Tutorial #3: A Remote Tutorial # 2: Simple Editing Initial Conditions:

Editing Boundary Conditions:

Select Edit Boundary Conditions to expose the Boundary Conditions Patch List (see Figure 13). The initial list begins with the 6 'faces' of the logically rectangular grid. This `patch list' is edited in a similar manner as the Material Regions list. Additional 2D and 3D patches of Boundary Conditions may be added to this initial list.




Figure 13: Boundary Conditions Patch List

1. From the list, select the patch with coordinate bounds (1,1,1)-(17,15,1), i.e. the patch of the grid labeled `top face' with z-index =1. The exposed Patch Editor widget (see Figure 14) is used to specify this boundary patch. The Patch Bounds may be edited, or imported from a selected region in the 3D drawing area. The user may select Lock and adjust the index text fields while viewing the patch outline in the Main Draw Window to select the desired patch bounds. As in the Initial Conditions Patch Editor, one may enter a parsable algebraic expression which is used to calculate boundary condition values over the patch.






Figure 14: Boundary Conditions Patch Editor

Either Dirichlet, Neumann, or Robin (Mixed) boundary conditions may be chosen. Mixed boundary conditions require two values (expressions) which must be entered separated by a colon. For example, select Type: Dirichlet  for the boundary condition and enter a Dirichlet boundary condition value of `5-10*z' in the Value text field and select OK.

2. To apply time-varying Dirichlet conditions to a subregion of this or any other existing patch, enter the values and the end time for that value for each entry of the time series into the table (see Figure 15.a).
   
   
3. To view the graph of the time series, select Graph (see Figure 15.b). To dismiss the graph, click within the Graph Window. Select OK when done editing or Cancel, as appropriate.







Figure 15:  Edit Patch Options - a) Time series Table, b) Graph

For new patch, select Add Patch to add a patch after the one currently selected in the list and proceed as above. The boundary conditions are determined by overwriting patches in space-time using the order in which the patches appear in the patch list.

Tutorial #3: A Remote Tutorial # 2: Simple Editing Initial Conditions:

Robert Sharpley
Tue Dec 9 10:30:18 EST 1997