial shapes far from equilibrium. We show that the break-up threshold is significantly smaller than the previous linear predictions and evidence that the break-up threshold depends on both the Reynolds number at the bubble size, and the initial bubble shape (ellipsoids). To rationalize the bubble dynamics and the observed thresholds, we propose a reduced model for the oblate/prolate oscillations (second Rayleigh mode) based on an effective potential that depends on the control parameters and the initial bubble shape. Our model successfully reproduces bubble oscillations, the maximal deformation below the threshold and the bubble lifetime above the threshold.
Fichier principal
bubble_stagnation.pdf (1.44 Mo)
Télécharger le fichier
cvgStudy.pdf (258.73 Ko)
Télécharger le fichier
lifetime.pdf (191.75 Ko)
Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Origine : Fichiers produits par l'(les) auteur(s)