# SpiralAnnularMesh

This mesh is derived from MooseMesh. It has an annular shape, and nodes are located on different concentric rings between the inner and outer circles. The elements are triangular.

Here are the required parameters :

• inner_radius

• outer_radius

• nodes_per_ring

• num_rings

Given all these parameters, the radial bias will be computed automatically.

It is also possible to specify if you want a second-order Mesh : TRI3 elements will become TRI6 elements. To do that, simply change the use_tri6 parameter to true.

## Example Input File

For example, with the following input file :


[Mesh]
type = SpiralAnnularMesh
use_tri6 = true
nodes_per_ring = 18
num_rings = 10
[]


The resulting mesh looks like this :

## Input Parameters

• num_ringsThe number of rings.

C++ Type:unsigned int

Options:

Description:The number of rings.

• nodes_per_ringNumber of nodes on each ring.

C++ Type:unsigned int

Options:

Description:Number of nodes on each ring.

• outer_radiusThe size of the outer circle. Logically, it has to be greater than inner_radius

C++ Type:double

Options:

Description:The size of the outer circle. Logically, it has to be greater than inner_radius

• inner_radiusThe size of the inner circle.

C++ Type:double

Options:

Description:The size of the inner circle.

### Required Parameters

• exterior_bid2The boundary id to use for the exterior (outer circle)

Default:2

C++ Type:short

Options:

Description:The boundary id to use for the exterior (outer circle)

• use_tri6FalseGenerate mesh of TRI6 elements instead of TRI3 elements.

Default:False

C++ Type:bool

Options:

Description:Generate mesh of TRI6 elements instead of TRI3 elements.

• allow_renumberingTrueIf allow_renumbering=false, node and element numbers are kept fixed until deletion

Default:True

C++ Type:bool

Options:

Description:If allow_renumbering=false, node and element numbers are kept fixed until deletion

• initial_delta_rWidth of the initial layer of elements around the cylinder.This number should be approximately 2 * pi * inner_radius / nodes_per_ring to ensure that the initial layer of elements is almost equilateral

C++ Type:double

Options:

Description:Width of the initial layer of elements around the cylinder.This number should be approximately 2 * pi * inner_radius / nodes_per_ring to ensure that the initial layer of elements is almost equilateral

• parallel_typeDEFAULTDISTRIBUTED: Always use libMesh::DistributedMesh REPLICATED: Always use libMesh::ReplicatedMesh DEFAULT: Use libMesh::ReplicatedMesh unless --distributed-mesh is specified on the command line

Default:DEFAULT

C++ Type:MooseEnum

Options:DISTRIBUTED REPLICATED DEFAULT

Description:DISTRIBUTED: Always use libMesh::DistributedMesh REPLICATED: Always use libMesh::ReplicatedMesh DEFAULT: Use libMesh::ReplicatedMesh unless --distributed-mesh is specified on the command line

• cylinder_bid1The boundary id to use for the cylinder (inner circle)

Default:1

C++ Type:short

Options:

Description:The boundary id to use for the cylinder (inner circle)

• ghosting_patch_sizeThe number of nearest neighbors considered for ghosting purposes when 'iteration' patch update strategy is used. Default is 5 * patch_size.

C++ Type:unsigned int

Options:

Description:The number of nearest neighbors considered for ghosting purposes when 'iteration' patch update strategy is used. Default is 5 * patch_size.

• max_leaf_size10The maximum number of points in each leaf of the KDTree used in the nearest neighbor search. As the leaf size becomes larger,KDTree construction becomes faster but the nearest neighbor searchbecomes slower.

Default:10

C++ Type:unsigned int

Options:

Description:The maximum number of points in each leaf of the KDTree used in the nearest neighbor search. As the leaf size becomes larger,KDTree construction becomes faster but the nearest neighbor searchbecomes slower.

### Optional Parameters

• dim1This is only required for certain mesh formats where the dimension of the mesh cannot be autodetected. In particular you must supply this for GMSH meshes. Note: This is completely ignored for ExodusII meshes!

Default:1

C++ Type:MooseEnum

Options:1 2 3

Description:This is only required for certain mesh formats where the dimension of the mesh cannot be autodetected. In particular you must supply this for GMSH meshes. Note: This is completely ignored for ExodusII meshes!

• nemesisFalseIf nemesis=true and file=foo.e, actually reads foo.e.N.0, foo.e.N.1, ... foo.e.N.N-1, where N = # CPUs, with NemesisIO.

Default:False

C++ Type:bool

Options:

Description:If nemesis=true and file=foo.e, actually reads foo.e.N.0, foo.e.N.1, ... foo.e.N.N-1, where N = # CPUs, with NemesisIO.

• patch_update_strategyneverHow often to update the geometric search 'patch'. The default is to never update it (which is the most efficient but could be a problem with lots of relative motion). 'always' will update the patch for all slave nodes at the beginning of every timestep which might be time consuming. 'auto' will attempt to determine at the start of which timesteps the patch for all slave nodes needs to be updated automatically.'iteration' updates the patch at every nonlinear iteration for a subset of slave nodes for which penetration is not detected. If there can be substantial relative motion between the master and slave surfaces during the nonlinear iterations within a timestep, it is advisable to use 'iteration' option to ensure accurate contact detection.

Default:never

C++ Type:MooseEnum

Options:never always auto iteration

Description:How often to update the geometric search 'patch'. The default is to never update it (which is the most efficient but could be a problem with lots of relative motion). 'always' will update the patch for all slave nodes at the beginning of every timestep which might be time consuming. 'auto' will attempt to determine at the start of which timesteps the patch for all slave nodes needs to be updated automatically.'iteration' updates the patch at every nonlinear iteration for a subset of slave nodes for which penetration is not detected. If there can be substantial relative motion between the master and slave surfaces during the nonlinear iterations within a timestep, it is advisable to use 'iteration' option to ensure accurate contact detection.

• control_tagsAdds user-defined labels for accessing object parameters via control logic.

C++ Type:std::vector

Options:

Description:Adds user-defined labels for accessing object parameters via control logic.

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

Description:Set the enabled status of the MooseObject.

• construct_node_list_from_side_listTrueWhether or not to generate nodesets from the sidesets (usually a good idea).

Default:True

C++ Type:bool

Options:

Description:Whether or not to generate nodesets from the sidesets (usually a good idea).

• patch_size40The number of nodes to consider in the NearestNode neighborhood.

Default:40

C++ Type:unsigned int

Options:

Description:The number of nodes to consider in the NearestNode neighborhood.

• partitionerdefaultSpecifies a mesh partitioner to use when splitting the mesh for a parallel computation.

Default:default

C++ Type:MooseEnum

Options:default metis parmetis linear centroid hilbert_sfc morton_sfc

Description:Specifies a mesh partitioner to use when splitting the mesh for a parallel computation.

• centroid_partitioner_directionSpecifies the sort direction if using the centroid partitioner. Available options: x, y, z, radial

C++ Type:MooseEnum