The Design Study Bar is a fully interactive tree-based tool for defining and managing all aspects of the Autodesk Simulation CFD process. The Design Study Bar follows a hierarchical structure that organizes the Autodesk® Simulation CFD process into three fundamental levels: Design Study, Design, and Scenario.
Use the Design Study bar to manage all aspects of the design study including renaming, copying (cloning), and deleting scenarios and designs. We do not recommend performing these tasks through the file system.
For more about the structure of the Design Study
Branches of the Design Study Bar
Keeping accurate records about each scenario is very important, especially when comparing a large number of designs and scenarios. Recording specific conditions, as well as any adjustments and important findings, is key to repeatability and organization of a large project.
A Note file is available for every Design Study. Use this file to record information about the Study that will be useful for future reference.
There are two ways to open the Note dialog from the Note branch:
- Double-click on the Note branch, or...
- Right click on the Note branch, and click Edit.
The Note dialog is a Rich-Text editor.
Your information is automatically saved when the dialog is closed, and can be reviewed anytime the Design Study is open.
A design is a unique geometric model, and is referenced by one or more scenarios. At a minimum, there is one design in every design study. These are the settings in the Design right click menu:
- To activate a design, right click the design, and click Expand. Right click on a scenario within the design, and click Activate. (Note that it is not possible to create a new scenario in a design before first activating the design.)
- Copy a design by clicking Clone.
- Rename: When designs are created, they use a default naming system. Change a design name by selecting Rename. Designs in a Design Study cannot have the same name.
- New scenario: Create a new Scenario that references the geometry of the design. No settings are applied. To create a copy of an existing scenario within a study, right click on the scenario, and select clone.
- Delete: Remove a design from the study. Delete is grayed out if there is only design in the study.
- Save settings as template...: Create a template using the settings in the current design.
- Apply template...: Opens the Template Manager for applying a template to a design. For more about Templates...
NoteA design is locked while any scenario within the design is running. This prevents accidental modification of the geometry during the simulation.
Notes about Cloning
- Cloning copies the design and all scenarios in the design. It is very useful for quickly creating new designs with the Design Study Manager.
- Cloning is the foundation for leveraging the settings of an existing design when creating a new design.
- A design can be cloned before or after scenarios have been run, but not while one is running.
- If a scenario has been run, and the design cloned, no results will be available for visualization in the cloned scenario. The mesh on the scenario will be cloned, however.
- It is possible to continue running a cloned scenario from a saved iteration.
For an example of cloning a design
Use the Geometry branch to perform three essential functions:
1. Set the Analysis Length Units
To set the Units for the design:
- Right click on the Geometry branch, and select Length units.
- Select the desired units from the menu.
- Select whether to change the units or resize the geometry. (See the following note:)
Notes about Length Units
- The default units are meters unless the default was changed in the User Preferences dialog or when launching from CAD.
- For Pro/Engineer geometries, changing the units system only changes the analysis length unit; it does not change any dimensions in the model.
- For geometries originating in other CAD systems, changing the units system will open a dialog that contains a single check-box to Change Units.
- If this box is checked, the dimensions of the geometry are converted to the new units, and the physical sizes are unchanged. For example, if the object was 1 meter long, and units are changed to mm, it will be 1000 mm long. (Same size, different value).
- If this box is unchecked, the geometry will be resized. For example, if the object was 1 meter long, and units are changed to mm, it will become 1 mm long. (Different size, same value.)
- If the geometry is resized (box unchecked) after the units are changed (box checked), the dimensional values are reset to their original values in the selected units system. For example, a 1 m cube is opened into Autodesk Simulation CFD:
- The units are changed from m to mm, and the Change Units box is checked. All sides of the cube are now 1000 mm.
- The units are changed again from mm to in, and the Change Units box is unchecked. All sides of the cube are now 1 in.
- This prevents the geometry from being resized "infinitely," and provides a way to "reset" the geometry back to the original dimensional values.
- If it is necessary to resize the geometry beyond the scope of the Change Units function in Autodesk Simulation CFD, we recommend modifying the geometry in the CAD tool.
Note: All designs in a design study must have the same length units.
- The length units of each new design added to a design study are automatically set to be the same as the other design (or designs) within the study.
- Changing the length units of an individual design causes the length units of every design to be changed as well.
- Length units cannot be changed if any design in the study has a scenario that has been run (results have been computed).
