1.4. Boussinesq’s Model

Try these first

1. 1.

   What is shear stress?

   Hint

   Think about how force interacts with surfaces.

2. 2.

   What does eddy viscosity represent?

   Hint

   Consider how turbulence affects fluid movement.

3. 3.

   What is the main difference in shear stress between laminar and turbulent flow?

   • Only viscosity in laminar
   • Only turbulence in turbulent
   • Both factors in turbulent

   Hint

   Think about the components contributing to shear.

4. 4.

   True or False: Eddy viscosity is a fluid property that remains constant regardless of flow conditions.

   • True
   • False

   Hint

   Consider how flow dynamics change near surfaces.

5. 5.

   A fluid with a density of 1000 kg/m³ flows with a turbulent velocity gradient of 0.05 s⁻¹. Determine the turbulent shear stress using a known eddy viscosity of 0.0005 m²/s.

   Hint

   Remember to apply density and velocity gradient in the right formula.

6. 6.

   Explain how Prandtl's mixing length theory aids effectiveness in predicting shear stress in a turbulent flow scenario like a river with varying depths.

   Hint

   Analyze how mixing length changes with depth.