[kakila]

OpenFoam v10 introdcued this change https://github.com/OpenFOAM/OpenFOAM...0b501f27a570c3
that forces the explicit defintion of the defaultPatch to avoid a bug.

Once the defaultPatch (I named it background) is defined as explained in the commit serial Meshing works just fine. However parallel meshing does not work. In particular decomposePar fails:

$ decomposePar -force
/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  10
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
Build  : 10-e450dce21ea5
Exec   : decomposePar -force
Date   : Jan 05 2023
Time   : 17:17:32

...

Processor 11
    Number of cells = 14671
    Number of faces shared with processor 2 = 270
    Number of faces shared with processor 4 = 364
    Number of faces shared with processor 5 = 56
    Number of faces shared with processor 6 = 347
    Number of faces shared with processor 8 = 159
    Number of faces shared with processor 9 = 410
    Number of faces shared with processor 10 = 1079
    Number of processor patches = 7
    Number of processor faces = 2685
    Number of boundary faces = 1519

Number of processor faces = 13492
Max number of cells = 14848 (0.996497% above average 14701.5)
Max number of processor patches = 7 (40% above average 5)
Max number of faces between processors = 2963 (31.767% above average 2248.67)

Time = 0s

--> FOAM FATAL IO ERROR: 
Cannot find patchField entry for background

file: /home/juanpi/Projects/OST/WABEsense/wabe-cfd/scratch/single_case_AMR/detailed/0/alpha.water/boundaryField from line 41 to line 21.

    From function void Foam::GeometricBoundaryField<Type, PatchField, GeoMesh>::readField(const Foam::DimensionedField<TypeR, GeoMesh>&, const Foam::dictionary&) [with Type = double; PatchField = Foam::fvPatchField; GeoMesh = Foam::volMesh]
    in file /home/ubuntu/OpenFOAM/OpenFOAM-10/src/OpenFOAM/lnInclude/GeometricBoundaryField.C at line 187.

FOAM exiting

If I add a BC for the default patch background in all the fields in the 0 folder, then it works.

Is this expected or a bug? It is very annoying to define a BC for a non-existing patch.