Studies of fluid flow in annular pipes have been popular in the petroleum engineering research. Most of the work has concentrated on CFD (Computational Fluid Dynamics) simulations, analytical and empirical models. In this study a neural network and evolutionary programming approach is developed to model the behavior of fluid flow in eccentric pipes. The model uses the fluid rheological parameters, density, mass flow rate, eccentricity, inner and outer pipe diameters, and predicts the pressure drop (ΔP) in the pipe in the flow direction. The evolutionary programming model uses basic mathematical operators, logarithm and sine functions. The results are compared with...