Slug flow is a type of which flow regime?

• A. Intermittent flow
• B. Segregated flow
• C. Distributive flow
• D. Annular flow

Answer: (A)

In two‑phase pipe flow, the arrangement of gas and liquid as the mixture moves through a pipe is described by flow regimes. Slug flow forms when large pockets of gas move along the pipe with thick slugs of liquid in between. This pattern alternates over time—gas pockets followed by liquid slugs—so the flow is intermittent in nature. That alternating, time‑varying structure is why slug flow is classified as a type of intermittent flow regime. It’s not the same as annular flow, where a continuous gas core is separated from a thin liquid film along the walls, nor as segregated flow, where the phases occupy distinct regions more continuously across the cross-section. Distributive flow isn’t the standard description for this alternating pattern.