[Dawood Al-Mosuli]

Hello,
I have fluidization problem with two different types of solid particles. I need to represent the drag coefficient for the interaction between the liquid phase and each of the solids using UDF instead of provided default correlations.

1-Should I provide 2 UDF to represent the drag interaction between liquid phase and each type of solids? (UDF for each case separately)? Or one common UDF is enough to represent both?

2-Should I compile or interpret the UDF. I notice that I can't interpret more than one UDF for the interaction.

3-Should I provide the particle diameter inside the UDF or it will be transferred from the main program?
I am asking about this because I notice that there is a given value [diam2 3.e-4] in UDF example 1-custom drag law in the UDF manual.

Thank you