Theory and Practice association/coupling
 

Hello everyone.
As you can see, I'm new to this forum, and also new to CFD.

I started my quest into CFD only couple months ago, and I started the literature by reading Hirsch's book (Numerical Computation of Internal and External Flow), which is said to be the most informative and is also the main reference for the CFD course in my Master program.
Indeed, this book is very very complete, I guess he states a little about everything. I also bought Versteeg/Malalaskera and Anderson, J.D. books, but didn't read yet.

I've read about consistency and stability (leading to convergence) in Hirsch, and also about diffusion and dispersion errors of lots of schemes, which I personally assume that are the main topics of CFD. But the question is:

How do I couple this theory about stability and errors to my practical problem when using commercial CFD packages?

I'm actually using Fluent but this question goes to any commercial CFD pack. I can't seem to couple things like analyzing amplification factor or eigenvalues spectrum for stability conditions on Courant (CFL) number with an arbitrary mesh or problem before actually computing it in the software. What if I set up something that is not stable? . Also, can't see where the 'phase angle' goes on all of this, as the errors depends on this.

I don't know if I made myself clear but the thing is that I'm trying to couple the theory I read to practical problems to incorporate best practice while having analyzed what's the best scheme for my problem/mesh generated, CFL number, and also knowing the possible diffusion and dispersion errors my problem (physical, mesh and scheme) could generate, and for some reason I can't see a clear bridge between the theory and usage of commercial packages. (Edit: forgot about the so-called limiters for second order schemes to achieve monotonicity and avoid oscillations when discontinuities in the solution appears)

I'd be very very glad if someone could help me on this 'coupling' issue.