Hi;

I want to write a UDF to modify turbulent viscosity in two phase region in multiphase cavitating flow. In fluent documentation there is an example for such UDF for Std k-e model. If I want to write this UDF for RNG k-e and multiphase model, what Should I do? In my modification formula there is mixture density and constant density of vapor and water and mixtur k and e. Should I use commands like thread_subthread etc. ?

Thanks

ROOZBEH

There is no significant difference between a UDF written for RNG k-eps and Standard k-eps calculations.

You can read the mixture density value recovering the thread of mixture using specific macros, or just calculating is as a weighted average using as weights volume fractions of phases.

For constant densities of vapour and water, you can use the C macro #define to set them in your UDF, or read them using C_R(cell, phase_thread), where phase_thread is the thread of the phase of which you want the density.

Hope this helps.

Hi

ap

Hi; Thanks for your answer. Can I send you my new UDF corresponding to your suggestion, by e-mail!?

ROOZBEH

Sure.

Hi

ap