13.6.2. Apparent Wall Concept

Try these first

1. 1.

   What is the definition of displacement thickness?

   Hint

   Think about how a boundary layer affects streamlines.

2. 2.

   How does momentum thickness differ from displacement thickness?

   Hint

   Consider what each thickness represents in terms of flow characteristics.

3. 3.

   What does displacement thickness quantify in fluid flow?

   • Frictional resistance
   • Mass flow rate reduction
   • Velocity gradient

   Hint

   Consider what happens at surfaces where fluids interact.

4. 4.

   True or False: Momentum thickness and displacement thickness are similar in their definitions.

   • True
   • False

   Hint

   Think of what each thickness represents.

5. 5.

   A fluid flows over a plate with a known displacement thickness of 3 mm. If the free stream velocity is 10 m/s, calculate the mass flow rate reduction due to this thickness over a 1 m section of the plate.

   Hint

   Think about applying the continuity equation with adjustments based on displacement.

6. 6.

   In a turbulent flow scenario, the momentum thickness is determined to be 2 cm. If the total drag experienced by a surface area of 0.5 m² is 30 N, estimate the friction coefficient based on the momentum thickness.

   Hint

   Investigate standard drag equations like F = C * A * ρ * V².