Different Boundary Conditions for Standard Abaqus

NEWS.md

@@ -9,6 +9,8 @@ for human readability.
 #### Added
 - AMR for hyperbolic-parabolic equations on 3D `P4estMesh`
 - `flux_hllc` on non-cartesian meshes for `CompressibleEulerEquations{2,3}D`
+- Different boundary conditions for quad/hex meshes in Abaqus format, even if not generated by HOHQMesh, 
+  can now be digested by Trixi in 2D and 3D.
 
 ## Changes when updating to v0.6 from v0.5.x
 

docs/make.jl

@@ -65,6 +65,7 @@ files = [
     "Adaptive mesh refinement" => "adaptive_mesh_refinement.jl",
     "Structured mesh with curvilinear mapping" => "structured_mesh_mapping.jl",
     "Unstructured meshes with HOHQMesh.jl" => "hohqmesh_tutorial.jl",
+    "P4est mesh from gmsh" => "p4est_from_gmsh.jl",
     # Topic: other stuff
     "Explicit time stepping" => "time_stepping.jl",
     "Differentiable programming" => "differentiable_programming.jl",

docs/src/meshes/p4est_mesh.md

@@ -55,7 +55,7 @@ This heading is used to indicate to the mesh constructor which of the above mapp
 create a curvilinear mesh.
 If the Abaqus file header is **not** present then the `P4estMesh` is created with the first strategy above.
 
-#### List of corner nodes
+#### <a name="nodes"></a>List of corner nodes
 
 Next, prefaced with `*NODE`, comes a list of the physical `(x,y,z)` coordinates of all the corners.
 The first integer in the list of the corners provides its id number.
@@ -71,7 +71,7 @@ Thus, for the two-dimensional example mesh this block of corner information is
 7, 3.0, -1.0, 0.0
 ```
 
-#### List of elements
+#### <a name="elements"></a>List of elements
 
 The element connectivity is given after the list of corners. The header for this information block is
 ```
@@ -98,7 +98,9 @@ The construction of the element neighbor ids and identifying physical boundary s
 directly from the [`p4est`](https://github.com/cburstedde/p4est) library.
 For example, the neighbor connectivity is created in the mesh constructor using the wrapper `read_inp_p4est` function.
 
-#### HOHQMesh boundary information
+#### Encoding of boundaries
+
+##### HOHQMesh boundary information
 
