Please contribute a question to put on FAQs for CFD wiki at cfd-online. These questions and their solution (if we have) shall be put on cfd-online. I to start with contribute :

Q: What is turbulent viscosity ratio warning and how to deal with it?

Q: How do i carry out rotating body analysis, eg a rotating sphere or cylinder in flow?

Q: How do i get better and faster convergence?

Q: What is the role of under-relaxation parameters? What should be the optimum choice of these parameters?

I would add several commonly-asked questions.

Q: How can I determine the inputs for a porous media or porous jump from flow versus pressure drop data?

Q: How do I model heat conduction in a composite wall?

Q: What pressures should be specified at inlets and outlets for buoyancy flow problems?

Q: Are there any general guidelines on selecting a turbulence model?

Q: How can both turbulent and laminar flow be included in one model?