School of Mechanical Engineering Seminar
Wednesday,28 November, 2012 at 15:00
Wolfson Building of Mechanical Engineering, Room 206

Laminar Two-Phase Separated Flows:

Analytical Solutions and Mechanistic Models

Ayelet Goldstein

PhD Student of Prof. Neima Brauner and Prof. Amos Ullmann

Exact solutions for separated two-phase flow are useful as benchmark for numerical codes and for testing closure relations for simplified 1D Two-Fluid (TF) models. Recently we obtained a complete set of exact solutions for laminar flows in inclined pipes. These include all possible configurations of stratified flows (STF) with concave and convex interfaces, and core-annular flows (CAF) with various core eccentricities. The exact solutions are used to analyze the local and averaged wall and interfacial shear stresses for these various flow geometries. A closed-form analytical expression for the average interfacial shear stress was obtained for all cases of STF. The limiting behavior of the local shear stresses at the triple-point, where the interface meets the pipe wall, is determined by residue calculus. It is shown that the shear stresses profiles at the vicinity of the triple points are determined by the fluids viscosity ratio and the contact angle. The usefulness of the exact solutions for testing closure for approximate TF models is discussed.