Learning Forum

[SageArt]

I am running CFD analysis on Fluent and I am getting a fatal error from the compute processes. This error comes up when I hook a UDF to define the viscous resistance and porosity inside my computational cells. I have attached snippets of the UDF and the error below. Kindly assist on the possible cause of the problem and how to resolve it.

[Amine Ben Hadj Ali]

We do not debug codes but can you check if you have defined the Cell Memories in Fluent? Does it run without the UDF? What about just using Fluent Expressions instead of UDF's?
Moreover the way you are access the UDS values is wrong: you need to do that inside the cell loop.

[SageArt]

I didn't submit my full code but I did define cell memories and the case works just fine when I am only having porosity. However when I add viscous resistance it gives me that cortex error. I am open to trying out fluent expressions, please link me to a resource that I can refer to for those.
Moreover please elaborate on the last point you raised, I don't get it.

[Rob]

Expressions are covered in the User's Guide, and that also includes examples.
Re the second point, look at how you're using thrm, it should be in the cell loop as it's defined for each cell.

[SageArt]

thrm is properly defined in part of the UDF that I didn't include above.
However, I used an expression to define my porous resistance and kept the rest of the UDF and the simulation now runs without the cortex error. Moreover, I am going to try and parallelize the UDF and see if it also gets rid of the cortex error.

[Rob]

But look at it's usage in the part you shared: it's not a single value.

[SageArt]

At the moment, it is just initialized and not used anywhere on that code. Initially, I used it in the cell loop and later replaced it with the user defined memory. I will remove it from those lines of code to leave everything neat.