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You can now Section through the Design (and Existing if you wish) and the Services Model and then draw up the two sets of sections, see below. They have been displayed using the Existing Services Style Set. The example below is a simple example, where all the services are in the same model, but have different string names for different service types. You can also use it for annotating Drainage runs on cross sections too. Its not the easiest thing to do, but with some thought on string and model naming and masking, and an input file, some decent results can be obtained.
Hec ras blog pdf#
In most cases abrupt changes can be fixed by adding extra horizontal n-value break points.Ĭlick hereto download a PDF to follow along with screenshots. For more information, contact Hector Olmos.Every so often, we get asked about annotating Cross Sections with Services. Keep in mind that you need to have smooth conveyance curves.
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Also make sure that the initial flow matches your minimum flow. Adding an initial flow and keeping it as small as possible may provide the necessary stability.
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Try adding extra cross-sections in locations where errors are higher than 1.0 or where the model cannot converge on several time steps.The most accurate answer will come from using a stability factor of 1.0. The stability increases as you approach 3.0, but keep in mind that this also makes your accuracy decrease. In order to improve model stability, try increasing your stability factor from 1.0. Lateral and inline structure stability factors can improve model stability.If a drop structure is present in the model, the best way to represent it is as an inline structure.Lowering the computation interval of your plan file may reduce your error and make the model more stable. Model stability can be sensitive to the computation interval.The model sometimes crashes suddenly and displays a red bar across the computation window stating that the model is “unstable.” Below are some tips to avoid the dreaded “red bar” and for developing a stable running unsteady HEC-RAS model. Unsteady HEC-RAS can be a useful tool for modeling complex river systems however, it can also be more difficult to troubleshoot than steady state models.