Reading boundaries from a libmesh (XDA) file.

[danielwardstfc]

I have a libmesh mesh file (.xda) that looks a bit like this:

libMesh-0.7.0+
          48 # number of elements
         105 # number of nodes
           . # boundary condition specification file
         n/a # subdomain id specification file
         n/a # processor id specification file
         n/a # p-level specification file
          48 # n_elem at level 0, [ type (n0 ... nN-1) ]
          10          36          43           8           1           0           7          42          35
          10          37          44           9           2           1           8          43          36
etc...
           0           0           0
    0.166667           0           0
    0.333333           0           0
etc...
           4# number of boundary conditions
           0           1           0
           6           1           0
etc...
          23           5           0
          24           5           1
          30           5           1
etc...

This hopefully illustrates that there are four boundary conditions in this XDA file, each with a tag from 0 to 3 (here some examples with tags 0 and 1 are shown). I'm trying to read this into MOOSE and can successfully do so with an empty BCs section in my input file. However, when I try and read the boundaries I run into issues with MOOSE not being able to see the boundaries. Here's my input file

[Mesh]
  file = in/mesh_singleCylinder.xda
[]

[Variables]
  [T]
    order = FIRST
    family = LAGRANGE
  []
[]

[Kernels]
  [T]
    type = NullKernel
    variable = T
  []
[]

[BCs]
  [./bottom]
    type = DirichletBC
    variable = T
    boundary = 0
    value = 1
  [../]
  [./top]
    type = DirichletBC
    variable = T
    boundary = 1
    value = 0
  [../]
[]

[Executioner]
  type = Steady
  solve_type = 'PJFNK'
[]

[Outputs]
  execute_on = 'timestep_end'
  exodus = true
[]

[UserObjects]
[]

[Functions]
[]

and here's the error:

(BCs/top/boundary): the following node sets (ids) do not exist on the mesh: 1

I expected it to read the tags from the boundary section but it isn't. Does anybody know why?

Best,

Daniel

[GiudGiud]

Hello

Can you paste the output of your run but with --mesh-only on the command line

Guillaume

[danielwardstfc]

Hi Guillaume,

Thanks for responding so fast! I get this output:

 Mesh Information:
  elem_dimensions()={3}
  spatial_dimension()=3
  n_nodes()=360
    n_local_nodes()=360
  n_elem()=264
    n_local_elem()=264
    n_active_elem()=264
  n_subdomains()=1
  n_elemsets()=0
  n_partitions()=1
  n_processors()=1
  n_threads()=1
  processor_id()=0
  is_prepared()=true
  is_replicated()=true

 Mesh Bounding Box:
  Minimum: (x,y,z)=(-0.965926, -0.965926,        0)
  Maximum: (x,y,z)=(0.965926, 0.965926,  8.16667)
  Delta:   (x,y,z)=( 1.93185,  1.93185,  8.16667)

 Mesh Element Type(s):
  HEX8

 Mesh Nodesets:
  Nodeset 0, 8 nodes
   Bounding box minimum: (x,y,z)=(-0.620386, -0.620386,        0)
   Bounding box maximum: (x,y,z)=(-0.172842, 0.620386,        0)
   Bounding box delta: (x,y,z)=(0.447544,  1.24077,        0)

 Mesh Sidesets:
  Sideset 0, 3 sides (QUAD4), 3 elems (HEX8), 8 nodes
   Side volume: 0.408139
   Bounding box minimum: (x,y,z)=(-0.620386, -0.620386,        0)
   Bounding box maximum: (x,y,z)=(-0.172842, 0.620386,        0)
   Bounding box delta: (x,y,z)=(0.447544,  1.24077,        0)

 Mesh Edgesets:
  None

 Mesh Subdomains:
  Subdomain 0: 264 elems (HEX8, 264 active), 360 active nodes
   Volume: 24.5
   Bounding box minimum: (x,y,z)=(-0.965926, -0.965926,        0)
   Bounding box maximum: (x,y,z)=(0.965926, 0.965926,  8.16667)
   Bounding box delta: (x,y,z)=( 1.93185,  1.93185,  8.16667)
  Global mesh volume = 24.5

WARNING! There are options you set that were not used!
WARNING! could be spelling mistake, etc!
There are 2 unused database options. They are:
Option left: name:--mesh-only (no value) source: command line
Option left: name:-i value: 02_boundaryCheck.i source: command line

which I think has worked, despite the warnings.

[GiudGiud]

Hello

So the only boundary that is being recognized is the '0' indexed one.
I would create an issue in MOOSE if it does not exist already
then use the MeshGenerator system to re-create the boundaries in MOOSE
https://mooseframework.inl.gov/syntax/Mesh/index.html#a6ba103a-75a3-4a72-9a8a-934024667c93

Guillaume

[danielwardstfc]

Okay, I've submitted an issue. Thank you

[lindsayad]

issue created is: #27153