2.6. Eddy Viscosity and Kinetic Energy

Try these first

1. 1.

   What is Reynolds shear stress?

   Hint

   Think about how turbulence affects flow velocity.

2. 2.

   What does turbulent kinetic energy represent?

   Hint

   Consider both mean and fluctuating velocities.

3. 3.

   What does Reynolds shear stress measure?

   • Inertial forces
   • Momentum transfer
   • Viscous forces

   Hint

   Consider how turbulence affects movement.

4. 4.

   The k-epsilon model is primarily focused on which aspect?

   • True
   • False

   Hint

   Remember what k and epsilon stand for.

5. 5.

   Assuming a flow has a turbulent kinetic energy of 0.5 m²/s² and a dissipation rate of 0.1 m²/s³, calculate the eddy viscosity. What implications does the result have for modeling this flow?

   Hint

   Remember to identify and separate each variable in the formula.

6. 6.

   Discuss how you would approach modeling a high Reynolds number flow using the k-epsilon model. What additional factors would you need to consider for computation?

   Hint

   Consider the dimensions of the simulation grid compared to the Kolmogorov scale.