5. Displacement Thickness

Try these first

1. 1.

   What does the displacement thickness (δ*) represent?

   Hint

   Think about the value we use to measure where the boundary ends.

2. 2.

   What is the significance of the laminar sub-layer?

   Hint

   Consider the role of viscosity in fluid layers.

3. 3.

   What is the formula for calculating displacement thickness?

   Hint

   Think about the fundamental definitions within boundary layer theory.

4. 4.

   True or False: The laminar sub-layer occurs in both laminar and turbulent flows.

   • True
   • False

   Hint

   Consider where viscosity plays a role in fluid motion.

5. 5.

   A flow has a uniform velocity of 10 m/s over a flat plate. If the boundary layer thickness at a certain part of the plate is 0.05m, calculate the displacement thickness if the velocity at the edge of the boundary layer is measured to be 9.5 m/s.

   Hint

   Consider the boundary flow to find the effective thickness.

6. 6.

   A system has different Reynolds numbers at various sections of the plate—calculate the variation in displacement thickness across these sections and analyze how turbulence might affect fluid behavior.

   Hint

   Relate the Reynolds number to the displacement thickness across the given plate.