Premixed source UDF
 

Hi

Has anyone ever tried using the define_premixed_source UDF provided in the ansys udf guide? I can it get it work and have modified it to do what I need it to but in trying to get to the bottom of why the results are terrible I have discovered that the turbulent flame speed is a constant value across the whole mesh. A number of the terms in the turbulent flame speed definition certainly vary across the mesh - turbulent dissipation rate for example.

I am a little confused but I can only assume that it is taking some kind of average value across the whole mesh at the start of the run (steady state so no time step element). I thought you didn't need to include the 'thread loop' part which would typically tell the UDF to look at the node values as Ansys did that for you.

Has anyone else come across this?

Many thanks