Theory
A perforated wall is an internal face (a face between two fluid regions after the bodies have been split along each other) whose holes are not drawn in the CAD. Instead of meshing the holes, the flow solver models the wall as a pressure jump across a zero-thickness baffle (see Perforation type and Open-area ratio), and the acoustic solver models it as a transfer impedance between its two sides.
Each perforated wall has ONE set of properties (open-area ratio, hole diameter, thickness, loss model, acoustic impedance model) on its own card on the Boundary Conditions step. A wall may comprise several faces, for example both halves of a perforated tube split in the CAD. Group only faces of the same tube or plate, because the grazing-flow estimate fits a single cylinder to the faces of a wall.
Default and rule
- Default
- 0 (or the number the faces already use)
- Rule
0 for a new model. When the assignment already uses perforated walls (a restored session, a replaced model), the count starts at the highest one in use.
- Source
The patch naming is defined by the program's patch assignment.
Valid range integer >= 0; never below the highest perforated wall in use
Values
Whole numbers from 0. The number cannot be lowered below the highest perforated wall to which a face is assigned.
Meshing
A case with perforated walls is meshed serially (createPatch turns each wall into a cyclic pair after the mesher); the solution still runs in parallel.