TUFLOW 2D Hydraulic Structures: Difference between revisions
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TUFLOW is a 2D solution (not 3D), in the 2d_lfcsh layer the percent blockage and form loss coefficient applied to the cell faces is depth averaged across the entire cell face (across Layer 1, 2 and 3):<br>
*For bridges, where Layer 2 has a 100% blockage applied, the minimum flow width factor of 0.
*Layered flow constriction works by adjusting the flow area of the cell faces by any blockages to generate the correct depth averaged velocity at each face at which the form losses are applied as a fraction of the V<sup>2</sup>/2g kinetic energy. Calculating the correct velocity is critical for determining the losses as the losses are proportional to the velocity squared. <br>
*For a layered flow constriction cell face the flow area cannot be zero above the invert of Layer 1 to avoid a divide by zero in the computations, therefore after applying blockages, a minimum
*If this is unacceptable, and a 2d_lfcsh is intended to be 100% blocked, or even just Layer 1 100% blocked in the case of a fence with a solid base, then the preferred approach is to raise the ground elevation by setting the 2d_lfcsh invert attribute higher or using a 2d_zsh Z Shape modification (e.g. a breakline). <br>
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[[File:100% Blockage Diagram.png | 500px]]
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