TUFLOW 2D Hydraulic Structures: Difference between revisions

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Revision as of 13:39, 2 March 2026 view source Emilie Nielsen (talk \| contribs) Administrators 6,330 edits →What FLC values should be used for 2d_bg bridge if hB/T is below 2 or above 6? ← Older edit		Latest revision as of 14:07, 6 March 2026 view source Anne.Kolega (talk \| contribs) Bureaucrats, Administrators 82 edits m →Pier Losses
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Line 1: = 2D Structure Modelling Theory = The theory behind the modelling of energy losses and affluxes of hydraulic structures is presented in the following webinars by Bill Syme and Greg Collecutt (some of the TUFLOW Developers). ~~These webinars by Bill Syme and Greg Collecutt (the TUFLOW Developers) discus the theory behind the energy losses and affluxes modelling associated with hydraulic structures.~~ *<u>[https://www.tuflow.com/library/webinars/#structures Webinar Link: Modelling Energy Losses at Structures]</u><br> Line 16: Piers are usually smaller than the 2D cell size in real-world flood models. Although flexible mesh solver or quadtree refinement can be applied to reduce the local cell size around the pier, it also comes with an expensive computational cost that could significantly increase the simulation time. More practically, the backwater effect of piers can be modelled as sub-grid form losses. Pier form loss coefficients can be derived from information in publications such as <u>[https://www.fhwa.dot.gov/engineering/hydraulics/library_arc.cfm?pub_number=1&id=5 ''Hydraulics of Bridge Waterways'' (Bradly, 1978)] or [https://austroads.com.au/publications/bridges/agbt08 ''Guide to Bridge Technology Part 8: Hydraulic Design of Waterway Structures'' (AUSTROADS, ~~2019~~2018)]</u>. Energy loss estimated from bridge piers or other obstructions, vertical or horizontal, that do not cause upstream controlled flow regimes like pressure flow, are dependent on the ratio of the obstruction's area perpendicular to the flow direction to the gross flow area of the bridge opening, the shape of the piers or obstruction, and the angularity of the piers/obstruction to the flow direction. For example, using Hydraulics of Bridge Waterways (Bradly, 1978) the approach is: <ol> <li>Calculate the ratio of the water area occupied by piers to the gross water area of the constriction (both based on the normal water surface) and the angularity of the piers. These inputs are used to calculate "J" in the FHA documentation.</li>