airflow over tubes filled with PCM
I facing a problem in Ansys Fluent.
I'm simulating a 2D box that contains tubes filled with PCM.
the problem is in defining the wall of the tubes. By default, Fluent defines those walls of the tubes as external walls where you have to choose heat flux or convection ...etc but it has to be coupled wall type right? and if I tried to define those walls as interface the simulations won't begin because it gives me this error :
WARNING: Unassigned interface zone detected for interface 20
Error: Init_Flow: unassigned interface_zones
Error Object: ()
please! does anyone knows how to deal with this kind of problem? I literally tried everything that I can come up with but unfortunately, nothing works.
Thank you in advance,