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About Mitch3007

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  1. Good question and thanks eirianc and peteraylett for the discussion above, It may not be directly relevant to your specific problem, but I've seen issues like this when applying a large number of SA polygons using the Read GIS SA RF == or Read GIS SA ALL == commands which, can often be caused by one large SA polygon. For example, imagine if you had a model with the following setup: Total of 3000 SA or SA RF polygons. One polygon contains 10,000 2D cells. All remaining 2999 polygons are of equal size and contain only 500 2D cells. At model startup, when TUFLOW allocates its boundary memory it's calculated based on the total number of polygons x the number of cells in the largest polygon. i.e. in this example case, 3000 polygons x 10,000 cells worth of memory = 30,000,000 cells that are allocated. So, if you were to split your largest boundary polygon into a series of smaller ones, you can immediately save a fair chuck of memory as follows: Total of 3000 SA or SA RF polygons. Four polygons containing 2,500 2D cells. All remaining 2996 polygons are of equal size and contain only 500 2D cells. i.e. 3000 polygons x 2,500 cells worth of memory = 7,500,000 cells that are allocated. And so on. It's likely that in future releases of TUFLOW we'll throw a warning or check when this behavior occurs so you can make some mods to amend your polygons. Please let me know if you had any further thoughts or queries about the above. Cheers, Mitch.
  2. Thanks Chris, The new features look pretty nice. With the new AR&R requirements I can see the need to run models over multiple computers becoming increasingly relevant and TRIM really seems to help you get a nice little cluster working. Cheers, Mitch.
  3. Hi lcements, Thanks for posting this query. Please see below some comments. If anyone else out there has some new literature on this topic we'd love to hear about it. - How would I best represent a trash screen on the upstream face of a circular culvert? There is some guidance on form losses provided in the previous thread below. - Is it best to account for bends along a culverted length using increased Mannings or a form loss coefficient? You are best to apply bend or drop losses using the Form_Loss attribute of the 1d_nwk layer. This applies the energy loss appropriately for a 'minor' loss using K* V2/2g. You can also use the pBlockage attribute in your 1d_nwk if you believe there will be deposition of debris on the inlet during a flood event. AR&R provides some guiding information on debris blockage here: - What are appropriate form loss values? The loss values will depend very much on the structure and configuration. As described above the Queensland Urban Drainage Manual may provide some guidance. There is also the Concrete Pipe Association of Australasia's Design Manual which is a great document: There is also a range of documents published by the US Federal Highways Culvert Design Manual: which maybe of interest. Hope this helps. Other posts very welcome!!! Cheers Mitch.
  4. Dear TUFLOW Users, Tutorial Model 8 - Direct Rainfall is now online and available for download. This module includes examples on the powerful depth-varying roughness feature in TUFLOW, hyetograph input methods, mass conservation considerations and also the differing approaches required when presenting and reviewing rainfall on grid results. Tutorial Model 8 forms part of a larger series of free tutorial models that users can download and run without a TUFLOW license. They are great for beginners or even those looking to use the latest modelling techniques. Follow these links to get started on the tutorial: (Tutorial Wiki) (Model and Data) Should you have any further queries please don't hesitate to send us an email at Regards, The TUFLOW Team.
  5. Dear TUFLOW users, Brisbane All Brisbane training and workshops sessions are now full. A second set of sessions is now being considered, so if you are interested, please contact ASAP. Melbourne and Sydney Places remain for Melbourne and Sydney training and workshop sessions, however these are filling quickly. To register, or for further information, please read and fill out the registration form and email to We are coming to Perth!!! We are very happy to announce that we will be travelling to Perth in early June (dates to be finalised). If you’re interested in attending, please let us know via email @ We look forward to seeing you there! Kind regards, The TUFLOW Team.
  6. Q: Does TUFLOW work in Windows 10 A: Yes, we have tested TUFLOW using the latest version of the CodeMeter Runtime installed (we used version 5.22a) and had no issues running TUFLOW. If you have a different experience, please contact us at
  7. Hi All, If you haven’t checked it out before the Runme plugin for Notepad++ is pretty handy for running batch files. It will also allow you to open a windows explorer window in the file location directory, which is nice. You can access install and access it through the Notepad++ ‘Plugin Manager’.
