Since its introduction, Automatic Mesh Sizing has greatly simplified the modeling process. Automatic Mesh Sizing defines a mesh that is optimized for the model and accurately represents every detail of the geometry.
A good representation of the geometry is only one requirement for a high fidelity solution. For example, the flow on a simple model with a uniform mesh can contain significant gradients. The results on the coarse mesh may not be highly accurate, but they do indicate flow trends. These trends can be used to identify where the elements should be concentrated to improve solution accuracy.
Mesh Adaptation uses solution results to progressively improve the mesh definition. The simulation is run several times. Each time the results in the previous cycle are used to improve the mesh in the next cycle. The result is a mesh that is optimized for the particular simulation. The mesh is finer for high gradient regions, and coarser elsewhere.
When Mesh Adaptation is enabled, the following occurs:
- A baseline scenario is run to completion.
- The mesh is changed (often refined) based on velocity, pressure, and temperature (if available). The simulation is run to completion.
- The process repeats for each Adaptation cycle.
The result is an intelligently refined mesh that is tuned for the flow and temperature results fields.
Using Mesh Adaptation
To enable Adaptation, open the Solve dialog, and click the Adaptation tab.
The Adaptation dialog contains several Mesh Adaptation controls. The following items are the most commonly used. They define essential behavior including the number of adaptive cycles and if the results from intermediate cycles are saved:
To enable Mesh Adaptation, check Enable Adaptation.
Cycles to Run
By default, three adaptation cycles are run. To run a different number, change Cycles to Run. Note that the total number of scenarios includes a baseline plus the specified number of cycles.
If Adaptation is enabled before running a simulation, an initial baseline is run in addition to the specified number of cycles:
Total cycles = Cycles to Run + 1
If Adaptation is enabled after running a simulation, only the prescribed number of Cycles to Run are run. The existing scenario is used as the baseline.
To save each intermediate mesh, enable Save Cycles. Each time a scenario finishes, it is automatically cloned, and the cycle number is appended to the base scenario name. For example:
- At the beginning of the process, the default scenario name is Scenario 1.
- Scenario 1 is run to completion and cloned. The cloned scenario is named Scenario 1- Mesh 1.
- The mesh on Scenario 1is adapted to the results, and run to completion.
- Scenario 1 is cloned again. The cloned scenario is named Scenario 1 - Mesh 2.
- This continues for the specified number of cycles.
- At the end, Scenario 1 contains the final mesh, and the intermediate cycles are saved in Scenario 1 - Mesh 1, Scenario 1 - Mesh 2, and Scenario 1 - Mesh 3, etc.
NoteThroughout the process, Scenario 1 is always the active scenario. At the end, Scenario 1 contains the final mesh. The intermediate meshes are contained in the scenarios with "Mesh" appended to their names.
Because each mesh cycle is saved to a unique scenario, it is easy to use the Design Review Center and the Decision Center to study the effect of mesh sensitivity and to determine mesh dependency.
If Save Cycles is disabled, only the final mesh and results are saved in the design study. The intermediate adaptation cycles are discarded.
By default, Mesh Adaptation only refines the mesh. To allow it to make the mesh coarser (thus preventing the mesh from growing too large), enable Allow Coarsening.
Mesh Adaptation does not support the following simulation types or settings:
- Transient simulations (including Motion and Rotating)
- Quick Convection (including both Forced and Natural/Free)
- 2D models
- Surface parts
- Extruded meshes
- Models launched from Pro/Engineer with the Mechanica method.
- The following material types:
- Distributed Resistance
- Internal Fan
- Centrifugal Pump /Blower
- Check valve
- Rotating Region
- Compact Thermal Model (CTM)
- Themoelectric device (TEC)
- LED device
- You should define an initial mesh that follows standard mesh best practices. This helps to arrive at the mesh independent solution more efficiently.
- Because Mesh Adaptation runs several cycles to arrive at the final mesh, the complete analysis can take longer to run than a scenario run without Adaptation. Additionally, the overall element count can grow considerably larger than the original mesh. Be careful with complex models that are initially large, as they will take much longer to run. The benefit, however, is that the resultant solution is mesh independent.
- When you click Stopon the Solve dialog, the current cycle stops, and no further adaptation cycles are run. To run additional adaptation cycles after the simulation has stopped, click Enable Adaptation on the Adaptation tab. The solver runs the prescribed number of Cycles to Run.
- Note that Adaptive Meshing works for both Automatic Mesh Sizing and Manual Mesh Sizing.
- The folder that contains the scenario must exist in the Design Study folder structure. Results must exist within the scenario folder to apply mesh adaptation to a scenario that has been run.
NoteWhen a simulation is continued from iteration 0, all saved results are deleted and Adaptation is disabled. To adapt the mesh for the current design, first run the current scenario with Adaptation disabled. Upon completion, enable Adaptation, and continue the simulation. The completed scenario becomes the baseline for subsequent mesh adaptation cycles.
- Every cycle runs either the number of specified iterations or until convergence is detected by Automatic Convergence Assessment. Because finer meshes typically require more iterations to converge, it is good practice to specify at least 300 iterations on the Solve dialog. This ensures that every mesh in the process can attain convergence.
For an Example model showing how to use Mesh Adaptation...