11.1.2. Wall Shear Stress Calculation

Try these first

1. 1.

   What is wall shear stress?

   Hint

   Consider the interaction between fluid and a stationary boundary.

2. 2.

   Name one assumption when using Navier-Stokes equations.

   Hint

   Think about conditions under which fluid flow is analyzed.

3. 3.

   What does wall shear stress depend on?

   • Density of fluid
   • Velocity gradient
   • Temperature of fluid

   Hint

   Think about how the fluid's flow characteristics affect stress.

4. 4.

   True or False: Vorticity can be zero for all flow types.

   • True
   • False

   Hint

   Recall the definition of vorticity in fluid mechanics.

5. 5.

   Given a fluid with dynamic viscosity μ = 0.001 Pa·s flowing between two plates separated by 0.1 m, with a pressure gradient dp/dx = -50 Pa/m, determine the wall shear stress.

   Hint

   Make sure to correctly apply the relationship between shear stress and viscosity with the velocity gradient.

6. 6.

   Discuss how the average velocity changes in the transition from laminar to turbulent flow in a channel.

   Hint

   Think about how eddies in turbulent flow impact the speed of fluid at different depths.