1D Bridges: Difference between revisions
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=Introduction=
The following section looks at bridges using the 1D component of TUFLOW, for information on bridges in the 2D domain please see the following section on [[TUFLOW_2D_Hydraulic_Structures | 2D hydraulic Structures]] and [[Tutorial_Module06#Bridge_Modelling_Option_3:_2D_Layered_Flow_Constriction | Module 6]]. <br><br>
1D Bridge channels do not require length, Manning's n, divergence or bed slope (so they are effectively zero-length channels) and rely on a reasonable estimate of energy losses associated with re-expansion of water after the vena-contracta (often referred to as entrance losses), expansion of water downstream (exit losses), pier losses, bridge deck and guard rail losses. Other factors include accounting for occurrence of bridge deck pressure flow and the effects of bridge skew and multiple bridges (shielding effects of an upstream bridge on a downstream bridge). <br><br>
Care must be taken when choosing the approach to modelling the bridge and setting appropriate loss values.
As a typical rule-of-thumb, if the channel upstream &/or downstream of the bridge is modelled in 1D then the bridge should also be modelled in 1D. Ideally any change in the channel from ESTRY 1D to 2D or vice-versa should also occur at a structure (i.e. bridge, culvert, etc) to facilitate the transition in solution schemes. The images below displays a typical preferred setup, however as is the case with hydraulic modeling your particular model situation may be different and therefore not always conform to these ideals.<br>
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