[Mohsin1]

When I export OpenFOAM results to Fluent using FoamDataToFluent, the pressure contours don’t match those in ParaView, even for a standard case like the elbow benchmark. Why does this discrepancy occur, and how can I ensure consistent pressure visualization between the two?

[JBeilke]

How different are they? Can you post 2 pictures? During the export we might have to choose between cell based values and vertex/node based values.

[Mohsin1]

Originally Posted by JBeilke

How different are they? Can you post 2 pictures? During the export we might have to choose between cell based values and vertex/node based values.

I have attached the pictures as well as the case. Velocity contours are exactly same. But pressure are not. The pressure p (which i think is kinametic pressure in openfoam) when opened in paraview does not match with any of the pressure (static pressure, dynamic pressure, total pressure etc) in fluent. How can I ensure consistent pressure visualization between the two (paraview and fluent, just like velocity contours)?

[JBeilke]

Your fluent pressure is zero everywhere. So something went wrong.


The pressure for incompressible cases in OpenFOAM is p/rho and not the pressure itself.

[Mohsin1]

Originally Posted by JBeilke

Your fluent pressure is zero everywhere. So something went wrong.


The pressure for incompressible cases in OpenFOAM is p/rho and not the pressure itself.

Yes static pressure is zero in fluent. I don't know how foamDataToFluent converts the p/rho to pressure in fluent. Is there a way to see the static pressure or p/rho in fluent?

[JBeilke]

What's your boundary type for "frontAndBackPlanes" in Fluent. You should specify it as symmetry or slip-wall. When you define it as pressureOutlet, your resulting pressure will be zero.

[Mohsin1]

Originally Posted by JBeilke

What's your boundary type for "frontAndBackPlanes" in Fluent. You should specify it as symmetry or slip-wall. When you define it as pressureOutlet, your resulting pressure will be zero.

Setup:

I'm using the standard elbow tutorial case from OpenFOAM without any modifications.

My goal is to verify if foamDataToFluent correctly exports the mesh and data for CFD results comparison in Fluent (for another simulation).

Problem:

The frontAndBackPlanes boundary in OpenFOAM is defined as type empty, but when exported to Fluent, it appears as a pressureOutlet.

Attempted Fixes:

1. Manually changing it to symmetry in Fluent did not resolve the issue.

2. Modified the OpenFOAM boundary files (p, U, and boundary) to set frontAndBackPlanes as symmetry, then re-exported using foamMeshToFluent and foamDataToFluent.

Result: Fluent now correctly recognizes it as symmetry, but the static pressure remains zero.

Request:

Could you please review the attached ZIP file from my previous replies and help identify the issue? Any guidance would be greatly appreciated.

[JBeilke]

I already read your elbow.msh into StarCCM+ and found that frontAndBack are defined as pressure-outlet. Thats why I suspected something wrong there.

So your problem is the Fluent setup and has nothing to do with OpenFOAM or with the postprocessing.

It should be easy to change the boundary type within FLUENT. There is no need to change the mesh in OF and do a reexport.

Please check within Fluent, if there is a "pressure" variable. Usually you have "pressure" , "absolute-pressure" ...

[Mohsin1]

Originally Posted by JBeilke

I already read your elbow.msh into StarCCM+ and found that frontAndBack are defined as pressure-outlet. Thats why I suspected something wrong there.

So your problem is the Fluent setup and has nothing to do with OpenFOAM or with the postprocessing.

It should be easy to change the boundary type within FLUENT. There is no need to change the mesh in OF and do a reexport.

Please check within Fluent, if there is a "pressure" variable. Usually you have "pressure" , "absolute-pressure" ...

Even after modifying the boundary type in Fluent, the issue of zero static pressure remains unresolved. Although Fluent offers various pressure types, none of them match the pressure values observed in ParaView (OpenFOAM) or correspond to a multiple of the fluid density (ρ).