Flag to stop using UDF in a defined zone

Bibill · May 18, 2021, 06:00

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, 21:40

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, 11:35

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, 06:00	Flag to stop using UDF in a defined zone	#1
Bibill New Member Join Date: May 2020 Posts: 23 Rep Power: 6	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, 21:40		#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

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
cell zone creation for degassing udf implementation	shahjehan	Fluent UDF and Scheme Programming	0	August 3, 2016 12:30
Error in solution using "Grid Interface"	agustinvo	FLUENT	4	January 20, 2015 13:03
Possible Bug in pimpleFoam (or createPatch) (or fluent3DMeshToFoam)	cfdonline2mohsen	OpenFOAM	3	October 21, 2013 10:28
How to stop diffusion and advection in a zone for selected species.	hda	FLUENT	0	March 19, 2012 00:59
OpenFOAM static build on Cray XT5	asaijo	OpenFOAM Installation	9	April 6, 2011 13:21

May 20, 2021, 11:35		#3
Bibill New Member Join Date: May 2020 Posts: 23 Rep Power: 6	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