FMA Challenge 1 (1D-2D linked): Difference between revisions

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To run the model with varying cell sizes from a single TCF, the use of scenarios has been implemented. The scenario here either '10ft' or '15ft' can be entered in the batch file using the -s command. If the -s command is not used, the model will assume a default model scenario of 10ft as specified by the line <font color="blue"><tt>Model Scenario </tt></font> <font color="red"><tt>==</tt></font> <tt> 10ft. </tt><br>
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The cell size, 2D timestep and log output frequency are all set usingexternally to the TUFLOWtcf Readusing Filean Commandexternal asread followsfile:
 
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WithinWhen the model is initialised the scenario value is passed to the *.trd file and the variables 2D_CELL_SIZE, 2D_Timestep and LogInt variables are set asusing scenariothe dependent'Set variablesVariable' command. This results in scenario dependant values of 2D_CELL_SIZE, 2D_Timestep and LogInt
 
When the model is initialised these variable values are inserted within the tcf and tgc file using the << >> syntax. i.e. For the 10ft scenario, <<2D_Timestep>> in the tcf is replaced with the value 10 as defined in the trd file.
Using the << >> syntax, the values set within the trf are substituted. For example for the -s 10ft scenario:
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Upon examination of the results, the flood extents varied by unexpected amounts between different resolutions. For example, the 10ft grid scenario (provided as part of the ftp download) produces a more extensive flood extent, even though the profile down the 1D channel is almost identical to the 15ft case. The extended flooding is the result of very shallow flow (less than 0.01ft deep) over large flat (horizontal) areas caused by the use of contours to create the DEM as discussed above. Due to the slightly coarser resolution the 15ft grid does not let water on to some of these flats, and they remain dry. Should an accurate DEM be made available for this Challenge, the flood extents are likely to be very different and much more consistent between different grid resolutions!