1.6. Reynolds Shear Stress

Try these first

1. 1.

   Define shear stress.

   Hint

   Think about forces and areas.

2. 2.

   What does eddy viscosity represent?

   Hint

   Consider how turbulence creates additional resistance.

3. 3.

   What is the formula for Reynolds shear stress?

   • -ρ⟨u'v'⟩
   • -ρ⟨u'v'⟩²
   • ρ⟨u'v'⟩

   Hint

   Look for the expression involving the average products of fluctuating components.

4. 4.

   Eddy viscosity is independent of the flow's conditions. (True/False)

   • True
   • False

   Hint

   Consider how turbulence affects the fluid's behavior.

5. 5.

   Calculate the Reynolds shear stress for a flow with velocity fluctuations u' = 0.1 m/s and v' = 0.05 m/s, given density 1000 kg/m³.

   Hint

   Apply the Reynolds formula and don't forget to handle signs.

6. 6.

   Explain how increasing turbulent flow impacts viscous shear stress across the pipe's radius in a given scenario.

   Hint

   Think about flow profiles in turbulent conditions.