Publicado por JUAN MANUEL FERNANDEZ GARCIA el 27/01/2014 a las 12:43:13.

El profesor Daniel Fuster (CNRS-Institut D'Alembert, Universidad de Paris 6) impartirá un seminario el viernes 31 de enero 2014 a las 11:00 horas en el aula 009 de la ETSI.

Título: Modeling bubble clusters in compressible liquids

The behavior of bubble cluster is currently being object of an intense research due to its importance in various processes such as lithotripsy, water and crude oil treatment or underwater explosions. In this work we present a new model for bubbly cavitating flows. Based
on volume-averaged equations, a subgrid model is added to account for a bubble, or multiple
bubbles, within each computational cell. The model converges to the solution of ensemble-averaged bubbly flow equations for weak oscillations and monodisperse systems. In the other extreme, it also converges to the theoretical solution for a single oscillating bubble, and captures the bubble radius evolution and the pressure disturbance induced in the liquid. Compared to previous models based on volume and phase averaging, the new model extends the range of void fractions that can be reliably simulated and, for low enough void fractions, reproduces the results of the polydisperse phase-averaged model with much smaller
computational expense.

The new numerical results allow us to gain new insight into the effect of direct bubble-bubble interactions in the response of bubble
clusters. We show that it is possible to extend the classical linear theory of wave propagation in bubbly liquids [1] to account for the
effect of bubble-bubble interactions on the attenuation and the phase speed of acoustic waves. The results are tested against new simulation
results and also compared against data previously reported in the literature.

[1] K.W. Commander and A. Prosperetti, Linear pressure waves in bubbly
liquids: Comparison between theory and experiments. JASA, Vol. 85(1989)