13.5. Boundary Conditions and Solutions

Try these first

1. 1.

   What is the definition of a boundary layer?

   Hint

   Think about where water flows over a surface.

2. 2.

   What condition does the no-slip boundary imply at the surface?

   Hint

   Remember that the fluid cannot 'slip' across the surface.

3. 3.

   What does the term 'displacement thickness' refer to?

   • A measure of the flow speed
   • A shift in streamline position
   • Layer depth in the fluid

   Hint

   Think about how streamlines are affected when a boundary layer is present.

4. 4.

   True or False: Laminar flows are characterized by chaotic motions.

   • True
   • False

   Hint

   Recall the definitions of laminar and turbulent flows.

5. 5.

   A fluid flows past a flat plate with a length of 5m. If the free stream velocity is 10 m/s and the kinematic viscosity of the fluid is 0.001 m2/s, calculate the boundary layer thickness at the end of the plate.

   Hint

   Remember to compute Reynolds number first!

6. 6.

   Describe how the transition from laminar to turbulent flow can be experimentally determined, using examples from wind tunnel studies.

   Hint

   Consider what techniques are often used in fluid dynamics experiments.