Modeling of non-equilibrium effects in intermittency region between two phases

Abstract: This paper concerns modeling of the evolution of intermittency region between two weakly miscible phases due to temporal and spatial variations of its characteristic length scale. First, the need of a more general description allowing for the evolution of intermittency region is rationalized. Afterwards, results of the previous work (Wac{\l}awczyk T., 2017, On a relation between the volume of fluid, level-set and phase field interface models, Int. J. Multiphas. Flow, Vol. 97) are discussed in context of the sharp interface models known in the literature and insight into droplet coalescence mechanism recently recognized in the molecular dynamics studies (Perumanath S., Borg M.K., Chubynsky M.V., Sprittles J.E., Reese J.M., 2019, Droplet coalescence is initiated by thermal motion, Phys. Rev. Lett., Vol. 122). Finally, the physical and numerical models extending applicability of the equilibrium solution to the case when intermittency region could also be in the non-equilibrium state is introduced and verified in several test cases.