Description

At the top of the Boundary Conditions tab (Figure 8.73) is a pull-down to select the Type of boundary condition you wish to apply. Before any changes can be made on this tab, at least one boundary connector (extruding domains) or one boundary node (extruding connectors) must be selected in the Display window. All the available boundary conditions will be described in detail here. The entities to which a particular boundary condition can be applied is shown in parentheses. Once the boundary condition has been changed, use Set Boundary Condition to apply the changes.

  • Adjacent Grid (Structured and Unstructured Domain): Allows the user to specify one or more bounding structured domains which the extrusion will be forced to match as it marches forward. Note that only domains that share a connector with the block's initial face and are non-singular can be picked as a constraining adjacent domain. Use Begin in the Adjacent Grid Selection frame to enter domain selection mode. After making the necessary selections, use End to exit domain selection mode.
  • Adjacent Grid BC
    Use the Adjacent Grid Selection frame to choose domains for the Adjacent Grid boundary condition.
  • Arbitrary Plane (Unstructured Domain): Examines the grid and automatically determines the plane in which each connector lies. Each connector will be held constant within its own plane unless it has already been constrained by another boundary condition.
  • Database Constrained (Structured and Unstructured Domain): Allows the user to specify one or more bounding database surfaces which the extrusion will be forced to match as it marches forward. Use Begin in the Database Surface Selection frame to enter database selection mode. After making the necessary selections, use End to exit database selection mode.
  • DB Constrained BC
    Use the Database Surface Selection frame to choose database surfaces for the Database Constrained BC.
  • Constant X (Connector, Structured and Unstructured Domain): Holds the X coordinate of grid points on the boundary constant during the extrusion.
  • Constant Y (Connector, Structured and Unstructured Domain): Holds the Y coordinate of grid points on the boundary constant during the extrusion.
  • Constant Z (Connector, Structured and Unstructured Domain): Holds the Z coordinate of grid points on the boundary constant during the extrusion.
  • Splay (Connector, Structured Domain): Causes the boundaries of the grid to move outward as the extrusion proceeds. Input the value of the Splay coefficient in the associated text field. Splay can have values between 0.0 and 1.0 where 0.0 is no splay and 1.0 is full splay. The default value is 0.1.
  • Symmetry X (Connector, Structured Domain): Keeps the grid symmetric in the X direction.
  • Symmetry Y (Connector, Structured Domain): Keeps the grid symmetric in the Y direction.
  • Symmetry Z (Connector, Structured Domain): Keeps the grid symmetric in the Z direction.
  • Floating X (Structured and Unstructured Domain): Y and Z values are held constant. Only the X coordinate is allowed to float in advancing k layers.
  • Floating Y (Structured and Unstructured Domain): Z and X values are held constant. Only the Y coordinate is allowed to float in advancing k layers.
  • Floating Z (Structured and Unstructured Domain): X and Y values are held constant. Only the Z coordinate is allowed to float in advancing k layers.

Demonstration

Extrusion Boundary Conditions

Grid Extrusions & Boundary Conditions: What's New?