- All turbulence models are wrong, some are useful! George E. P. Box
- In turbulence modeling is always some empiricism and uncertainty involved
- There is no universal turbulence model
- Each test case is specific, scales and speeds are important
- If not sure which turbulence model to use, choose
    - For each turbulence model the proper initial and boundary conditions have to be specified
- Wall treatment is important
- Wall functions may not work for
   - Generally speaking, wall functions is the approach to use if you are more interested in the mixing in the outer region, rather than the forces on the wall.
- We never know a priori the value.
- value is different for compressible and incompressible flows
- Always use the default model constants unless you know what are you doing or you are confident that you have better values.
- Turbulence modeling effect on results is often overestimated!
- Turbulence effect may be higher in external aerodynamics, than in internal aerodynamics.
- There are many cases, where the turbulence model has very small effect on results
- Beginners should concentrate more on fluid mechanics (BTW: 80% of all errors are caused by wrong boundary conditions of pressure and velocity).
- The results matters! Sometimes the results go against the turbulence theory.
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