A parabolic flow profile is seen with which flow state?

• A. Distal to a stenosis
• B. Small veins
• C. Laminar flow
• D. Disturbed flow

Answer: (C)

Parabolic flow profile describes steady, fully developed laminar flow in a long straight tube, where viscosity smooths the motion into concentric layers that slide past each other. The no-slip condition at the wall makes the velocity drop to zero at the boundary, while the center runs fastest, producing the classic parabolic shape. After a stenosis, flow becomes jet-like and downstream there are recirculation zones and disturbances, so the velocity profile is no longer parabolic. While laminar flow can occur in small veins under certain conditions, the characteristic parabolic cross-section is the hallmark of ideal, steady laminar flow in a straight vessel, unlike disturbed or highly nonuniform flows.