1.1. Comparison with DNS

Try these first

1. 1.

   What is the primary advantage of Direct Numerical Simulation?

   Hint

   Think about the reason why more computations might be necessary.

2. 2.

   What do large eddies extract energy from?

   Hint

   Consider which aspect of the flow provides energy.

3. 3.

   What is the main focus of Direct Numerical Simulation (DNS)?

   • Capturing small eddies
   • High accuracy and resolution
   • Energy extraction from mean flow

   Hint

   Think about what DNS stands for.

4. 4.

   True or False: Large Eddies are isotropic.

   • True
   • False

   Hint

   Recall the definition of anisotropic behavior.

5. 5.

   Explain how the choice of grid size in LES could impact the accuracy of simulations. What considerations must be taken into account?

   Hint

   Think about what happens if the grid is too large or too small.

6. 6.

   Discuss the role of turbulence models in LES. Why can't smaller eddies be resolved directly, and what complications could arise?

   Hint

   Consider the trade-offs between computational demands and accuracy in modeling scales.