Existence of drops and bubbles in turbulence is granted by their interface. Interfaces are a macroscopic perception of molecular properties, are not property of the drop or the carrier fluid and their role is enormously important in a number of environmental and industrial processes: it is across interfaces that momentum, heat and mass transfer fluxes occur. In this talk, We will briefly review the physics modelling and the current computational methodologies used to track interfaces and we will focus on the phase-field approach, in which the phase distribution is a field described by the order parameter φ. We will present several flow instances and phenomena in which surface tension, density and viscosity are varied, and we will also cover the role of surfactants in altering topological changes of drops (breakage and coalescence) in connection with the characteristics of turbulence. Finally, we will examine the heat transfer between a dispersed phase of large deformable drops and a carrier fluid focusing on the flow structure inside the drops.
