TUFLOW 1D2D Boundary Configuration Guidance: Difference between revisions

The modelled flow rates are shown in the figure below. AsThe canfigure be seendemonstrates, comparable peak flow rates are obtained regardless of the cell size (i.e. cell size convergence is demonstrated). The stability in the 1m cell size case has been improved markedly, though there are still some oscillations at low flows. <br>

2d_bc SX line features are often used to connect 1D structure to the 2D domain if the structure width is greater than one 2D cell wide (e.g. <u>[[Tute_M02_QGIS_1d2d_Link#2d_bc_Link_as_Line_ObjectTutorial_M02 |Tutorial Module02Module 02]]</u>). This configuration not only increases the number of 1D/2D linking cells, it also has the added benefit of defining the 1D/2D boundary cells at the approximate location of the inlet/outlet of the 1D culvert. An additional benefit of this approach is that the "width" of the linking cells remains similar in length and location irrespective of 2D cell size. <br>

Consider setting up the 1D-2D linking shown in Figurethe 1.5figure Thebelow; the HX boundary “HXb1” shown in red is connected at each end to the same 1D node, whereas the remaining HX boundaries shown in purple are connected at each end to different 1D nodes. In the case that the flow is leaving the 2D domain to enter the 1D channel, the boundary is usually stable without energy correction, however for the reverse case, under high flow velocity conditions, the boundary may display instability or recirculation. If this does occur the problem may be remedied via an energy correction, using the command