Rigorous two-phase flow modeling is one of the great challenges in the classical sciences. As with most problems in engineering, the interest in two-phase flow is due to its extreine importance in various industrial applications. Two-phase computational fluid dynamics (CFD) calculations, using Eulerian-Eulerian model. and commercial CFD package FLUENT 6.0, were employed to calculate the gas-liquid flow in pipes. Variables studied include: gas velocity, volume fraction of liquid and interfacial roughness. The gas velocity was varied from 1.2 to 12.5 m/s. The liquid velocity was taken as 0.0066 and 0.1 m/s. The numerical results were validated against experimental data from the literature. The prediction of the shear stress distribution and flow profile characteristics were within an average error of about 10%. The simulations validate the concept of interfacial roughness to account for gas-liquid interactions. A comparison of experimental and computed profiles was found to be in good agreement. Based on the extensive numerical computations, the flow field characteristics are explored and a correlation of (f(i)/f(w)) in wavy stratified flow regime has been presented. (c) 2005 Elsevier B.V. All fights reserved.