Flag to stop using UDF in a defined zone

Bibill · May 18, 2021, 05:00

Dear all,

Is It possible in Fluent to include a flag/domain check to apply the UDF only if a condition is fulfilled and then make the change more specific ?

For instance, if I use a DEFINE_TURBULENT_VISCOSITY in a Stress-Blended Eddy Simulation, can I only use this UDF to modify the turbulent viscosity for the RANS part and not the LES one (without hardcoding a subgrid scale viscosity model with a if{..}else{...} statement) ?

Thanks !

AlexanderZ · May 19, 2021, 20:40

how are you going to use condition statement without if{..}else{...} ?

using journal file (or scheme) you may turn on/off sources (as as you would do it manually in GUI) may be this is a way out for you

Bibill · May 20, 2021, 10:35

What I meant by no if{...}else{...} was to not hardcoding the turbulent viscosity (sub grid scale) model for the LES but rather something like :

IF(condition fulfilled){use DEFINE_TURBULENT_VISCOSITY}
ELSE{do not use DEFINE_TURBULENT_VISCOSITY}

I'll have a look to scheme

Thanks

May 18, 2021, 05:00	Flag to stop using UDF in a defined zone	#1
Bibill New Member Join Date: May 2020 Posts: 23 Rep Power: 5	Dear all, Is It possible in Fluent to include a flag/domain check to apply the UDF only if a condition is fulfilled and then make the change more specific ? For instance, if I use a DEFINE_TURBULENT_VISCOSITY in a Stress-Blended Eddy Simulation, can I only use this UDF to modify the turbulent viscosity for the RANS part and not the LES one (without hardcoding a subgrid scale viscosity model with a if{..}else{...} statement) ? Thanks !

May 19, 2021, 20:40		#2
AlexanderZ Senior Member Alexander Join Date: Apr 2013 Posts: 2,363 Rep Power: 34	how are you going to use condition statement without if{..}else{...} ? using journal file (or scheme) you may turn on/off sources (as as you would do it manually in GUI) may be this is a way out for you __________________ best regards ****************************** press LIKE if this message was helpful

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May 20, 2021, 10:35		#3
Bibill New Member Join Date: May 2020 Posts: 23 Rep Power: 5	What I meant by no if{...}else{...} was to not hardcoding the turbulent viscosity (sub grid scale) model for the LES but rather something like : IF(condition fulfilled){use DEFINE_TURBULENT_VISCOSITY} ELSE{do not use DEFINE_TURBULENT_VISCOSITY} I'll have a look to scheme Thanks