Systems, methods, and computer-readable media for modeling slug flow. The method includes receiving a fluid flow model comprising a representation of one or more conduits and a multiphase fluid flow therein, and determining a slug birth rate in the multiphase fluid flow. The slug birth rate is determined based at least partially on a difference between a slug front velocity and a slug tail velocity. The method also includes initiating a slug in the fluid flow model based at least partially on the slug birth rate, and displaying data representative of the slug flow in the model.