Quadtree and Sub-Grid Sampling FAQ: Difference between revisions

It is possible that without correct breaklines, SGS model allows a leak over a levee or embankment that model with smaller cell size does not. The more 2d_zsh max/ridges are used the better. A rough estimate of SGS testing has required twice the number of ridge lines compared to a traditional model. This also includes locations where there were no ridges previously. Breakline feature in <u>[[ASC_to_ASC | asc_to_asc utility]]</u> might be useful for creating additional breaklines.

 

SGS isn't a silver bullet that resolves all. If the hydraulic controls aren't adequately defined by the chosen cell resolution the results will vary until the said features are defined by the mesh adequately. Check the gully lines and ridge lines questions above. For a situation where there is little variation in velocity across channel the results might be impressive. In the real world, where there are significant velocity gradients across the channel the modeller might need to use a finer resolution to converge to a solution.