How to set turbulent model constants in a journal file?

xq712000 · April 18, 2019, 03:44

Dear All,

I want to change the model constants such as C1, C2, and Prandtl Number
in k-espilon turbulent models

How can I do this in a journal file ?

LuckyTran · April 18, 2019, 13:30

I found the TUI macros to set these to user-defined-functions in the expert settings, but this is probably too complex a solution. I couldn't find the TUI macros for setting these parameters directly like you can in the GUI. But you can still use rpstvar if you know the fluent built-in variable names. Unfortunately you didn't say which k-epsilon model you use and precisely which parameters you want to change for me to give a comlete answer... But here are some examples:

standard k-epsilon

Code:

(rpsetvar 'kecmu 0.09)
(rpsetvar 'ke1 1.44)
(rpsetvar 'kec2 1.92)
(rpsetvar 'kesigk 1)
(rpsetvar 'kesige 1.3)

realizable k-epsilon

Code:

(rpsetvar 'rke-kec2 1.9)
(rpsetvar 'kesigk 1)
(rpsetvar 'rke-kesige 1.2)
(rpsetvar 'prt 0.85)
 (rpsetvar 'wallprt 0.85)

Open the .cas file (saved as ascii) in with a text editor and you can figure out what these variable names are.

xq712000 · April 19, 2019, 02:38

Thank you very much! This is most helpful! ^_^

April 18, 2019, 03:44	How to set turbulent model constants in a journal file?	#1
xq712000 New Member XieQing Join Date: Mar 2013 Location: Capital of Qin Dynasty Posts: 22 Rep Power: 13	Dear All, I want to change the model constants such as C1, C2, and Prandtl Number in k-espilon turbulent models How can I do this in a journal file ?

April 18, 2019, 13:30		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	I found the TUI macros to set these to user-defined-functions in the expert settings, but this is probably too complex a solution. I couldn't find the TUI macros for setting these parameters directly like you can in the GUI. But you can still use rpstvar if you know the fluent built-in variable names. Unfortunately you didn't say which k-epsilon model you use and precisely which parameters you want to change for me to give a comlete answer... But here are some examples: standard k-epsilon Code: (rpsetvar 'kecmu 0.09) (rpsetvar 'ke1 1.44) (rpsetvar 'kec2 1.92) (rpsetvar 'kesigk 1) (rpsetvar 'kesige 1.3) realizable k-epsilon Code: (rpsetvar 'rke-kec2 1.9) (rpsetvar 'kesigk 1) (rpsetvar 'rke-kesige 1.2) (rpsetvar 'prt 0.85) (rpsetvar 'wallprt 0.85) Open the .cas file (saved as ascii) in with a text editor and you can figure out what these variable names are. xq712000 and lisa_china like this.

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April 19, 2019, 02:38		#3
xq712000 New Member XieQing Join Date: Mar 2013 Location: Capital of Qin Dynasty Posts: 22 Rep Power: 13	Thank you very much! This is most helpful! ^_^