Two-dimensional modeling for stability analysis of two-phase stratified flow

The effect of wavelength and relative velocity on the disturbed interface of two-phase stratified regime is modeled and discussed. To analyze the stability, a small perturbation is imposed on the interface. Growth or decline of the disturbed wave, relative velocity, and surface tension with respect to time will be discussed numerically. Newly developed scheme applied to a two-dimensional flow field and the governing Navier-Stokes equations in laminar regime are solved. Finite volume method together with non-staggered curvilinear grid is a very effective approach to capture interface shape with time. Because of the interface shape, for any time advancement, a new grid is performed separately on each stratified field, liquid, and gas regime. The results are compared with the analytical characteristics method and one-dimensional modeling. This comparison shows that solving the momentum equation including viscosity term leads to physically more realistic results. In addition, the newly developed method is capable of predicting two-phase stratified flow behavior more precisely than one-dimensional modeling. It was perceived that the surface tension has an inevitable role in dissipation of interface instability and convergence of the two-phase flow model. Copyright (C) 2009 John Wiley & Sons, Ltd.