 If present, any additional information in the mesh file that was created by `HOHQMesh` is prefaced with
 `** ` to make it an Abaqus comment.
@@ -230,8 +232,38 @@ For completeness, we provide the entire Abaqus mesh file for the example mesh in
 **  Bottom --- Right ---
 ```
 
+##### Standard Abaqus format boundary information
+
+As an alternative to an Abaqus mesh generated by `HOHQMesh`, `.inp` files with boundary information encoded as nodesets `*NSET,NSET=` can be used to construct a `p4est` mesh.
+This is especially useful for usage of existing meshes (consisting of bilinear elements) which could stem from the popular [`gmsh`](https://gmsh.info/) meshing software.
+
+In addition to the list of [nodes](#nodes) and [elements](#elements) given above, there are nodesets of the form 
+```
+*NSET,NSET=PhysicalLine1
+1, 4, 52, 53, 54, 55, 56, 57, 58, 
+```
+present which are used to associate the edges defined through their corner nodes with a label, in this case `PhysicalLine1`.
+By looping over every element and its associated edges, consisting of two nodes, we query the read in `NSET`s if the current node pair is present.
+
+To prevent that every nodeset following `*NSET,NSET=` is treated as a boundary, the user must supply a `boundary_symbols` keyword to the [`P4estMesh`](@ref) constructor:
+
+```julia
+boundary_symbols = [:PhysicalLine1]
+
+mesh = P4estMesh{2}(mesh_file, polydeg = polydeg, boundary_symbols = boundary_symbols)
+```
+By doing so, only nodesets with a label present in `boundary_symbols` are treated as physical boundaries.
+Other nodesets that could be used for diagnostics are not treated as external boundary.
+Note that there is a leading colon `:` compared to the label in the `.inp` mesh file.
+This is required to turn the label into a [`Symbol`](https://docs.julialang.org/en/v1/manual/metaprogramming/#Symbols).
+
+A 2D example for this mesh read-in for an unstructured mesh file created with `gmsh` is presented in 
+`examples/p4est_2d_dgsem/elixir_euler_NACA6412airfoil_mach2.jl`.
+
 ### Mesh in three spatial dimensions
 
+#### `HOHQMesh`-Extended Abaqus format
+
 The 3D Abaqus file format with high-order boundary information from `HOHQMesh` is very similar to the
 2D version discussed above. There are only three changes:
 
@@ -346,4 +378,222 @@ transfinite map of the straight sided hexahedral element to find
 \mathbf{X}(\boldsymbol{\xi}) = \boldsymbol\Sigma(\boldsymbol{\xi})
                              - \mathcal{C}_{\texttt{edge}}(\boldsymbol{\xi})
                              + \mathbf{X}_{linear}(\boldsymbol{\xi}).
+```
+
+#### Construction from standard Abaqus
+
+Also for a mesh in standard Abaqus format there are no qualitative changes when going from 2D to 3D.
+The most notable difference is that boundaries are formed in 3D by faces defined by four nodes while in 2D boundaries are edges consisting of two elements.
+A simple mesh file used also in `examples/p4est_3d_dgsem/elixir_euler_free_stream_boundaries.jl` is given below:
+```
+*Heading
+<SOMETHING DIFFERENT FROM "File created by HOHQMesh">
+*NODE
+1, -2, 0, 0
+2, -1, 0, 0
+3, -1, 1, 0
+4, -2, 1, 0
+5, -2, 0, 1
+6, -1, 0, 1
+7, -1, 1, 1
+8, -2, 1, 1
+9, -1.75, 1, 0
+10, -1.5, 1, 0
+11, -1.25, 1, 0
+12, -1, 0.75000000000035, 0
+13, -1, 0.50000000000206, 0
+14, -1, 0.25000000000104, 0
+15, -1.25, 0, 0
+16, -1.5, 0, 0
+17, -1.75, 0, 0
+18, -2, 0.24999999999941, 0
+19, -2, 0.49999999999869, 0
+20, -2, 0.74999999999934, 0
+21, -1.75, 0, 1
+22, -1.5, 0, 1
+23, -1.25, 0, 1
+24, -1, 0.24999999999941, 1
+25, -1, 0.49999999999869, 1
