Which flow profile describes a uniform velocity across the cross-section?

Which flow profile describes a uniform velocity across the cross-section?

• A. Parabolic flow profile
• B. Laminar flow profile
• C. Plug flow profile
• D. Spectral broadening flow profile

Answer: (C)

Uniform velocity across the cross-section is described by a plug flow profile. In this picture, every part of the cross-section moves at the same speed, so there’s no velocity gradient across the radius and little to no shear between layers. This idealization occurs when transverse mixing is very fast, effectively turning the cross-section into a single moving "plug." Parabolic flow, in contrast, has the center moving fastest and the edges slowest, a result of viscous forces in pipe flow under laminar conditions. Laminar flow refers to the smooth, orderly regime, but within a circular pipe it often yields that parabolic shape rather than a flat profile. The term spectral broadening flow profile isn’t a standard description of velocity distribution in fluids. So the flat, uniform cross-sectional velocity is best captured by plug flow.

Uniform velocity across the cross-section is described by a plug flow profile. In this picture, every part of the cross-section moves at the same speed, so there’s no velocity gradient across the radius and little to no shear between layers. This idealization occurs when transverse mixing is very fast, effectively turning the cross-section into a single moving "plug." Parabolic flow, in contrast, has the center moving fastest and the edges slowest, a result of viscous forces in pipe flow under laminar conditions. Laminar flow refers to the smooth, orderly regime, but within a circular pipe it often yields that parabolic shape rather than a flat profile. The term spectral broadening flow profile isn’t a standard description of velocity distribution in fluids. So the flat, uniform cross-sectional velocity is best captured by plug flow.