Need a simple way to apply BCs to _all_ boundaries #30221
Description
Motivation
Looking at the code for BoundaryRestrictable one might get the impression that an empty boundary list, or the special boundary name ANY_BOUNDARY_ID would apply the BC simply to all boundaries in the simulation. However that's not the case.
[Mesh]
[gen]
type = GeneratedMeshGenerator
dim = 2
nx = 10
ny = 10
[]
[]
[Variables]
[u]
[]
[]
[Kernels]
[dt]
type = TimeDerivative
variable = u
[]
[diff]
type = Diffusion
variable = u
[]
[body_force]
type = BodyForce
variable = u
function = 1.0
[]
[]
[BCs]
[zero]
type = DirichletBC
variable = u
value = 0.0
# boundary = ''
boundary = 'ANY_BOUNDARY_ID' # This will match any boundary, including node sets and side sets
# boundary = 'left right top bottom'
[]
[]
[Postprocessors]
[int]
type = ElementIntegralVariablePostprocessor
variable = u
[]
[]
[Executioner]
type = Transient
num_steps = 10
dt = 0.1
[]
[Outputs]
exodus = true
[]
Design
Let's discuss what's in the code and whether we want to make the half implemented (?) behavior more consistent. Why - for example - wouldn't we make the boundary parameter optional, just like the block parameter, where not specifying it just means "no restriction"...?
Impact
More consistent application behavior. @jessecarterMOOSE