3.3. Regions of Turbulent Flow

Try these first

1. 1.

   What is the viscous sublayer?

   Hint

   Think about where viscosity plays the biggest role.

2. 2.

   Name one characteristic of the turbulent layer.

   Hint

   Consider which effects are stronger in turbulent conditions.

3. 3.

   What is the primary characteristic of turbulent flow?

   • Linear flow
   • Chaotic flow
   • Steady flow

   Hint

   Recall the definition of turbulent flow.

4. 4.

   True or False: In the viscous sublayer, turbulent effects dominate.

   • True
   • False

   Hint

   Consider which effects are greater in that layer.

5. 5.

   A cylindrical pipe has an inner diameter of 20 cm and carries water at a velocity of 5 m/s. Calculate the shear stress at the wall and identify whether the boundary is rough or smooth given the height of surface irregularities is 0.2 mm.

   Hint

   Memory aids can assist in relating the mathematical aspects to physical properties of the flow.

6. 6.

   A fluid with a viscosity of 0.002 Pa·s is flowing over a material with k = 0.3 mm. If delta dash is 0.1 mm, determine if the flow is turbulent and the nature of the boundary.

   Hint

   Use the ratios discussed to identify boundary types.