5.1. Laminar and Turbulent Boundary Layers

Try these first

1. 1.

   What does the no-slip boundary condition imply?

   Hint

   Think about what happens at the edge of a surface.

2. 2.

   Define a boundary layer.

   Hint

   Consider the thickness of fluid layers.

3. 3.

   What is the no-slip condition?

   • Fluid velocity at the surface is zero
   • Fluid accelerates at the surface
   • Fluid has constant velocity everywhere

   Hint

   Consider what happens at solid surfaces.

4. 4.

   True or False: The boundary layer only exists in turbulent flow.

   • True
   • False

   Hint

   Recall the flow types discussed.

5. 5.

   Consider a fluid with a kinematic viscosity of 0.002 m²/s flowing over a plate with a free stream velocity of 3 m/s. If the boundary layer transitions to turbulent flow, at what downstream distance from the leading edge does this transition occur?

   Hint

   Remember to isolate x in your equation.

6. 6.

   How would the flow patterns differ if the same fluid had a much higher viscosity? Discuss the implications on the boundary layer.

   Hint

   Think about the relationship of viscosity to flow stability.