## Fluids

#### Perforated Wall Boundary Condition

• Danielgkh
Subscriber

Hi,

does anyone have experience working with perforated wall boundary condition?

I have a model where air is flowing along a perforated plate in absoprtion muffler. The perforated plate has around 4000 holes which is not really feasible to mesh them. It is also not possible to use symmetry BC as the muffler consist of other component. I am interested in the pressure or vortex forming or noise level at the lip of the plate. Is it possible to do so?

From Ansys Fluent user guide, it says this boundary condition only works for velocity and temperature field. I am wondering, if it will really show up, when I plot a velocity or temperatue contour. As in, small passages of flow from one side of the plate to the other.

• DrAmine
Ansys Employee
Try in a small example to get familiar with that boundary: we are extending the perforated wall boundary.
• Danielgkh
Subscriber

for some reason, I could not find the perforated wall BC option in Fluent from the wall type drop down list.

• Rob
Ansys Employee
• DrAmine
Ansys Employee
It is not a wall BC. It is a complete separate framework.
• Danielgkh
Subscriber

no, the other side is fluid. The example is like a sandwich, fluid at both side, solid at the middle.
If the other side is solid, then the gas can only flow past the perforated plate, but not through it.
• Danielgkh
Subscriber
Hi if so, where do one find it?
• DrAmine
Ansys Employee
Double Click on Boundary Conditions in the tree. They will appear where Operating Conditions Button is.
• Danielgkh
Subscriber
Thanks, I have found it. I didn't realize it just now.
• DrAmine
Ansys Employee
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• alex.purvis.572
Subscriber

Hi, I'm researching the effects of a porous wall in a transonic wind tunnel. I have a UDF from a previous study to model the porous wall as a mass flow outlet but I'd like to compare this to the inbuilt porous/perforated wall setting in fluent. I have the porous wall currently set, obviously, as a wall but when I try to change the setting to Perforated Wall in the Boundary Conditions settings as suggested by @DrAmine, the button appears greyed out. Can anyone suggest a reason for this? It's not the first problem I've had like this - I had a file that worked perfectly on my supervisor's computer but when opened in mine it kept resetting the properties of air and not giving me access to the dropdown box. Turned out to be a version issue but we use the same version now so I don't know how to implement the perforated wall. Please Help