Learning Forum

[Yannik Danner]

Hello,

i have a hopefully simple question for using UDF.
I try to implement a new coalescence kernel for PBM.
This contains the turbulent energy dissipation rate epsilon.
I am using:

eps = C_D(cell, tm);

turbulence model is RNG k-epsilon.

I get a SIGSEGV
The fl process could not be started.

I know its about epsilon because error does not occur when using eps = const.
what do i have to consider?
Thank you.

[Rob]

https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v231/en/flu_ug/flu_ug_models_popbal.html%23x1-520006.2.1   Which multiphase turbulence option is picked (mixture, by phase)?

[Yannik Danner]

I am using the "dispersed" option

[Yannik Danner]

Update: I tried using:

eps = C_D(cell, tp);

with Thread *tp as primary liquid phase.

No error occurs.(because "dispersed" option only uses primary phase dissipation rate)

Theory Guide for Prince&Blanch Aggregation Kernel says it is using dissipation rate for liquid phase as well.

Is this approach appropriate?

[Rob]

Probably, bear in mind as you change the turbulence option that it may alter where the C_D data is kept. Mixture and Dispersed probably retain the mixture level but per phase may not.