Flow in Pipes

The fourth-power law

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Fluid at the wall is stationary; smooth pipe flow has a parabolic speed profile.
• Poiseuille: flow $\propto R^4$.
• Small narrowings cause large drops in flow.

Steps

1. A parabolic profile
2. A narrowed artery
3. Double the flow
4. Fastest in the middle
5. How much water?
6. Pushing harder