+26, -1, 0.74999999999934, 1
+27, -1.25, 1, 1
+28, -1.5, 1, 1
+29, -1.75, 1, 1
+30, -2, 0.75000000000035, 1
+31, -2, 0.50000000000206, 1
+32, -2, 0.25000000000104, 1
+33, -2, 0, 0.24999999999941
+34, -2, 0, 0.49999999999869
+35, -2, 0, 0.74999999999934
+36, -2, 1, 0.24999999999941
+37, -2, 1, 0.49999999999869
+38, -2, 1, 0.74999999999934
+39, -1, 0, 0.24999999999941
+40, -1, 0, 0.49999999999869
+41, -1, 0, 0.74999999999934
+42, -1, 1, 0.24999999999941
+43, -1, 1, 0.49999999999869
+44, -1, 1, 0.74999999999934
+45, -1.25, 0.25000000000063, 0
+46, -1.25, 0.50000000000122, 0
+47, -1.25, 0.7500000000001, 0
+48, -1.5, 0.25000000000023, 0
+49, -1.5, 0.50000000000038, 0
+50, -1.5, 0.74999999999984, 0
+51, -1.75, 0.24999999999982, 0
+52, -1.75, 0.49999999999953, 0
+53, -1.75, 0.74999999999959, 0
+54, -1.75, 0.25000000000063, 1
+55, -1.75, 0.50000000000122, 1
+56, -1.75, 0.7500000000001, 1
+57, -1.5, 0.25000000000023, 1
+58, -1.5, 0.50000000000038, 1
+59, -1.5, 0.74999999999984, 1
+60, -1.25, 0.24999999999982, 1
+61, -1.25, 0.49999999999953, 1
+62, -1.25, 0.74999999999959, 1
+63, -2, 0.24999999999982, 0.24999999999941
+64, -2, 0.49999999999953, 0.24999999999941
+65, -2, 0.74999999999959, 0.24999999999941
+66, -2, 0.25000000000023, 0.49999999999869
+67, -2, 0.50000000000038, 0.49999999999869
+68, -2, 0.74999999999984, 0.49999999999869
+69, -2, 0.25000000000063, 0.74999999999934
+70, -2, 0.50000000000122, 0.74999999999934
+71, -2, 0.7500000000001, 0.74999999999934
+72, -1.25, 1, 0.74999999999934
+73, -1.25, 1, 0.49999999999869
+74, -1.25, 1, 0.24999999999941
+75, -1.5, 1, 0.74999999999934
+76, -1.5, 1, 0.49999999999869
+77, -1.5, 1, 0.24999999999941
+78, -1.75, 1, 0.74999999999934
+79, -1.75, 1, 0.49999999999869
+80, -1.75, 1, 0.24999999999941
+81, -1, 0.25000000000063, 0.24999999999941
+82, -1, 0.50000000000122, 0.24999999999941
+83, -1, 0.7500000000001, 0.24999999999941
+84, -1, 0.25000000000023, 0.49999999999869
+85, -1, 0.50000000000038, 0.49999999999869
+86, -1, 0.74999999999984, 0.49999999999869
+87, -1, 0.24999999999982, 0.74999999999934
+88, -1, 0.49999999999953, 0.74999999999934
+89, -1, 0.74999999999959, 0.74999999999934
+90, -1.75, 0, 0.74999999999934
+91, -1.75, 0, 0.49999999999869
+92, -1.75, 0, 0.24999999999941
+93, -1.5, 0, 0.74999999999934
+94, -1.5, 0, 0.49999999999869
+95, -1.5, 0, 0.24999999999941
+96, -1.25, 0, 0.74999999999934
+97, -1.25, 0, 0.49999999999869
+98, -1.25, 0, 0.24999999999941
+99, -1.75, 0.25000000000043, 0.74999999999934
+100, -1.75, 0.25000000000023, 0.49999999999869
+101, -1.75, 0.25000000000002, 0.24999999999941
+102, -1.75, 0.5000000000008, 0.74999999999934
+103, -1.75, 0.50000000000038, 0.49999999999869
+104, -1.75, 0.49999999999995, 0.24999999999941
+105, -1.75, 0.74999999999997, 0.74999999999934
+106, -1.75, 0.74999999999984, 0.49999999999869
+107, -1.75, 0.74999999999972, 0.24999999999941
+108, -1.5, 0.25000000000023, 0.74999999999934
+109, -1.5, 0.25000000000023, 0.49999999999869
+110, -1.5, 0.25000000000023, 0.24999999999941
+111, -1.5, 0.50000000000038, 0.74999999999934
+112, -1.5, 0.50000000000038, 0.49999999999869
+113, -1.5, 0.50000000000038, 0.24999999999941
+114, -1.5, 0.74999999999984, 0.74999999999934
+115, -1.5, 0.74999999999984, 0.49999999999869
+116, -1.5, 0.74999999999984, 0.24999999999941
+117, -1.25, 0.25000000000002, 0.74999999999934
+118, -1.25, 0.25000000000023, 0.49999999999869
+119, -1.25, 0.25000000000043, 0.24999999999941
+120, -1.25, 0.49999999999995, 0.74999999999934
+121, -1.25, 0.50000000000038, 0.49999999999869