2. Modify the Model with the Geometry Tools
Open the Geometry tools dialog which include the following tools: Edge Merging, Small Object Removal, Void Filling, and External Volume Creation.
To open the Geometry tools dialog:
- Either right click on the Geometry branch, and clickEdit
- Alternatively, click Setup (tab) > Setup Tasks (panel) > Geometry Tools.
NoteGeometry settings made to a design apply to all scenarios within the design.
3. Set the Coordinate system for 2D models.
By default, 2D models run in the Cartesian coordinate system. In some cases, cylindrical geometry is modeled as 2D to take advantage of model axisymmetry.
To change the coordinate system for a 2D model from Cartesian to Axisymmetric:
- Right click on the Geometry branch.
- Select Coordinate System.
- Select either Cartesian 2D, Axisymmetric in X or Axisymmetric in Y.
A scenario is an individual analysis. Every scenario that references a design is based on the same geometry model, but can have different settings (boundary conditions, materials, etc.). At a minimum, every design contains one scenario.
These are the items in the Scenario right click menu:
- Activate: Only one scenario is active at any time in a design study. Open a Scenario and make it available for edit and interaction by clicking Activate from the right mouse button menu. To activate a scenario in a different design: right click on the design, click Expand, then right click on the scenario and click Activate.
- Clone: Copy a scenario by clicking Clone.
- Rename: When scenarios are created, they use a default naming system. Change a scenario name by selecting Rename. It is not possible to have scenarios with the same name in the same design.
- Delete: Remove a scenario from a design. Delete is grayed out if there is only scenario in the design.
- Solve: Opens the Solve quick edit dialog.
- Generate Mesh: Constructs the mesh on the scenario, but does not compute the solution.
If a setting is changed after a scenario is run, the results are no longer current with the model setup. The Warning icon on the Scenario and Results branches indicates the simulation should be run again to capture the effect of the modified settings:
Notes about cloning:
For an example of cloning a scenario
- Cloning copies the scenario within the Design, and is very useful for quickly creating a new scenario that is similar to an existing one. After cloning, you might want to keep most settings while modifying only a few.
- Cloning is the foundation for leveraging the settings of an existing scenario when creating a new scenario.
- A scenario cannot be cloned while running.
- If a scenario has been run before being cloned, no results can be visualized in the cloned scenario. However, the cloned scenario will contain the mesh.
- A cloned scenario can be continued from a saved iteration on the Solve dialog.
The right-click menus vary depending on where they are opened from (Material branch, Material assignment branch, or Part branch). Menu items that need explanation are described:
- Open the Material quick edit dialog with Edit. Select entities by clicking on them before or after clicking Edit.
- To change the environment conditions for all materials, click Edit scenario environment reference....
- To create a new material, click New material....
- Re-assign the default (unassigned) material to all parts by clicking Remove all.
- After clickingSelect all (to select all parts), select to assign or modify material settings.
Material Assignment Branch:
- Click Edit to open the Material quick edit dialog. This automatically selects all parts that are assigned that material.
- To change the environment conditions for a particular material, click Edit material environment reference...
- To remove a part from the analysis, click Suppress. This causes the part not to be meshed.
- Control the appearance of all parts assigned a material by clicking either Shaded, Transparent, or Outline.
- Modify a material setting on a part by clicking Edit. This will open the Material quick edit dialog with the part selected.
- To unassign a material, click Remove. The part will be placed into the "Unassigned" branch.
- Prevent a part from being in the analysis by clicking Suppress. This will cause the part to not be meshed.
- Control the appearance of all parts assigned a material by clicking either Shaded, Transparent, or Outline.
- To create a rule based on a material assignment, click an option from the Create rules menu.
Boundary Conditions and Initial Conditions
The Boundary Condition branch is organized by condition, with each condition or combination of conditions listed as separate branches. Entities that are assigned each condition are sub-branches.
The right-click menus vary depending on where they are opened from (Boundary Conditions branch, Condition assignment branch, or Entity branch). Menu items that need explanation are described:
Boundary Conditions Branch:
- Open the Boundary Condition quick edit dialog with Edit. Select entities by clicking on them before or after clicking Edit.
- To create a new boundary condition, click New BC... After creating the boundary condition, drag it to the part or surface to assign it.
- Delete all applied boundary conditions by clicking Remove all.
