On differences between deterministic and statistical models of the interphase region

Abstract

This paper reviews differences between the deterministic (sharp and diffuse) and statistical models of the interphase region between the two-phases. In the literature this region is usually referred to as the (macroscopic) interface. Therein, the mesoscopic interface that is defined at the molecular level and agitated by the thermal fluctuations is found with nonzero probability. For this reason, in this work, the interphase region is called the mesoscopic intermittency/transition region. To this purpose, the first part of the present work gives the rationale for introduction of the mesoscopic intermittency region statistical model. It is argued that classical (deterministic) sharp and diffuse models do not explain the experimental and numerical results presented in the literature. Afterwards, it is elucidated that a statistical model of the mesoscopic intermittency region (SMIR) combines existing sharp and diffuse models into a single coherent framework and explains published experimental and numerical results. In the second part of the present paper, the SMIR is used for the first time to predict equilibrium and nonequilibrium two-phase flow in the numerical simulation. To this goal, a two-dimensional rising gas bubble is studied; obtained numerical results are used as a basis to discuss differences between the deterministic and statistical models showing the statistical description has a potential to account for the physical phenomena not previously considered in the computer simulations.