TUFLOW 2D2D BC Advice: Difference between revisions
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<li> Flow is transferred between both domains via a series of hidden 1D nodes. The location of the hidden 1D nodes requires consideration. TUFLOW creates these at each vertex along the 2d_bc "2D" link line and also at a regular interval, as defined by the “d” attribute. The hidden 1D nodes act as storage that convey the water from one 2D domain to the other. The water levels along the 2d_bc 2D link line are linearly interpolated using the water levels in the hidden 1D nodes. If in reality the water level profile is not close to linear between vertices, strange flow patterns may occur which can lead to model instability. As such, appropriate resolution of the hidden 1D nodes is an important feature of multiple 2D domain models. <br><br>
The TCF command <font color="blue"><tt>Reveal 1D Nodes </tt></font><font color="red"><tt>== </tt></font> <tt> ON </tt> can be used to view the hidden 1D nodes. The hidden nodes will be written to the [[TUFLOW_Check_Files | nwk_N_check]] layer. The 2D link can also be reviewed using the [[TUFLOW_Check_Files | 2d_to_2d_check ]] layer
[[File: 2D2D_Guidance_003.JPG |400px]] <br><br>
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[[File: 2D2D_Guidance_004.JPG |400px]]<br>
* The 2d_bc “2D” link line can be orientated in any direction within floodplain areas with low velocity (<0.5m/s). The 2d_bc “2D” link line “d” attribute should be used in this situation. This is discussed in the following section. <br>
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2d_bc “2D” link line vertices are best located on ridges or embankments, including features that become inundated and drowned out during a simulation.<br>
* In regions of moderate to high velocity (>0.5m/s), manual vertex placement on the river banks and natural ridges in addition to a “d” value of 0 is common. Using a “d” value of 0 will create a hidden 1D node at each vertex along the 2d_bc “2D” link line. No intermediate hidden 1D nodes will be created.<br>
[[File: 2D2D_Guidance_007.JPG |400px]]<br>
* Model results are less sensitive to the hidden 1D node placement in regions of low velocity (<0.5m/s). Automated placement by using a “d” values greater than 0 is common in this situation. The selected value should be no less than three times the size of the larger cell resolution associated with the 2D/2D boundary. For example, if the model uses a 2.5m and 5m resolution, the “d” attribute should be set no smaller than 15m.<br>
[[File: 2D2D_Guidance_006.JPG |400px]]<br>
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