TUFLOW 2D Cell Size Selection: Difference between revisions
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: ''Details of the model schematisation process including resolution aspects are described in Chapter 6. Chapter 7 also highlights the importance of grid/mesh resolutions in achieving manageable run times to maximise calibration outcomes. Table 10-2 (below) provides guidance on levels of model resolution that may be appropriate in certain typical situations.''
{| class="wikitable "
| '''Modelling Case''' || '''Typical 2D Cell Resolution'''
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| '''Flow in Channel''' || In order to adequately resolve flow in a channel it is desirable to provide at least 5 grid/mesh elements laterally across the channel
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| '''Urban Overland''' || Most urban flood models employ grid/mesh resolutions of 2m to 5m.
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| '''Flow in Floodplain''' || Rural floodplain models typically employ grid/mesh resolutions of 10m and 50m (although resolutions up to 200m have been used) depending on the size of the are to be analysed, the characteristics/dimensions of the floodplain and the desired level of output detail.
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| '''Lakes and Estuaries''' || these situations often include areas of open water where less detail is required than along the water body boundary. Such situations are well suited to a flexible mesh rather than fixed grid based model as the mesh is able to incorporate a change of resolution across the model domain. element resolutions for these models can span the full range as described above depending on project requirements.
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| '''Flow Over and Embankment''' || Embankments effectively act as weirs in the floodplain context. Many 2D modelling packages have automatic or manually activated corrections that compensate for the error in head loss typically associated with modelling broad-crested weir flow with a 2D scheme. For practical purposes, a single 2D element is generally adequate to represent the impact of a levee, road or railway embankment. The resolution of these elements is generally not a significant limitation on the schematisation of most domains.
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This Wiki page uses two test cases to discuss this topic. Quantitative results are presented demonstrating how and when cell size has a tangible impact on model results.
= Test Case 1 =
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