define saline and hot water


      Hi Dears.

      My model is this:

      I have the flume with dimension 2x2x1.2 m that filled with water temperature=18 c, Salinity=0.7 PSU.

      The jet with diameter=4mm and angle=60 and temperature=40c, Salinity=8 PSU Discharged in the flume.

      I want density in every time and coordinate calculate based on temperature and salinity of this point with the table or relationship that i give to fluent.

      I have a few questions that I hope to friends guide me:

      1) How i can define this fluid (water that have temp and salinity)?

      2) How i can define this table or relationship in Fluent?

      I have asked this question several times from different people and unfortunately I have not made any results. Hope the friends answer me and explain it.



    • DrAmine
      Ansys Employee

      1/Defining the density with temperature and salinity dependency

      2/This dependency can be prescribed by reading from table, making some interpolation and the result will be the density

      Here you will require UDF. 


      Use the species transport model with two components Salinity (transported) and Water (constraint) and then prescribe at your domain inflow / outflow the mass fraction of salinity. For the mixture density a volume weighted mixing can be used.


      thank you abenhadj. but can you explain in the software environment the definition of fluid.

      Unfortunately, I am not very familiar with UDF. What kind of UDF? Can you give me more explanation about this UDF that i must provide? and do you have any UDF that is near to my case to i change it? [Except recommendation to read manual of fluent and search on the Internet    ]

      thank you so much.

    • DrAmine
      Ansys Employee

      As ANSYS Staff on a open community I have to stick to the suggestion to read carefully the Customization manual. You will need:

      1/DEFINE_PROPERTY to define the density

      2/C-user functions to read the table and build up a look-up based on the way you want to interpolate things.

      A lot of scientists are using the species approach to model sea water with different varying salinity and temperature.

    • Karthik R


      Please look at the customization manual. There are a lot of UDF examples in the manual. I found that the best way to writing a UDF is to take an existing one and modify it to serve your needs. Please use these examples to learn, understand, and simulate your results.

      Thank you.

      Best Regards,


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