TUFLOW Remapping: Difference between revisions

With the release of TUFLOW 2020, the combination of Quadtree mesh and Sub-grid Sampling (SGS) method has offered a great flexibility tofor build aflood model withbuilding. Now a wide range of mesh sizes.size SGScan samplesbe theapplied digitalin elevationa model (DEM)based aton athe numbergeographic of points within a cellfeature and computing the waterarea surfaceof elevationinterest asin a functionproject. ofEspecially cellwith storedSGS volume. With SGSmethod, cells and faces can be consideredtreated as "'partially wet"', and this means the impact of the sub-grid scale geometry canmay be represented by cells with larger sizes. The example below shows that a Quadtree model with 10/20m cell size (right) can conductconvey water as smoothly as a 2.5/5/10/20m model along athe narrow streamand meandering gully line.<br>

These examples indicate the mesh size sensitivities of a SGS model are significantly reduced, and thus modellers are increasingly using coarser mesh at areas far away from the locationarea of interest. However, this has also create a challenge for how to outputinterpolate water depth output at those coarser cells. The example below shows that even the 10/20m mesh and the 2.5/5/10/20m mesh SGS models produce similar water level, but the depth map output is much 'smoother' in the model with finer meshes. <br>

In TUFLOW, the depth output is interpolated from the depths at the nearest cell centre and cell corners surrounding the output grid. The interpolated depth may not perfectly represent the actual depth, sinceBecause TUFLOW doesn't store the under layingunderlying high resolution DEM values at the moment, the interpolated depth may not perfectly represent the actual depth as illustrated in the figure below. <br>