[Anna Tian]

Hi,

When I define an fluid-fluid interface, I need to choose GGI surface at each side of those two fluid domains. May i ask could one be larger than another one? ( They have difference size but the large one include the small one. )

[ghorrocks]

Yes, a GGI interface can have non-overlap sections. By default this section of the GGI gets a adiabatic slip wall applied to it, but you can change this to any condition you like in the interface conditions.