Laminar flow occurs when gas flows down parallel-sided tubes at rates below the critical velocity. Which statement best describes this condition?

Laminar flow occurs when gas flows down parallel-sided tubes at rates below the critical velocity. Which statement best describes this condition?

• A. Above the critical velocity
• B. At the critical velocity
• C. Below the critical velocity
• D. In turbulent regime

Answer: (C)

Laminar flow is the smooth, orderly motion of fluid layers that slide past one another without chaotic mixing. This happens when the flow velocity is low enough that viscous forces dominate over inertial forces, keeping the Reynolds number in a range that supports orderly flow. The threshold at which flow can transition to turbulence is the critical velocity. Below that threshold, the flow remains laminar; above it, disturbances grow and the flow becomes turbulent. At the exact critical velocity, the flow is at the edge of transition, not reliably laminar. So the statement describing laminar flow best is that it occurs below the critical velocity.

Laminar flow is the smooth, orderly motion of fluid layers that slide past one another without chaotic mixing. This happens when the flow velocity is low enough that viscous forces dominate over inertial forces, keeping the Reynolds number in a range that supports orderly flow. The threshold at which flow can transition to turbulence is the critical velocity. Below that threshold, the flow remains laminar; above it, disturbances grow and the flow becomes turbulent. At the exact critical velocity, the flow is at the edge of transition, not reliably laminar. So the statement describing laminar flow best is that it occurs below the critical velocity.