Revision as of 04:33, 16 March 2022 view source Chris Huxley (talk \| contribs) Bureaucrats, Administrators 7,789 edits →What form loss coefficient (FLC) values should I use for 2d_lfcsh bridge? ← Older edit		Revision as of 04:59, 16 March 2022 view source Chris Huxley (talk \| contribs) Bureaucrats, Administrators 7,789 edits →What form loss coefficient (FLC) values should I use for 2d_lfcsh bridge? Newer edit →
Line 55: * Layer 2 - Bridge deck: Due to the complexity of flow around a bridge deck (different deck designs/profiles; occurrence of pressure flow), there are no hard and fast guidelines on how to set the FLC for the bridge deck. The best approach is to conduct calibration tests if data are available, otherwise draw upon available information on form loss coefficients corresponding to the drag on similar shaped objects. It is always recommended to at least conduct sensitivity tests with different FLC values to ascertain the importance of the FLC values on the results and whether they have a meaningful impact on the modelling investigation. FLC values for bridge decks for the CUMULATE, METHOD C and METHOD D approaches would typically be in the range from 0.1 to 0.5 for submerged bridge decks~~, without available calibration data to verify model results a value of 0.4 is commonly used~~. For the PORTION approach much greater values are appropriate and are dependent on the deck depth to total depth ratio due to the depth proportioning approach used by PORTION. Should pressure flow occur (where the flow for a time becomes upstream controlled as orifice flow somewhat equivalent to flow under a sluice gate), using a vertical coefficient of contraction of 0.8 a form loss value of 1.56 can be derived as recommended in Hydraulics of Bridge Waterways (1978) (see <u>[https://forum.tuflow.com/index.php?/topic/1419-1d-loss-coefficients-for-bridge-deck-surcharging TUFLOW Forum post]</u>), however, it is not recommended this value is used without calibration or other benchmarking data, and its use should be confined to the PORTION approach only. * Layer 3 - Guard rails: ** The advice for Layer 3 to represent guard rails is similar to Layer 2.

TUFLOW 2D Hydraulic Structures: Difference between revisions