UG_IO SimSys 2D Input/Output Grids

Input grids for all UG related routines, such as AFLR2, assume a consistent ordering of the connectivity. Input grids for AFLR2 use the optional grid boundary condition and initial normal spacing data if it is included. Output grids from AFLR2 usually include face connectivity and typically don't contain any of the optional boundary edge grid information.

2D INPUT GRID CONNECTIVITY

The node indices for edge and face connectivity must be numbered 1 through Number_of_Nodes. All nodes must be unique in physical space (a given coordinate location may not have two or more different node numbers). Also, each possible node index, 1,2,..,Number_of_Nodes, must correspond to an actual node on the boundary edge grid or planar face grid. Connectivity for faces must be defined using either left- or right-hand rule. Connectivity for boundary edges must be defined using the same ordering on a closed curve.

The node connectivity for boundary edges is ordered as shown below.

where

inode1 = Bnd_Edge_Connectivity[0];
inode2 = Bnd_Edge_Connectivity[1];

Indices for tria faces, itria, are numbered one through Number_of_Trias. Indices for nodes, inode1,..., are numbered one through Number_of_Nodes.

The node connectivity for tria faces is ordered as shown below.

where

inode1 = Tria_Connectivity[0];
inode2 = Tria_Connectivity[1];
inode3 = Tria_Connectivity[2];

Indices for tria faces, itria, are numbered one through Number_of_Trias. Indices for nodes, inode1,..., are numbered one through Number_of_Nodes.

The node connectivity for boundary surface quad faces is ordered as shown below.

where

inode1 = Quad_Connectivity[0];
inode2 = Quad_Connectivity[1];
inode3 = Quad_Connectivity[2];
inode4 = Quad_Connectivity[3];

Indices for quad faces, iquad, are numbered one through Number_of_Quads. Indices for nodes, inode1,..., are numbered one through Number_of_Nodes.

AFLR2 GRID BOUNDARY CONDITION FLAG

In AFLR2 the grid boundary condition flag magnitude identifies special types of boundary edges. If the magnitude is 1 then the boundary edge is a normal edge. If it is 3 then the boundary edge is an embedded or transparent edge (grid domain on both sides). The sign of the grid boundary condition flag controls which boundary edges will have an adjacent boundary-layer or structured-layer type grid. If the grid boundary condition flag is negative then that boundary edge is included in a list of edges for boundary-layer or structured-layer type generation. The sign of the grid boundary condition flag is only used if either the boundary-layer or structured-layer option is selected. The default value for the grid condition flag is -1.

AFLR2 INITIAL NORMAL SPACING

In AFLR2 the initial normal spacing for boundary-layer elements can be specified as part of an input boundary edge grid. If it is specified, then a value must be given for every boundary edge node. Only those values for nodes on an edge with a negative grid boundary condition flag will actually be used. The initial normal spacing is only used if the boundary-layer option is selected. The default value for the initial normal spacing is zero.

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