SMS:Curvilinear Grid Module

The curvilinear grid module contains tools used to work with curvilinear grid data. Curvilinear grids consist of nodes that are grouped together to form cells. These nodes and cells define the computational domain of the numerical model. In addition to nodes and cells, a curvilinear grid may store additional information such as material values assigned to elements and boundary conditions assigned to nodes. In general, this additional information is used as input data for the numerical model.

Nodes

Nodes are the basic building blocks of cells in a curvilinear grid. Nodes store elevation and other dataset values. Nodes can also be used for building nodestrings and assigning boundary conditions. The density of nodes helps determine the quality of solution data and can be important to model stability.

Cells

Cells are used to describe the area to be modeled. Cells are formed by joining exactly four nodes. No more than four cells may join at a single node. If four cells join at a single node, the node cannot be a boundary node. Cells are identified by a unique i, j index.

Delete Cells

1. Click on the Select Element tool for curvilinear grids or Vtk Meshes.
2. Select the cells to be deleted.
3. Right-click on the selected cell and select Delete or hit the DELETE key.
4. For curvilinear, the Delete will fail and error message will be displayed if the grid would become invalid if deletion occurred.

Add Cells

Cells can only be added to an existing Curvilinear grid.

1. Click on the Create Element tool for cuvilinear grids.
2. Click and hold on any element on the edge of the grid and drag the displayed arrow across the boundary edge, then release. A new element will be created.

Nodestrings

A collection of nodes can be formed into a nodestring. Nodestrings are most commonly used to assign boundary conditions such as a flowrate or water-surface elevation. Nodestrings can also be used for mesh renumbering, forcing break lines, and boundary smoothing. Finally, a nodestring can store attributes pertinent to a location such as the total flow nodestring.

Delete Nodes (Vtk Mesh only)

1. Click on the Select Node tool for Vtk mesh.
2. Select the nodes to be deleted.
3. Right-click on the selected nodes and select Delete or hit the DELETE key.

Merging Two Curvilinear Grids

To merge two curvilinear grids there must be at least one segment that is common (shared) between the two grids.

To do a merge:

• Hold down the CTRL key and select two curvilinear grids from the tree item.
• Right click and select Merge Curvilinear Grids.

A new curvilinear grid is created from the two selected grids.

Models

The curvilinear grid module currently includes interfaces for:

• LTFATE

Tools

See Curvilinear Grid Module Tools for more information.

Menus

When one or more active nodestrings have been created, and the Select Nodestrings tool is selected, a set of menu's becomes available by right-clicking on the mouse. The menu items operate on the active nodestrings:

• Delete Selected – Deletes the selected nodestrings.
• Merge Selected – Will merge two or more selected nodestrings to form a single nodestring. Nodestrings must share the same endpoints to be merged.
• Clear Selections – Unselect all of the selected nodestrings.
• Select All – Selects all nodestrings.

Display Options

See Curvilinear Grid Display Options for more information.

Related Topics

• Curvilinear Grid Display Options
• SMS Modules