+122, -1.25, 0.5000000000008, 0.24999999999941
+123, -1.25, 0.74999999999972, 0.74999999999934
+124, -1.25, 0.74999999999984, 0.49999999999869
+125, -1.25, 0.74999999999997, 0.24999999999941
+******* E L E M E N T S *************
+*ELEMENT, type=C3D8, ELSET=Volume1
+153, 54, 21, 5, 32, 99, 90, 35, 69
+154, 99, 90, 35, 69, 100, 91, 34, 66
+155, 100, 91, 34, 66, 101, 92, 33, 63
+156, 101, 92, 33, 63, 51, 17, 1, 18
+157, 55, 54, 32, 31, 102, 99, 69, 70
+158, 102, 99, 69, 70, 103, 100, 66, 67
+159, 103, 100, 66, 67, 104, 101, 63, 64
+160, 104, 101, 63, 64, 52, 51, 18, 19
+161, 56, 55, 31, 30, 105, 102, 70, 71
+162, 105, 102, 70, 71, 106, 103, 67, 68
+163, 106, 103, 67, 68, 107, 104, 64, 65
+164, 107, 104, 64, 65, 53, 52, 19, 20
+165, 29, 56, 30, 8, 78, 105, 71, 38
+166, 78, 105, 71, 38, 79, 106, 68, 37
+167, 79, 106, 68, 37, 80, 107, 65, 36
+168, 80, 107, 65, 36, 9, 53, 20, 4
+169, 57, 22, 21, 54, 108, 93, 90, 99
+170, 108, 93, 90, 99, 109, 94, 91, 100
+171, 109, 94, 91, 100, 110, 95, 92, 101
+172, 110, 95, 92, 101, 48, 16, 17, 51
+173, 58, 57, 54, 55, 111, 108, 99, 102
+174, 111, 108, 99, 102, 112, 109, 100, 103
+175, 112, 109, 100, 103, 113, 110, 101, 104
+176, 113, 110, 101, 104, 49, 48, 51, 52
+177, 59, 58, 55, 56, 114, 111, 102, 105
+178, 114, 111, 102, 105, 115, 112, 103, 106
+179, 115, 112, 103, 106, 116, 113, 104, 107
+180, 116, 113, 104, 107, 50, 49, 52, 53
+181, 28, 59, 56, 29, 75, 114, 105, 78
+182, 75, 114, 105, 78, 76, 115, 106, 79
+183, 76, 115, 106, 79, 77, 116, 107, 80
+184, 77, 116, 107, 80, 10, 50, 53, 9
+185, 60, 23, 22, 57, 117, 96, 93, 108
+186, 117, 96, 93, 108, 118, 97, 94, 109
+187, 118, 97, 94, 109, 119, 98, 95, 110
+188, 119, 98, 95, 110, 45, 15, 16, 48
+189, 61, 60, 57, 58, 120, 117, 108, 111
+190, 120, 117, 108, 111, 121, 118, 109, 112
+191, 121, 118, 109, 112, 122, 119, 110, 113
+192, 122, 119, 110, 113, 46, 45, 48, 49
+193, 62, 61, 58, 59, 123, 120, 111, 114
+194, 123, 120, 111, 114, 124, 121, 112, 115
+195, 124, 121, 112, 115, 125, 122, 113, 116
+196, 125, 122, 113, 116, 47, 46, 49, 50
+197, 27, 62, 59, 28, 72, 123, 114, 75
+198, 72, 123, 114, 75, 73, 124, 115, 76
+199, 73, 124, 115, 76, 74, 125, 116, 77
+200, 74, 125, 116, 77, 11, 47, 50, 10
+201, 24, 6, 23, 60, 87, 41, 96, 117
+202, 87, 41, 96, 117, 84, 40, 97, 118
+203, 84, 40, 97, 118, 81, 39, 98, 119
+204, 81, 39, 98, 119, 14, 2, 15, 45
+205, 25, 24, 60, 61, 88, 87, 117, 120
+206, 88, 87, 117, 120, 85, 84, 118, 121
+207, 85, 84, 118, 121, 82, 81, 119, 122
+208, 82, 81, 119, 122, 13, 14, 45, 46
+209, 26, 25, 61, 62, 89, 88, 120, 123
+210, 89, 88, 120, 123, 86, 85, 121, 124
+211, 86, 85, 121, 124, 83, 82, 122, 125
+212, 83, 82, 122, 125, 12, 13, 46, 47
+213, 7, 26, 62, 27, 44, 89, 123, 72
+214, 44, 89, 123, 72, 43, 86, 124, 73
+215, 43, 86, 124, 73, 42, 83, 125, 74
+216, 42, 83, 125, 74, 3, 12, 47, 11
+*NSET,NSET=PhysicalSurface1
+1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 
+11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 
+21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 
+31, 32, 33, 34, 35, 36, 37, 38, 45, 46, 
+47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 
+57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 
+67, 68, 69, 70, 71, 
+*NSET,NSET=PhysicalSurface2
+1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 
+11, 12, 13, 14, 15, 16, 17, 21, 22, 23, 
+24, 25, 26, 27, 28, 29, 33, 34, 35, 36, 
+37, 38, 39, 40, 41, 42, 43, 44, 72, 73, 
+74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 
+84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 
+94, 95, 96, 97, 98, 
 ```