Reply To: Simulating Selective Laser Melting process in Ansys Fluent – UDF issue

[Rob]

If you check the various examples you'll see Fluent has macros to call cell data, eg https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v242/en/flu_udf/flu_udf_DataAccessMacros.html  

You may have added the momentum source, but have the criterion of C_VOF and C_T been met to give a non zero value of source (heat_source)?