TUFLOW Stability Troubleshooting: Difference between revisions
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** Set an initial water level so the model doesn't start completely dry. This can be done globally with <font color="blue"><tt>Set IWL </tt></font> command or locally with 2d_iwl polygon.
==How can I stabilise 1D features and their 1D/2D boundaries?==
=== 1D open channels including connected bridges and culverts ===
* Split or merge open channel sections - the general advice is to have the length of open channels about 3 to 5 times of their width. Merging very short channels will provide sufficient storage. Splitting long channels into shorter ones with more 1D nodes might smooth the water level slope and the simulated flow rate can become more stable.
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=== Notes for all features===
* Use the latest available TUFLOW release.
* Use Sub-Grid Sampling (SGS) if using HPC. This allows for more accurate calculations of flow and water level that transitions into the 1D features
* Double precision might be used, however this would cause models running slower and other measures are recommended to try first.
* Lower 1D timestep can be sensitivity tested, however the timestep should still remain within reasonable bounds. If the 1D timestep is required to be very small for stability reasons, usually other measures can be taken to improve the stability and consequently run time of the model.
* If using TUFLOW Classic, 2D timestep should be between 1/5 and 1/2 of the cell size in metres. Lowering 2D timestep within this range might be beneficial for stabilising 1D/2D links.
== My model reports very high mass balance error at the beginning, then it lowers. Is it unhealthy? ==
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