The present work, addressing a chronic industrial issue, provides numerical prediction of flow patterns of two-phase flow (oil-water) flowing in pipelines under certain design parameters by using a commercial model that shows good matching results with the experimental work in this field. It aims to provide preventive measures and control that can reduce pipelines and equipment' failures due to the phases' separation and reduce related costs. Moreover, success in simulating such complicated flow helps to avoid/reduce full or partial such expensive experimental work in this field. However,...