Two-sided walls
 

I'm trying to understand what's the difference between the originally wall that I have defined in my domain and the automaticly created "Shadow Wall".
I have a wall in contact to a fluid zone but this wall is coated" with a small sheet.
Then I have two wall next to the fluid, the originally one and his Shadow, and I have to define the thickness of the sheet, and here is the problem; I have to define the thickness in the originally zone or in the shadow zone?.
And... the shadow zone is nearer of the solid or of the fluid?.

I'll be grateful to someone who can helps me!:confused:

Regards!

Well I think you put one of your original walls as interface. Fluent automatically creates a shadow wall in that case. Or, if in your geometry you combine all of your parts then at those walls where your fluid and solid zones interact, shadow wall is created by fluent. This shadow wall or two-sided wall acts as coupling between the solid and fluid zone. e.g. if one is modeling conjugate heat transfer, then to creation of shadow walls instructs fluent to consider the conduction within the solid and the convection to the fluid.

I think you must put your thickness to the original wall although, I request you to share your geometry and description of the problem so that we can get a clear picture.