All walls should have adjacent zone as fluid and their shadow zone as solid, for a model containing many solid and fluid zones.
When a mesh file for a model having many solid and fluid zones is read in Fluent, it creates wall and
wall-shadow boundary zones. Some of these walls will have adjacent zone as fluid and some will have solids
simillarly wall-shadow will have fluid and solid as their adjacent zones. For post processing will be efficient if we
have all wall's having their adjacent zones as fluid and wall-shadow's will have adjacent zone as solid.
Following solution will help to achieve this.
When a mesh file is read in Fluent, the face normals of the wall pointing in a fluid zone, will have adjacent zone
as fluid and wall-shadow will have solid as adjacent zone. Similarly for wall whose face normals point in solid
zone will have adjacent zone as solid and its shadow zone will have fluid adjacent to it.
After reading the mesh file in Fluent, find the walls whose adjacent zone is solid, and you want their adajcent
zone to be as fluid.
Read the mesh file in Tgrid and flip the normals of all the walls who had adjacent zone as solid instead of fluid.
The normals can be flipped through, Boundary-->Zones-->select all the desired walls, underFace zones and
under option select Flip Normals, then click on Apply. Write out the mesh file and read in Fluent, it will have all
the walls with adjacent zone as fluid and their shadow zones as solid.