HPC FAQ: Difference between revisions
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* General improvements and fine-tuning of the solution scheme, especially for the more complex hydraulic physical terms and situations such as: sub-grid turbulence representation; treatment of shocks (e.g. hydraulic jumps); and transitioning between sub-critical and super-critical flow on steep slopes.
* Some new functionality can cause a significant change in results. For example, Sub-Grid Sampling (SGS) applied to an existing model that used a too coarse cell resolution in high flow areas of highly variable topography (relative to the 2D cell size). SGS will greatly improve the model's ability to convey water accurately in these situations with vastly improved results. Another example is the new default sub-grid turbulence scheme in the 2020 release of TUFLOW HPC that is cell size independent and allows modellers to use cell sizes much smaller than the depth across all scales from flume to large rivers.
* Changes to the default settings and values, e.g. different default eddy viscosity formulation and/or coefficients; improved data pre-processing approaches such as sampling materials on cell mid-sides instead of cell centres. For backward compatibility the “Defaults ==” command is available to run old models on new releases to replicate past results (note, sometimes full backward compatibility
* New features that use GIS attributes previously reserved (i.e. unused). If these attributes were not populated with the recommended “reserved” value (usually 0 or blank), then they can cause unpredictable results in later releases.
* Bug fixes noting that most bug fixes are input/output related and rarely affect the model's hydraulic calculations.
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