Confused with wall boundaries in 3D
 

Hello!

I am modelling a cube with gas inside. Two sides of the cube have to be holes while the other four sides have to be walls. I have a patch for the holes and one for the walls.

In the blockMeshDict they're:

patch sides
(
(1 2 6 5)
(0 4 7 3)
)
wall walls
(
(0 1 5 4)
(5 6 7 4)
(3 7 6 2)
(0 3 2 1)
)

And in the 0/p they're:

boundaryField
{
sides
{
type zeroGradient;
}
walls
{
type zeroGradient;
}
}

Is this a false setting for walls to be walls and sides to be holes?:confused:

Your wall BC seems OK. The holes are either inlets or outlets. If inlet zeroGradient is OK for pressure in addition you need a fixedValue for the normal velocity. If outlet the pressure should be a fixedValue.
rgds
Bjorn

Thanks a lot! And for T is the same? And for U? I did it this way:

T)

boundaryField
{
outlet
{
type fixedValue;
value uniform 300;
}
walls
{
type zeroGradient;
}
}



U)

outlet
{
type fixedValue;
value uniform (0 0 0);
}
walls
{
type fixedValue;
value uniform (0 0 0);
}