TRANSIENT SIMULATION OF 2D AND 3D STRATIFIED AND INTERMITTENT 2-PHASE FLOWS .1. THEORY

Stratified and intermittent stratified-bubble (slug) flows are complex phenomena, often requiring transient 2D and 3D descriptions. This paper presents the physical basis of a new type of multidimensional two-fluid model, particularly suited for transient flow problems. Important constitutive relations for wall shear stress and interfacial momentum transfer with necessary assumptions and simplifications are discussed. The numerical method is based on an implicit finite difference scheme, solved directly in two steps applying a separate equation for the pressure. The model has been verified through extensive comparisons with available experimental data as well as through comparisons with other models.