[vinerm]

Are you using double quotes around the command? The command needs to have bracket around it but no double quotes.

Secondly, contours of species mass fraction will always exist if species transport is enabled. What I suggested you to check is if the species mass fraction gradient exist or not. These will be available only after issuing the command. Furthermore, which Fluent version are you using? If the version is older than 13.0, then you will not be able to use this command.

[mahdi-united]

Originally Posted by vinerm

Are you using double quotes around the command? The command needs to have bracket around it but no double quotes.

Secondly, contours of species mass fraction will always exist if species transport is enabled. What I suggested you to check is if the species mass fraction gradient exist or not. These will be available only after issuing the command. Furthermore, which Fluent version are you using? If the version is older than 13.0, then you will not be able to use this command.

no this message exactly wrote by me:

(rpsetvar 'species/save-gradients? #t)


and contour of species mass fraction gradients not exist!!!
also contour of vapor pressure not exist too but contour of volume fraction, temperature , velocity, density, pressure gradients exist
my version in 19.5

[vinerm]

If Fluent is not accepting the command to save species gradients then there is problem with the case setup. Species gradients can be extracted without this command as well, using the standard UDF commands as you were doing earlier, however, the command does the same thing. If the command is not working, there is some issue with your case setup. It could either be related to multiphase or species transport setup.

[mahdi-united]

Originally Posted by vinerm

If Fluent is not accepting the command to save species gradients then there is problem with the case setup. Species gradients can be extracted without this command as well, using the standard UDF commands as you were doing earlier, however, the command does the same thing. If the command is not working, there is some issue with your case setup. It could either be related to multiphase or species transport setup.

yes your right
i investigate it and say you
thank you very mich

[mahdi-united]

Originally Posted by vinerm

If Fluent is not accepting the command to save species gradients then there is problem with the case setup. Species gradients can be extracted without this command as well, using the standard UDF commands as you were doing earlier, however, the command does the same thing. If the command is not working, there is some issue with your case setup. It could either be related to multiphase or species transport setup.

please send your email for me
mahdi1372rs@gmail.com

[scorpian]

Originally Posted by vinerm

Look at the source listing in your installation

./ansys_inc/vXXX/fluent/fluentXX.Y.Z/src

How to calculate the gradient of species mole fraction in fluent?

[scorpian]

Originally Posted by vinerm

T_derivatives function is declared in pbns/sg.h, however, I do not think that it is relevant for you. You need to fetch gradients of mass fractions of species. That is accessible via C_YI_G or as stated earlier, using SV_Y_G, 0.

What error do you get if you use either C_YI_G or SV_Y_G? I would recommend the former since that is an easy wrapper for users.

Hello sir,

I was trying to get calculate the gradients of species mass and mole fraction in fluent. I could find the command for gradient of species mass fraction from your chat in this platform.

Could you help me how to get the gradient of species mole fraction in ANSYS-FLUENT?

Thanking you in anticipation,

With warm wishes,
Debojit Sharma