19.7.2. Implications of Roughness on Friction Factors

Try these first

1. 1.

   What defines the Reynolds number?

   Hint

   Think about the balance between two types of fluid forces.

2. 2.

   What is the formula for friction factor in laminar flow?

   Hint

   Recall the formula specifically for laminar flow.

3. 3.

   What is the critical Reynolds number for turbulent flow?

   • 2300
   • 4000
   • 10000

   Hint

   Think about the boundary between laminar and turbulent flow.

4. 4.

   Is a higher surface roughness level likely to increase energy losses?

   • True
   • False

   Hint

   Reflect on how surface interactions affect fluid movement.

5. 5.

   A water pipe with a diameter of 0.1 m has a roughness height of 0.002 m. If the fluid has a Reynolds number of 5000, calculate the friction factor.

   Hint

   Recall how to utilize Moody's chart, or use formulas for turbulent flow.

6. 6.

   Compare the energy losses of a smooth vs. a rough pipe over the same length and flow rate. Explain the implications for engineering design.

   Hint

   Think about how different characteristics will influence the flow dynamics.