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JJStobart

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  1. Hi Sam, If you were using just HPC with a fixed grid then i would agree with your above reasons - basically you want to select a grid size to accurately represent the size of the channels you are concerned about and hydraulically significant structures - i.e. those in your areas of interest and all those that route significant flow to and out of said areas. The graph in question in the release notes, you can see that with QPC being used in higher resolution you get a significant increase in routed flow compared to a lower res. In which case when considering grid size of course the higher level of detail the less artificial loss in channels (caused by saw-tooth effects) and less chance of course cells 'trapping water'. Of course when thinking about grid size another limiting factor is the results size and needed memory to run the simulation. The use of QPC allows the user to specify that differing levels of detail in specific areas while having courser elsewhere. The graph really highlights the power of using both QPC and SGS to take advantage of the sub grid elevations to assist in routing flow. Cheers, Joe
  2. Hi Colin, As it currently stands overlapping vzsh are not supported, running tests you will get the outcome as you have found that the 'last read in' vzsh takes precedent and is applied and others ignored so to speak. If you are using classic there may be an option of interest to you using the VG option in a 2d_bc layer. This effectively has been replaced now for the vzsh option as it’s a simpler approach. However, the VG type bc layer allows you to apply change in elevation via a time-series specified within your bc_dbase. This is quite a legacy feature so you will have to refer to previous manuals, there is also a short feed here: https://www.tuflow.com/forum/index.php?/topic/162-variable-geometry-modelling-posted-pre-2007/ If you are using HPC this option unfortunately isn’t available so your options are limited I am sorry to say. I will log your query to our developers however and this will be on a list for future releases. Cheers, Joe
  3. Hi Duck, Just to update, you should be able to apply a xs to a bridge (1d_nwk line). As the bridge length is effectively zero you only apply a single xs: An example of this can be found in one of our example models here: https://wiki.tuflow.com/index.php?title=Example_Models_Home_page The model in question: EG06_1D2D_5m_004.tcf Cheers, Joe
  4. Hi Duck, Cheers for the input Peter, always appreciated. I'll look into this a bit further but I'd assume as when you're modelling a bridge in a full ESTRY network it looks to the xs associated with channels to bring that to the bridge unit as a bridge effectively has a length of zero as discussed above. In that sense, having a bridge unit standalone in the 2D, I would assume it takes your invert levels (so in the case of -99999 the lowest point on your HW table) and applies this as a flat value across the bridge bed and because of this doesn't accept xs data being applied. BB bridges differ from B bridges in that the losses due to flow contraction and expansion, and the occurrence of pressure flow is handled automatically. The only loss coefficients required to be specified are those due to any piers, and the bridge deck when it is submerged and not under pressure flow. Further information on how losses are applied can be found in section 5.7.2.4 of the 2018 TUFLOW manual. Cheers, Joe
  5. Hi there, In short, yes it is possible to connect a 'standalone' bridge in a 1d_nwk file connected to the 2D with SX links. 1d_nwk file with a B/BB type input (for this example i have used a B bridge type). The only attributes needed will be a unique ID, type (B), and then an US/DS inverts set at -99999. (setting the invert levels at -99999 will force tuflow to set both inverts at the lowest point on your HW table, you can enforce invert levels and use the Z flag in your SX line if the user wants this). once you have your 1d_nwk file set up with your CN/SX links snapped to either side you just need to use the 1d_bg file to digitise lines intersecting the the 1d_nwk file. One that links to your HW table and one that links to your LC (losses table) as im using a B bridge type. the only attributes needed here will be the type of each and the source linked to the csv containing the info on the HW and LC values. schematisation of this below/attached: Useful pages with further helpful information: https://wiki.tuflow.com/index.php?title=1D_Bridges https://wiki.tuflow.com/index.php?title=TUFLOW_1D2D_SX_Advice Also as TUFLOW looks at bridges with a length of zero (assuming short structure with little frictional influence) if you have substantially long bridges it might be worth considering changing to a culvert set up. Cheers, Joe
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