[shereez234]

Consider me a newbie in OpenFoam.

I understand OpenFoam gives pretty good convergence on nice meshes with low skewness and low aspect ratio. But we cannot avoid skewed meshes when the geometry gets more complicatied and when we have O grid Face Cuts. Nether can we always have low aspect ratio hexa/prism cells in the boundar layer due to not enough CPU power or other reasons

In this case. What are the schemes that are suggested? Do they differ when we move from steady state solvers to unsteady solvers?

I am using Limiters for gradients every where 1) the gradient scheme CellLimited leastSquares 1 for both Pressure and Velocity gradients. The velocity Field converges easily when the divergence term of Phi,U is set to limitedLinear 1.

Interpolation Scheme: default linear ,
SnGradscheme: Corrected
and Laplcian terms Gauss linear Corrected.

My questions are:

1) What is the ideal settings for the best Convergence of Pressure equation when you have a skewed mesh ( Max Skewness > 70)

2) Does the choice of Solver PCG or GAMG effect the solution? I always found recommendation to use GAMG but PCG is giving better convergence in my case.