TUFLOW 1D Channels and Hydraulic Structures: Difference between revisions

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== What entry/exit loss and contraction coefficients should I use for 1D culverts? ==
We don’t provide hard recommendations on the exit and entry losses to use for culverts as we have found different organisations around the world, typically government, have their own guidelines for different types of inlets configurations and require these to be used, for example, the <u>[https://www.ipwea-qnt.com/products-resourcesWeb/qudmWeb/Resources/ Queensland-Urban-Drainag-Manual-QUDM.aspx QLD Urban Drainage Manual]</u> (QUDM). However, it is very important to understand how losses are applied and that different 1D solvers may treat them differently. For cross-checking your results from any hydraulic modelling software, a simple calculation applying the entry and exit losses (allowing for any automatic adjustments as discussed below) to the computed head (V2/2g), plus allowing any surface roughness losses (Manning's equation) for longer culverts, is the best practice for culverts flowing in a sub-critical flow condition (i.e. downstream controlled flow).<br>
 
For the entrance loss values, the approach should be to use values as quoted in the literature or guidelines for the inlet shape and design unless there is evidence to use another value (e.g. comparison with reliable calibration data would indicate different energy losses).
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A trash screen is a physical barrier, typically made from bars or mesh, placed at the inlet or outlet of a culvert, pipe, or channel to prevent debris from entering or exiting the structure.
 
Trash screens can be represented by applying additional head losses and blockage effects in accordance with <u>[https://www.ipwea-qnt.com/products-resourcesWeb/qudmWeb/Resources/Queensland-Urban-Drainag-Manual-QUDM.aspx QUDM]</u> guidance. The approach depends on the location of the screen and the degree of blockage.
 
Possible use cases include: