[entropie]

Hello again,

I have a question to notation "U.boundaryField()[0][0]"

What does [0][0] mean? So far I understand, this should be a single point on the mesh, but is there an option to find out, where exactly this point is?

[alexeym]

Hi,

U.boundaryField() is a list of fvPatchFields, so

Info << U.boundaryField()[0].typeName << endl;

is

fvPatchField

(0 is ID of the patch of your mesh)

and finally U.boundaryMesh()[0][0] is a value of U in face 0 of the patch with ID == 0.

You can try to learn the location of the face using:

const polyPatch& ptch = mesh.boundaryMesh()[0];
Info << ptch.faceCentres()[0] << endl;

[entropie]

Hello Alexey,

thanks a lot!

But what do you mean by "0 is the ID of the patch of your mesh"? Can I somehow find out, what ID belongs to what patch?

Kind regards, Olivia

[alexeym]

Hi,

as you've used 0 in the code snippet, I've referenced to this 0

There are two methods of boundaryMesh:

1. patchNames - list of patch names, so you can get a name of patch with ID == 0 using something like mesh.boundaryMesh().patchNames()[0]

2. findPatchID - to lookup patch ID by its name, i.e. mesh.boundaryMesh().findPatchID("wall") will find ID of the patch with a name wall.

[entropie]

Hi

finally I've found it out. This

mesh.boundaryMesh().findPatchID("airfoil")

gave me this ID-number of the patch "airfoil".

I should type there "airfoil" and not "wall" or "patch". I think it is so because I may have more than one patch and more than one wall actually.

Thank you for your help again!

[alexeym]

Surely "wall" was just an example of the patch's name. Though my telepathic abilities are improving, I still wasn't able to guess names of the patches in your case

[entropie]

Well, I hope this is my last question to this matter...

There is a difference between

U.boundaryField ()[0][1]

and

U.boundaryMesh ()[0][1]

?

[alexeym]

Well, it's rather easy to check

First of all, U.boundaryMesh()[0][1] won't compile, as volVectorField doesn't have boundaryMesh() method. So it should be U.mesh().boundaryMesh()[0][1] (if you really need the boundary mesh).

Then you can use following snippet to find difference (or read documentation instead):

    Info<< U.boundaryField ()[0][1].typeName << endl;
    Info<< U.boundaryField ()[0][1] << endl;
    Info<< U.mesh().boundaryMesh ()[0][1].typeName << endl;
    Info<< U.mesh().boundaryMesh ()[0][1] << endl;

the output will be something like

vector
(0 0 0)
face
4(51 357 408 102)

[entropie]

Thank you sooooo much!