Hi.

When I in a UDF change the diameter of a single DPM source from say 100 to 1, then the diameter of the particles in the first many cells are 100, and first after approx. 10-15 cells it is changed to 1. I would have thought that the diameter would be changed immediately after 1 cell (I am not changing the initial diameter).

Can anyone please enlighten me.

Cheers Christian

I have tried to change the order in which the DPM laws are called incl. my UFD, and the results are very different. None of the results are however as I expected them to be.

I am wondering: Can it be that Fluent version 6 have problems with running UFD's ? Any experiences ?

Cheers Christian

I have been working with customizing the particle laws in Version 6 with UDFs with the past few months and have not seen any inconsistencies.

However, my experience is that once you start using UDFs for particle laws, your code will have to take account of everything - particle diameter, mass, density, temperature, composition, source terms etc.

You may well have to modify the DPM_switch UDF as well to transition from one law to another.

Also, be careful about setting initial particle conditions in the material panels.

Thank you for your advice, Allan.

Maybe my problem is with the density. I will try to be careful in defining and modifying parameters.

Do you know how to terminate a law (for example the boiling law) from the UDF.