Learning Forum

[r.kliza]

Hi 

I have a problem with compiling UDF file in fluent 13.0. I imported the 2D computational mesh of my model in .nas format from COMSOL. I loaded it into Fluent. I then tried to compile the UDF with a sequence: Define>User-defined>funtcions>compiled. I then loaded the required file with the .c extension, clicked Build and then Load and this message appears: 

The UDF library you are trying to load (C:\Program Files (x86)\Elektroaero\Comsol-Fluent\libudf) is not compiled for 2ddp on the curent platform (win64). The system cannot find the specified path. C:\Program Files (x86)\Elektroaero\Comsol-Fluent\C:\Program Files (x86)\Elektroaero\Comsol-Fluent\libudf\win64\2ddp\libudf.dll. 

Anyone have an idea how to solve this problem. 

Kind regards

Rafał

[Rob]

I'm not even sure v13 was compiled for 64bit, please can you check the install? From memory, v13 is from about 2008 so you may want to update. 

[r.kliza]

Thanks Rob. Im tried to build my model again in Fluent 2023 but there is another problem. This time I cant even load my mesh in NASTRAN file (.nas) into my case. Mesh becomes from COMSOL Multiphysics and during loading mesh appears this error: "

Cleanup script file is C:\Users\superkomp2\Desktop\Elektroaero\Comsol-Fluent\cleanup-fluent-superkomp2-22100.bat

Reading "C:/Users/superkomp2/Desktop/Elektroaero/Comsol-Fluent/Mesh.nas"...

Warning: no nodes readanalyzing boundary connectivity...done.

Meshing> Reading "| utility fe2ram -tNASTRAN -s -d3 C:/Users/superkomp2/Desktop/Elektroaero/Comsol-Fluent/Mesh.nas"...

Warning: no nodes readanalyzing boundary connectivity...done." 

So this is error with import a .nas mesh file to Fluent but I dont understand what Im doing wrong. 

Best regards 

Rafał

 

 

[Rob]

Try reading the mesh into Fluent Meshing and see what comes in. 

 

[r.kliza]

Hi ROB 

Thank you for your reply. Import of mesh in nastran file from comsol to fluent 2023 was successful. However, in version 2023, the UDF file completion problem is still the same as in version 13.0 - fluent cannot find the 2ddp libudf.dll library in the selected directory. Strange. How can I solve this problem?  

 

 

 

[Rob]

 

You need to compile the UDF. Open Fluent in 2d dp and compile the .c file (use the built in compiler) and look for errors. Assuming it works, read in the case/mesh you’ve already got working. 

Edit. Check the UDF macros in the newer documentation as a few calls have changed over the years to simplify and/or extend functionality. 

 

[r.kliza]

 

Hi Rob. The problem with compling UDF file is solved. But I have another problem. After hybrid initialization of my case appears this message: 

Node 1: Process 16788: Received signal SIGSEGV.

 

==============================================================================

 

===================================================================================

= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES

= RANK 0 PID 6924 RUNNING AT superkomp

= EXIT STATUS: -1073741819 (c0000005)

===================================================================================

 

===================================================================================

= BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES

= RANK 1 PID 16788 RUNNING AT superkomp

= EXIT STATUS: -1073741819 (c0000005)

===================================================================================

The fl process could not be started. 

What means f1 process?

 

 

 

[Rob]

It's "fl" or "FL" so means the Fluent process. SIGSEV typically means you've got a problem with data somewhere: Fluent needs something and it's not available. Now the UDF compiles you may need to focus on what data it requires and what data is supplied to Fluent. 

[r.kliza]

Rob, thanks for another answer. Could you tell me please where I should searching for error? I understood that .udf file could consist some kind of mistake in code? I haven`t any idea where I should start searching for error. Maybe more precisly, how to find what kind of data are required for Fluent and which data are missing?

[Rob]

If the code compiles then it's "good". However, you may be returning a nonsensical number to the solver. If you alter the UDF to put it's output to a UDM rather than the code what is it doing? Or change a UDF variable output to a constant to check what's going on. Trouble shooting is pretty much a case of turning things off until it works and then turn it back on until it breaks.