13.7. Turbulent Boundary Layers

Try these first

1. 1.

   What is a turbulent boundary layer?

   Hint

   Think about how water flows differently over smooth versus rough surfaces.

2. 2.

   Describe displacement thickness.

   Hint

   Consider the effect of slow flow near a surface.

3. 3.

   Which of the following describes turbulent boundary layers?

   • A. Smooth and consistent flow
   • B. Chaotic and fluctuating flow
   • C. Completely laminar

   Hint

   Consider how a turbulent river flows compared to a calm lake.

4. 4.

   True or False: Displacement thickness is the distance that streamlines are deflected due to boundary layer effects.

   • True
   • False

   Hint

   Reflect on how boundary layers influence flow patterns.

5. 5.

   Consider a flat plate in a flow with a speed of 5 m/s. Using the one-seventh power law, calculate the velocity at a point 0.02m within the turbulent boundary layer.

   Hint

   You may need to determine the boundary layer thickness first based on flow conditions.

6. 6.

   Evaluate how the presence of a turbulent boundary layer affects the drag force on a large aircraft wing in cruise conditions.

   Hint

   Review how turbulent layers generate drag compared to laminar layers.