SURFACE_SET

Specifies topological information for a set of surface elements.

Type

AcuSolve Command

Syntax

SURFACE_SET ("name") { parameters...}

Qualifier

User-given name.

Parameters

type (enumerated) [default]
Type of surface set.
default
Mesh topology are given in shape, volume_set and surfaces parameters.
dynamic
Mesh topology will be set in AcuPrep. Used with THERMAL_Shell only.
shape (enumerated) [no default]
Shape of the elements. For type = default only.
three_node_triangle or tri3
Three-node triangle.
four_node_quad or quad4
Four-node quadrilateral.
six_node_triangle or tri6
Six-node triangle.
surfaces (array) [no default]
A set of surface element connectivity. For type = default only.
volume_set or vol_set (string) [no default]
User-given name of the parent volume set. For type = default only.
dynamic_type (enumerated) [no default]
Type of dynamic surface_set.
shell_inner
If this option is selected, this will be used for the inner surface_set of the AcuPrep created THERMAL_SHELL.
shell_outer
If this option is selected, this will be used for the outer surface_set of the AcuPrep created THERMAL_SHELL.
reference_surface_set (string) [no default]
Name of the surface_set used in THERMAL_SHELL. Surface_set adjacent to this one will be called shell_inner while surface_set on the other side of the THERMAL_SHELL will be shell_outer. Valid for type = dynamic only.

Description

The purpose of the SURFACE_SET command is to simply act as a container that is later referenced by other commands that take surface elements as an input. All elements in a given SURFACE_SET have the same shape and parent VOLUME_SET, but the SURFACE_SET container enables subsequent commands to accept mixed topologies. For example, consider a simulation which contains tetrahedra and prism elements. These surface elements are read into separate SURFACE_SET containers, which reference their parent volume sets:
VOLUME_SET( "tetrahedra" ) {
    elements       = { 1, 1, 2, 4, 3 ;
                       2, 3, 4, 6, 5 ;
                       3, 5, 6, 8, 7 ; }
    shape          = four_node_tet
}
VOLUME_SET( "prisms" ) {
    elements       = { 1, 1, 2, 4, 9, 10, 11 ;
                       2, 3, 4, 6, 12, 13, 14 ;
                       3, 5, 6, 8, 15, 16, 17 ; }
    shape          = six_node_wedge
}
SURFACE_SET( "tetrahedra surfaces" ) {
    surfaces       = { 1, 1, 1, 2, 4 ;
                       2, 2, 3, 4, 6 ;
                       3, 3, 5, 6, 8 ; }
    shape          = three_node_triangle 
    volume_set     = "tetrahedra" 
}
SURFACE_SET( "prism surfaces" ) {
    surfaces       = { 1, 1, 1, 2, 4, 9 ;
                       2, 2, 3, 4, 6, 12 ;
                       3, 3, 5, 6, 8, 15 ; }
    shape          = four_node_quad
    volume_set     = "prisms" 
}
The surface sets can then be referenced in commands that accept surface elements as arguments. For example, the following SIMPLE_BOUNDARY_CONDITION command can be used to define a profiled inlet velocity field that spans tetrahedra and prism elements.
SIMPLE_BOUNDARY_CONDITION("profiled inlet velocity"){
   surface_sets     = {"tetrahedra surfaces","prism surfaces"} 
   type             = inflow
   inflow_type      = average_velocity
   average_velocity = 1.0
}
The surfaces may also be placed in a file, such as tet_surfaces.srf
1      1         1            2               4
2      2         3            4               6
3      3         5            6               8
and read into the SURFACE_SET command:
SURFACE_SET( "tetrahedra surfaces" ) {
   surfaces    = Read("tet_surfaces.srf")
   shape       = three_node_triangle
   volume_set  = "tetrahedra"
}

The volume_set, shape, and surfaces parameters of the SURFACE_SET command are mandatory. shape specifies the shape (topology) of the surface elements in the set. volume_set provides the name of the volume set containing the parent volume element for each surface element. surfaces provides the surface element connectivity. This parameter is a multi-column array. The number of columns depends on the shape of the surface. For three_node_triangle, this parameter has five columns, corresponding to the element number (of the parent volume element), a unique, within this set, surface number, and the three nodes of the element face. For four_node_quad, surfaces has six columns, corresponding to the parent volume element number, a surface number, and the four nodes of the element face. For six_node_triangle, surfaces has eight columns, corresponding to the parent volume element number, a surface number, and the six nodes of the element face. One row per surface must be given. The three, four, or six nodes of the surface may be in any arbitrary order, since they are reordered internally based on the parent volume element definition.