1.3. Shear Stress in Turbulent Flow

Try these first

1. 1.

   What is shear stress?

   Hint

   Think about the forces acting along plane surfaces.

2. 2.

   Define eddy viscosity.

   Hint

   It relates to turbulent characteristics of the fluid.

3. 3.

   Which of the following best describes shear stress in turbulent flow?

   • Only from viscosity
   • Combines viscosity and turbulence
   • Only from turbulence

   Hint

   Think of the definitions you've learned about flow types.

4. 4.

   Eddy viscosity is a fluid property.

   • True
   • False

   Hint

   Consider what makes different viscosities function differently.

5. 5.

   A fluid with a dynamic viscosity of 0.001 Pascal seconds flows through a pipe. If the average velocity is 3 m/s and the distance from the wall is 0.1 m, compute the approximate turbulent shear stress if the mixing length is estimated at 0.4y.

   Hint

   You'll need to establish the gradient from the known velocity and distance.

6. 6.

   Design a study method to determine how changes in turbulence affect shear stress in an engineered hydraulic system. Explain the steps involved.

   Hint

   Think about variables that can be controlled in your design.