- Refinement regions whose boundaries are aligned with spectral element grid lines tend to behave better numerically.
- Regions that “look” good – have a uniform/symmetric appearance – tend to behave better numerically.
- Convex regions tend to behave better numerically compared to regions that have concave edges.
- In general, LOWCONN should be used instead of CUBIT.
- Always use some amount of SPRING smoothing.
- When creating a high resolution refined region (e.g., ne240) try to have each halo (successive resolutions) be several cells wide on all sides of the domain.
- When making a small refined region you might want to start with ne60 grid (instead of ne30).
- The In the polygon editor of VRM Editor, the number of vortices vertices can not be increased more than 8. When making a large refined region try using multiple polygons in VRM Editor to get edges that follow the SE grid lines.
- To smooth edges in VRM Editor, adjust lon shift and x-shift by small amounts (0.1 deg).
- If you are having trouble with a grid, e.g. it needs large sub-cycling settings, then there is likely a problem with your grid. In the long run, you are better off iterating with variations/adjustments to your grid to get better performance.
- You may want to save refinement map frequently, because the VRM editor sometimes crashes. When there is a crash, you can restart your work from the saving point.