2.1. Effects of Velocity Gradient

Try these first

1. 1.

   What is the boundary layer?

   Hint

   Think about where fluid flows meet solid surfaces.

2. 2.

   What does the Reynolds number indicate?

   Hint

   Consider its role in distinguishing flow types.

3. 3.

   What characterizes the laminar sub-layer?

   • High turbulence
   • Linear velocity profile
   • Unchanging viscosity

   Hint

   Think about the conditions in the layer close to solid boundaries.

4. 4.

   True or False: The Reynolds number only applies to laminar flow.

   • True
   • False

   Hint

   Consider the range of flow behavior it describes.

5. 5.

   A flat plate is subjected to uniform flow. Calculate the shear stress at the laminar sub-layer when the dynamic viscosity is 0.001 Pa·s, and the velocity gradient is 10 s^-1.

   Hint

   Apply the shear stress equation directly with the given values.

6. 6.

   In a hydraulic system, how does understanding boundary layer principles affect the design of a pipe? Discuss the consequences of neglecting them.

   Hint

   Think about the practical applications and possible flow outcomes in real systems.