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Andrew Chapman

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  1. Hi Phil, Thanks for the reply. Based on the US-FHA reference, Figure 7 (incremental backwater coefficients for piers) includes values of the pier obstruction ratio (J) up to 0.18. I'm looking at a value of around 0.9 for a modern timber paling fence so you could reasonably assume a value of 1.0 through extrapolation to represent the additional form loss caused by such a fence (applied using FLC_below_Obvert for 2d_fcsh). I have searched a few other hydraulic references and can't find anything else for guidance. As you said, calibration data is what we need. Did anything come out of the work in Newcastle? Also, I have some acoustic fences in my model that are impervious to flow. I initially modelled these as 2d_fcsh with a pBlockage of 100 however flow still seems to cross the fence. I have reverted to 2d_zsh which does the job, but I'm confused why the 2d_fcsh didn't work as expected. Regards, Andrew
  2. Hi Phil, I have looked at the reference publication and there's not a lot of explicit modelling advice. I'm modelling some timber paling fences where there is not complete flow blockage. Initially I used the 2d_zsh but there is no allowance for porosity, only complete blockage. So I tried 2d_fcsh to change the flow width of the cell sides where the fence is located, however I find the results aren't as expected. In one case I specified a pBlockage of 95% yet the results viewed in SMS still show a fair amount of flow depth and velocity crossing the fence. What is your preferred approach for fences with partial blockage? Cheers, Andrew
  3. Hi Paul, We've used the QUDM apporach for field inlet capacity and applied it to the model using the Pit Inlet Database. Works fine, although we don't have any field data to verify the accuracy. As described in QUDM, the pressure change coefficient can very significantly but we adoped the default value of Kg = 2.75. Also, we assumed the inlets were never fully drowned as we didn't have time to estimate head loss through each structure. Cheers, Andrew
  4. Hi, I'm testing a proposed flood mitigation pipe and want to maximise inflow from the 2D domain to reach pipe capacity. I want the pipe to control the flow and not the pit channel. Would it be sufficient to simply specify the pit channel with an area larger than the pipe? I realise this can easily be tested in TUFLOW, but am wanting to understand how flow into a circular or rectangular pit is calculated. Regards, Andrew
  5. Hi Bill, I have created a batch file to run TUFLOW_to_GIS. An example of the code is provided below. My problem is that it is not finding the "projection.mif" file even though it exists in the results folder. I renamed the file "header.mif" but that didn't fix the problem. Any ideas why this isn't working? C:\TUFLOW\TUFLOW_Utilities\TUFLOW_to_GIS.exe -mif -t99999 -b C:\TuFlow\Albert Street\results\AS\2d\AS_3m_004_Q10_h.dat Cheers, Andrew
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