  8. Hi Melodea, There are a few things that may be happening. Can you please send me through a few levels to help pinpoint what the problem may be: What is the 2D cell ZC level at one of the pits where you are getting no flow?What is the QH relationship you are using for that particular pit?What are you specifying for your pit upstream and downstream invert levels?What are you using in theConn_2D attribute of your 1d_nwk or 1d_nwke file at the pit?What is the pipe invert level at the upstream end of the downstream pipe?When the pipes are running full, what is the water level in the _TS output file both at the pit and at the upstream end of the downstream pipe?If the hydraulic grade line is close to surcharging into 2D, this may result in zero or even reverse flow. Please let me know the above. If it's easier for you, I might get you to send it through to I can then post it back up onto the forum. Kind regards, Mitch.
  9. Hi Henry, I have recently posted on the application of CFW and FLC in GPU models that may help you out: Although you are trying to model a 5 m bridge in a 15 m cell size, with careful application of either CFW or FLC values you should be able to represent energy losses through the structure. As per the provided link, to understand what sort of losses you might expect through your bridge structure, we recommend cross checking your TUFLOW modelled losses with other methods where possible. Kind regards, Mitch.
  10. Question: I am currently running a GPU model and I am wanting to apply a constriction to represent pier losses from a bridge. My understanding is that within the GPU I can only run a 2d_FLC file which just reads one GIS field for the constriction. I have calculated the constrictions I wish to apply however I am having difficulty finding out how it will be applied within the model. If you could please assist me with the following questions it would be very helpful. -Is the constriction applied to the centre of the cell or at the outer edges. -When applying the constriction do I apply it per m or by per cell (by using a negative value such as the layered flow constrictions in CPU) similar to what occurs in the CPU flow constrictions. Or do I simply apply the full constriction to the cell centre, if I simply want the constriction to apply to 1 grid cell. Is the same process used for the Cell Width Factors? Answer: Within the GPU solver, only the cell centre values are available and used. You can check the FLC or CFW applied to each cell by reviewing the 2d_grd check file. More info is available here: Regarding how the FLC is applied: · You provide the loss value that will be applied to the cell centre/s. It is essentially applied as a minor loss based on the velocity head of that cell centre. FLC * (V^2/2g) · If you use a polygon, all the cells centres within the polygon will be selected and the loss applied. · You can also use a line that will allow you to select a small row of cells based on the ‘crosshair’ principle. · Using the Read GIS FLC == command there is no m by m application of losses that you see when using flow constrictions (which notably are not available in the GPU yet). i.e. you directly apply the loss coefficient to each cell of interest. Regarding how the CFW is applied: · The Read GIS CFW == command is applied in a similar way but acts to reduce the available cross sectional area of the cell. For example, a value of 0.9 will reduce the cell to 90% of full capacity. This factor is applied to all depths of flow through the cell/s. Whenever using these approaches we recommend cross checking the losses through your structure with other model outputs such as HECRAS or with reference to Bridge Design Documents such as Bradley: y Leon/Documentación Técnica/Hydraulics of Bridge Waterways (1978).pdf to assess the sensitivity of your assumed loss approach. Another good post detailing FLCs can be seen here: Regards, The TUFLOW Team.
  11. Hi WQ, We have a technical document on our website that looks at a range of pier modelling methods that might help: It will give you a feeling for the sensitivity of differing methods but 20-30 mm is not unusual. If the bridge is critical, it is probably worth setting up a HECRAS model (or equivalent) to cross check your losses through the structure against the differing FSCH you are using. Hope this helps, Kind regards, Mitch.
