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bearcat February 14, 2010 21:40

Some confusion about coupled solver for incompressible flow

I am working on the coding of a coupled solver for steady-state incompressible flow (pressure-based). I want to strengthen myself the background theory before doing programming. It is hard to find a complete and systematic tutorial (CFD books for engineers) on this, except some math papers.

Here are some questions:

1. What's the difference between a strongly coupled and a weak(or regular) coupled? Does the "strongly coupled" also mean strongly implicit? Any example paper?

2. Is the use of artificial-compressibility taken as a coupled way? I think it's welcomed in some papers but not in commercial codes. Is it right?

3. What is a smoother, pre-smoother and post-smoother? is it the same concept with preconditioner?

4. Is multigrid a method or a preconditioner or can be both?

5. I am thinking of a design of the numerics for a wind turbine problem to achieve the best convergence speed:

diagonal Vanka smoother + ILU preconditioner + geometrical multigrid (accelerator)+ BiCGStab (solver)

Is this practical?

6. When I should use a flux-splitting scheme? Is it necessary or just upwind schemes will be sufficient?

7. What kind of velocity-pressure coupling should I use for FVM collated grid? Rhie-Chow interpolation, pseudo-velocity or other method?

8. Should I keep the time-term (hyperbolic) or just solve the steady-state equation (elliptic)?

Can anyone help? Thank you.

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