TUFLOW General Discussion: Difference between revisions
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* The 2020 TUFLOW release offers sub-grid topography sampling to process all elevations within the cell into a depth/volume relationship for its calculations. This approach ensures much more accurate water depth estimations at pit inlets, even if the 2D cell resolution is much larger than the geometry of the drain at the inlet. This in turn translates to more accurate representation of the pit inflow, and as such flow through the entire pipe network. No other 1D/2D stormwater drainage modelling software offers this functionality. The new Quadtree functionality also allows the user to model key flowpaths, such as road drains, in high resolution.
* The 2D overland approach used by TUFLOW ensures any above ground inundation is defined by the model topography. This approach avoids any engineering judgement flow path definition mistakes which the 1D overland software suffer from.<br>
==Can TUFLOW model flows in steep slopes accurately?==
The Saint-Venant equations are commonly shown in 1D form and represent the conservation of volume and momentum along a flow channel (also known as the dynamic wave equations). When extended to two dimensions, the Saint-Venant equations become what is commonly called the “Full shallow water equations”. These equations are physically correct and comprehensive, but do require a eddy-viscosity closure term for stability when higher-order interpolation schemes are used. This applies to both finite-difference and finite-volume form. When solved correctly, the solution accurately reproduces both subcritical and supercritical flow, as well as the location of transitions between the two including, importantly, locations of hydraulic jumps. Therefore the equations remain perfectly valid on steep ground. As a further note, we recommend using the sub-grid-sampling (SGS) feature for direct rainfall models as this improves the hydraulic response of small flow channels that are not well defined at the model cell size.
Empirical validation of TUFLOW up to a slope of approximately 10% is documented in Huxley (2005), refer to Figure 33 and Figure 39: <u>[https://www.tuflow.com/media/4989/2004-tuflow-testing-and-validation-huxley.pdf TUFLOW Validation and Testing, Chris Huxley Thesis.doc]</u>
The following link documents a <u>[https://www.tuflow.com/media/5015/2016-tuflow-gpu-best-practice-advice-for-hydrologic-and-hydraulic-model-simulations-huxley-et-al-hwrs-nz.pdf real world TUFLOW calibration example]</u> for a case study location where the average catchment slope is over 15% in the upper half of the catchment.
This original package of work was completed in 2015 using TUFLOW’s traditional cell centre/side zpt topography processing approach. The model was rerun in 2020 using the new SGS topography sampling feature for the <u>[https://www.tuflow.com/library/webinars/#feb2021_direct_rainfall Direct Rainfall webinar]</u>.
Collectively, these simulations demonstrate that TUFLOW’s solution works well in steep catchments. They also highlight the benefits of using SGS.
==Can TUFLOW model non-water liquids?==
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