Buoyancy force term in Fluent

Cooper24 · August 23, 2021, 01:45

I am modeling laser melting of a solid. Above the melting point, a Buoyancy force should act. Do I need to add this Buoyancy force separately through a UDF? I understand that gravity is there in the momentum equation. Above the melting point, a Buoyancy force is added. So, is it automatically added by Fluent or I need to add is using an external source term in the UDF?
I am using VOF with Solidification/Melting in FLUENT.

rupak504 · August 27, 2021, 11:49

Quote:

Originally Posted by Cooper24

Above the melting point, a Buoyancy force is added.

Why do we need to add a separate buoyancy force as a source term in the above melting point cases?

Cooper24 · August 27, 2021, 16:58

Hi, I am not sure. I am asking whether we need to add it separately using a UDF or FLUENT automatically adds it. I am confused because I haven't given coefficient of volumetric expansion in the properties section.

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August 27, 2021, 16:58		#3
Cooper24 Member Join Date: Jul 2020 Location: India Posts: 63 Rep Power: 5	Hi, I am not sure. I am asking whether we need to add it separately using a UDF or FLUENT automatically adds it. I am confused because I haven't given coefficient of volumetric expansion in the properties section.