Learning Forum

[ham]

I wrote some new UDF's to give Fluent more accurate dynamical viscosity and thermal conductivity values for Hydrogen. Previously I had a more basic UDF just giving data for 1atm, now I am providing data for a large range of pressures and temperatures. The UDF reads in data taken from a NASA CEA simulation using a .csv file. The UDF checks the pressure from fluent, then fills a temporary array of the corresponding conductivity values. Then the UDF checks the temperature from fluent and linearly interpolates the conductivity from that temporary array.

When attempting to initialize the simulation with the new UDF's compiled, Fluent crashes almost instantly and doesn't give any error message. Clearly it's the new UDF's causing the crash, but I don't know why. The only meaningful change to the old udf's is this one reads in a .csv file. Any ideas for why this causes a crash?

I would like to give the code here but it exceeds the max character count.

[Rob]

You are allowed to add things over a couple of posts. We only complain when it's to bump a thread!
Assuming the initialisation completes plot the material properties to make sure they're sensible. You may also find it's safer to run an iteration with fixed properties then use the UDF. The latter means all of the flow gradients etc are present in case your code uses them.