[Daniel_Khazaei]

Hello guys

I'm simulating free surface flow around a ship with air and water!
I've search the forum to get information about choosing turbulence model and wall functions, and learned a lot...

However, in my case the flow around the ship consist of water and air and the y plus value ranges between 1.25 in the air region to 124 in the water region...

How can I keep the y plus above 30 as suggested by fluent guide?
Can I use Scalable wall function in this case?

I have tried to get y plus around 1 to use SST k-omega model, but the mesh quality decreased drastically...


best wishes
tnx in advance

[nvarma]

> How can I keep the y plus above 30 as suggested by fluent guide?

By coarsening the mesh. This tool will help you determine how coarse: http://www.cfd-online.com/Tools/yplus.php

>I have tried to get y plus around 1 to use SST k-omega model, but the mesh quality decreased drastically

This is not clear. How can a turbulence model change your mesh?

[Daniel_Khazaei]

Originally Posted by nvarma

> How can I keep the y plus above 30 as suggested by fluent guide?

By coarsening the mesh. This tool will help you determine how coarse: http://www.cfd-online.com/Tools/yplus.php

tnx for the answer mate
As I said the y plus variation is on the same wall (ship hull)! if I coarsen the mesh the minimum yplus increases but at the same time the maximum yplus surpass 300 limitation...

Originally Posted by nvarma

>I have tried to get y plus around 1 to use SST k-omega model, but the mesh quality decreased drastically

This is not clear. How can a turbulence model change your mesh?

I may have been unclear here
I have refined the mesh to get yplus around 1 but so I can use SST k-omega model! however refining the boundary (inflation layer) decreases the mesh quality...

[nvarma]

that seems like a meshing related issue. May be you can create a near boundary mapped region manually instead of inflation layer so that you have more control.