Bubble Nucleation, Growth, and Deformation in Shear Flows

Phase transitions in fluids can be drastically altered by shear flow. Bubble deformation and thermal growth are investigated numerically by means of a three-dimensional volume-of-fluid method. Furthermore, the asymptotic case of nucleation in extremely superheated liquids is treated in the framework of a continuum theory based on the Cahn–Hilliard gradient model. It is found that there is always an interesting distinction of the value π/4 for the flow-induced orientation angle in the case of small shear rates. For a great variety of viscosity and density ratios, the bubble deformation and even the break-up radius as a function of the corresponding capillary number are obtained. The growth process including non-equilibrium contributions is calculated, too. The results indicate that shear is able to completely suppress classical nucleation under certain circumstances.