  12. Hi TUFLOWers, We hope you have survived the dash to end of financial year . We frequently get asked, "What is the minimum or recommended hardware to use for TUFLOW modelling". This is always a tricky question, as the answer depends on the type and size of the models you are going to be running! For a small model, TUFLOW should run on any modern PC or laptop that is capable of running Windows XP or later. However, for large models there may be requirements for a hefty computer running a 64 bit version of Windows.To assist you, we have prepared a new Wiki page and download so that you can compare run performance on a range of computers and also your own, including both CPU and GPU (if you have one). For more details please refer to: Regards, the TUFLOW Team.
  13. Hi TUFLOW Users, To improve model stability at 2D “H” boundaries or links (eg. HT, HS, HX, HQ, QT, 2D) that exhibit oscillations, you can include the term “BOUNDARY VISCOSITY FACTOR == ” in your TCF file (Build 2013-12-AC or later). This sets the factor to adjust the eddy viscosity coefficient at water level boundaries. Note that 2D QT boundaries and 2D/2D links utilise HX links, and are therefore considered 2D “H” boundaries/links. Prior to Build 2013-12-AC the eddy viscosity term was not applied at “H” boundaries/links. The term was included for the 2013-12-AC build as it was found to provide improved stability in the case of 2D/2D multiple 2D domain links, along with other improvements to 2D/2D linking. Therefore, for multiple 2D domain models from 2013-12-AC onwards the default factor is set to one as one of the enhancements in the new “Link 2D2D Approach == METHOD D”. To maintain backward compatibility for single 2D domain models the factor is set to zero (i.e. no boundary viscosity term) for the 2013-12 builds. For the 2015 release, the default factor will be a value of one whether single or multiple 2D domains as this is the mathematically correct approach. Note that whether the factor is set to zero or one there will be little or no measurable difference in results if the model is running healthily. However, for “H” boundaries/links that experience oscillations or instabilities, using a “BOUNDARY VISCOSITY FACTOR ==” of one or higher may provide improved performance. Note that other checks such as ensuring the boundary is appropriately set up are more important than simple applying an increased “BOUNDARY VISCOSITY FACTOR ==”. For example, the most common set up problem for 2D QT and HT boundaries are that they are not digitised approximately perpendicular to the flow direction. Testing has shown that for circulatory or oscillatory 2D “H” boundaries, a “BOUNDARY VISCOSITY FACTOR ==” of up to 5 will have no measurable or adverse effect on model results, but can significantly improve the flow patterns at the boundary/link. To ascertain the effect, run one or more sensitivity tests applying different factors. As an example, a model of the Bay of Fundy with a large ocean tidal range (16m!) and difficult tidal boundary location performed well with a factor as high as 5 without any detrimental effect on the general flow patterns within the model. For further reference in the 2013-12-AC release notes, please see Item 68(e). Wishing you happy modelling. Regards the TUFLOW team.
  14. Hi All, Please find attached a simple hypothetical pipe network that may help explain some of the output TSL values. TSL.pdf
  15. Hi all, The following post is based on a recent question to TUFLOW support: Question What equations does TUFLOW use to calculate flow and velocities through a 1d sluice gate (SG)? Bernoulli? Answer 1. If the flow is not in contact with the gate, and a weir is specified in the channel type (eg. “SG WB”) the corresponding weir equation is used otherwise a simple 0.5 contraction and 1.0 expansion loss is used with adjustment for the approach/departure velocities as per equations provided in the attached figure, VelocityAdjustment.png (see also Section of 2010 manual). 2. If the flow is in contact with the gate the same equation as per the HEC-RAS manual is used, ie. refer attached figure HECRAS_SluiceGate.png. The default value for C is 0.6, but can be varied by the user. 3. For submerged conditions this depends on the submergence and also follows the HEC-RAS approach extracted from the HECRAS Manual within HECRAS_SubmergedSG.png 4. Note that the velocity reported for a sluice gate is based on the flow area approaching the gate (note, not the flow area under the gate). Therefore, especially for submerged gates, the velocity might appear to be low. We can look into changing this. Note that how the velocity is reported has no bearing on how much flow occurs through the gate. Should you have any further questions, please feel free to contribute. Kind regards, Mitch.