Ansys Employee
Yes, you need to have it set for Internal. In the above image it's clear there's a wall in the way so no flow reaches the turbine. An internal boundary is a labelled surface in the mesh that doesn't have any effect on the fluid flow. If you didn't use inflation in the mesh you can just convert one of the wall wall:shadow pair to interior (near enough the same as an internal) via the boundary conditions panel in Fluent.