[CRI_CFD]

Hi everyone,

I am making bifurcated pipe simulation using k-w SST turbulence model. The flow is assumed to be incompressible and steady. I use two types of BCs for nut, k and omega:

1. wall:

nut: type nutLowReWallFunction
value uniform 1e-6

k: type kQRWallFunction
value uniform 1e-6

omega: type omegaWallFunction
value uniform 400



2. wall:

nut: type fixedValue
value uniform 0

k: type fixedValue
value uniform 0

omega: type zeroGradient


Both are providing a converged solution ( I am not sure if it's grid independent yet).

I am using the same mesh for both, which yields to a yplus_max=4.4

My questions are: Am I resolving well boundary layer? For this yplus value, which set up is better? I understand that if I use k-w SST with wall functions then I should have yplus between 30 and 300, on the other hand if I don't use wall functions then my yplus should be 1 or below.

So taken this into consideration and having on mind that both solutions are converging, have I to expect that the results are innacurate? Or yPlus below 5 is good for using the nutLowReWallFunction? I am highly confused...

The set up for the other patches is shared by both models. The only differences are those related to wall.

And the last one, why can I only compute yPlus when I use wall functions at the wall with yPlusRAS utility? I can be wrong and I am not sure if I am remembering well, but I think that FLUENT allows this computation in all cases when a turbulence model is used...

Hope somebody could help...I am not confident in what I am doing now...

Thanks in advance to all the users!