Condition Assignment Branch:
- Open the Boundary Condition quick edit dialog with Edit. All entities listed below a selected condition branch will be automatically selected.
- Modify a boundary condition on an entity by clicking Edit. This opens the Boundary Condition quick edit dialog with the part or surface selected.
- To create a summary item using a surface or part that is assigned a boundary condition, click Create summary item.
- Control the appearance of an entity by clicking either Shaded, Transparent, or Outline.
Use the Meshing branch to manage mesh sizes and to access the Mesh Sizes dialog.
When Automatic sizing is invoked, the word "auto" appears on the Mesh Size branch. No geometry-specific mesh settings are given:
- Open the Mesh Sizes dialog by clicking Edit. (Click the Automatic Size button on the Mesh dialog to apply mesh sizes.)
- Generate the mesh with Generate mesh. See below for more about Generate mesh.
- Each step in the mesh definition history is listed as a separate branch. This provides visibility to how a mesh was defined as well as the ability to roll back the mesh to an earlier state. To rebuild the mesh definition after making a change, click Rebuild mesh definition.
When Manual sizing is used, each size is listed on a separate branch. Entity types (volumes, surfaces, and edges) are sub-branches that in turn contain individual entities:
- To modify the mesh size of a particular entity, right click on its label, and click Edit. This opens the Manual Mesh sizing dialog.
- To modify the appearance of an entity, select Shaded, Transparent, or Outline.
- To modify the mesh size of every entity with a particular mesh size, right click the entity type Volumes, Surfaces, or Edges) under the current size, and click Edit.
NoteIf Automatic Sizing is invoked, and the mesh type is changed to Manual sizing, the mesh size on each surface is listed as a separate branch.
Notes on Generate mesh
- A very useful technique for creating an efficient mesh is to examine it carefully prior to running the analysis.
- For large models or models with dense mesh distributions, this can be a lengthy process. It is always a good idea to check the Approximate element count on the Mesh dialog prior to previewing the mesh.
- This provides an opportunity to check for over-meshed regions and to ensure that areas of potentially high gradients are not under-meshed.
- After clicking Generate mesh, the mesh is generated, and can be examined in the Results task. If the mesh is acceptable, it does not have to be generated again to run the analysis.
The Motion branch is organized so that each applied motion condition is listed as a separate branch, with a single entity as its sub-branch. Entities that are assigned the same motion condition are listed in separate motion sub-branches.
- To open the Motion quick edit dialog, right click on the Motion branch, and click Edit.
- To modify an applied motion condition, right click on the entity branch, and click Edit.
Create, add to, combine, and remove groups using the Groups branch.
- To create a new group, right click on Groups, and select Create new group.
- To combine groups (containing the same entity type), right click on a group branch, and click Add to existing group.
- To add an entity to a different group, right click on it (shown), and select Add to existing group.
For more about managing groups
Analysis settings are listed under the Solver branch.
- To open the Solve dialog, right click on the Solve branch, and click Edit....
- To modify a Solver setting, right click on the setting, and click Edit...
Additionally, the Flag Manager is accessible from Solve. Right click and select Flag Manager. Use the Flag Manager to enable additional settings that control the user interface appearance and solver behavior.
For more about the Solve dialog
When geometry is changed and a design updated, certain settings from the original may not be assigned to the new geometry if components were removed or relocated.
For example, a printed circuit board containing several chips and heat sinks is part of an electronic module. Heat generation boundary conditions and materials are applied to the chips.
In a design iteration, one of the chips is removed from the CAD model. When the design is updated, the material and boundary conditions on the chip cannot be applied to the model.
Such settings will appear on the Design Study bar as an orphan branch with the Lost icon:
To assign a lost setting to a component:
- Drag it the model entity in the Graphics window.
- Alternatively, drag it onto an entity listed in the Design Study bar.
If the setting cannot be applied back to the model because the part was not replaced, delete it by right-clicking on the setting, and click Delete.
NoteThe scenario cannot be run if any lost settings are shown in the Design Study bar. You should either assign or delete all lost settings.
For an example of fixing a lost setting
Design Study Bar Placement
To move the Design Study bar:
- Left click in the title region of the dialog.
- While holding the mouse button, drag the window to the desired location.
To re-dock the Design Study bar:
- Drag the bar near the desired edge of the User Interface.
- Double click with left mouse button in the title region.
NoteDesign Study bar placement persists from one session to the next.