Bubble formation in lattice Boltzmann immiscible shear flow.

Bubble formation and the effect of shear on bubble formation in a van der Waals fluid is investigated by means of lattice Boltzmann mesoscale simulations. In the absence of shear, the maximum number of formed bubbles increases with undercooling but the incubation time before bubble formation decreases dramatically. The results are in agreement with classical phase transition theory. In shear flow, the maximum number of bubbles is not affected by shear but the bubble growth rate is accelerated. The effect of shear on bubble growth rate weakens at large undercoolings. The reasons are twofold. On the one hand the highly undercooled system takes less time to complete phase transition due to the large driving force so that there is less time to accumulate the flow effect. On the other hand the mechanism for bubble growth changes from coarsening to coalescence at large undercoolings.