Switch numerics presets

Move through the tested presets before constructing detailed numerical overrides.

Move down the preset chain

Keep the physical model and mesh unchanged, then try:

1. fast → balanced;
2. balanced → stable; or
3. if already on stable, diagnose the affected equation before overriding it.

Set the selected preset directly in numerics, for example:

"numerics": "balanced"

For the first comparison, remove existing per-equation overrides so the complete tested preset is applied. Compare residual histories, *_linear_iterations, monitored values, and total runtime with the previous run.

The names do not guarantee runtime order. Stronger preconditioning and calmer SIMPLE updates can make balanced or stable faster than fast for a difficult case.

If stable still fails, continue with Use stronger numerical relaxation and Change preconditioning.

See also

• Numerics presets compares what each preset changes.
• Diagnose an instability shows how to identify the equation requiring further work.