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Transport mesh from ICEM CFD, to Fluent, to Sysnoise

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Old   March 22, 2010, 07:15
Default Transport mesh from ICEM CFD, to Fluent, to Sysnoise
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Wieland De Lepeleire
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For a master-thesis I would like to export some CFD results (more exactly: surface pressure distribution on a side view mirror) from Fluent to LMS Sysnoise. This already succesfully worked with a test case.

I'm now facing the following problem: I would like to refine the mesh, since CFD results were in accordance with other papers for low frequencies only. Therefore I refined the zone after the mirror in ICEM CFD, but when checking the mesh in ICEM an error of uncovered faces occured. There are two options: ignore the error (as proposed by Simon on this thread), or fix the error.

When ignoring the error, the mesh (figure 1) can be succesfully imported in Fluent and realistic results are calculated. The problem is that it's impossible to export the mesh in Nastran format (which is necessary for Sysnoise). You can see this in figure 2. Only ASCII, EnSight Case Gold, and Fieldview Unstructured file formats are possible.

When I fix the error in ICEM, the uncovered faces are covered and I add these faces to the "body"-part. The mesh can be imported in Fluent (figure 3) and it's possible to export them in Nastran-format (figure 4). But the new faces cause problems in Fluent since I can not prescribe an "interior" boundary condition for this surface... So calculations are not possible.

The Fluent manual learned me: "ANSYS FLUENT supports exporting polyhedral data only for ASCII, EnSight Case Gold, and Fieldview Unstructured file formats. For further details, see Sections 4.14.4, 4.14.9, and 4.14.12."
So I need to work around the polyhedral data problem. Anyone experience with this? Or does somebody knows how to export the mesh from Fluent in another way?
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File Type: jpg Refinement_NotFixed.jpg (95.6 KB, 55 views)
File Type: jpg Export_NotFixed.jpg (35.0 KB, 43 views)
File Type: jpg Refinement_Fixed.jpg (97.1 KB, 47 views)
File Type: jpg Export_Fixed.jpg (35.9 KB, 30 views)
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Old   March 29, 2010, 08:29
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Hi
Wieland

Looks like you are trying to export the pressure data from the wake region of the mirror.

If i have perceived it right the interior surface can be separated in Tgrid before you run the Fluent flow analysis.

And then i feel you could import pressure data on this interior surface into sysnoise.

Uday
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Old   April 15, 2012, 06:28
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Mohammad.R.Shetab
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Dear Wieland

I have a question!! I'm trying to couple Ansys Fluent with Sysnoise to do some aeroacoustic calculation, but since now I have no success. Here is the procedure:

1- Running the calculations with Fluent and it makes the files .index and .asd. When I save the data, It also creats a .dat file (not .data file which is mentioned as a requisit for sysnoise). I also export the mesh in Nastran format and a .bdf mesh file is created.

2- I imported the .bdf mesh file into sysnoise using File>Import>Mesh>Nastran Format

3- I also tried to import Surface distributed Dipoles using Model>Sources>Surface Distributed Dipoles

- I choose the mesh as the surfaces where the sources will be generated by typing All in selector.
- I choose the data type Time and the frequency 100, and in front of File name I choose the .index file with format of Fluent.
- In the next step, I choose Use Other Mesh and select the .dat file with fluent format.
- The interpolation algorithm will remain unchanged as : interpolation algorithm number: 1 Number of Nodes in interpolation: 6

When I click finish this error will occur:

Error *** This is not a Fluent Format File

Cannot read Structural Mesh File :.....

Questions:
1- What is this error? what is wrong?
2- My mesh is triangular, Is something wrong with this kind of mesh?
3- Is .dat file is different from .data file? if it is, How can I produce .data file with fluent? (In sysnoise tutorial it is said that in this step a .data file should be used as the mesh parameter)

Thank you,
Mohammad Reza Shetab
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