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Shahidul Islam

Model is giving all output value zero

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Hello,

I am doing a SMS-SRH 2D model. When I ran the model, it gave me all output value zero. There are several discontinuity in boundary line after mesh generation. Is that creating the problem?

I have attached a screenshot herewith.

sdas.JPG

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Hi,

It is hard to say what may be causing the issue you are describing. You might investigate why the boundaries are irregular, but I would not expect those to be the cause of all output values being zero. Could you also give us a screenshot of the model in plan view with your BC coverage displayed? One thing you may want to check is that your materials polygons all are set the way you want them, if a materials polygon is left as the default of "Unassigned" or if there are areas of the mesh which do not have materials polygons covering them, then those elements will be inactive for the run.

-Cody

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Sir,

Thank you for your reply.

I have tried many times but failed to identify the problem. There must be some problems which I don't know.

I am giving you the download link of file containing  data and also attaching the required screenshot. Kindly, see the attachment and let me know, what may be the problem.

https://drive.google.com/open?id=15azgnF0TtRosOBNtQHYZKK81aOMw92T9

Thanking you,

Shahidul Islam

Plan view.JPG

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Shahidul,

Which version of SMS are you using? I ran the simulation with SMS 12.3 and it is giving results consistent with the input parameters.

-Cody

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Sir,

I am using 12.1.6 version of SMS. I ran the model again and this time, model gave me better result.

I have some more questions which are given below:

1. Are there any hard and fast rule for creating domain coverage ? As for example, is there any rule that domain should be within TIN?

2. How can I view the number of elements in existing mesh?

3. I want to know about time step and simulation time for running hydraulic model which I have to input into model control section. If you have any effective document defining this terms, provide me, that would be very helpful for me.

Thanking you.

Shahidul Islam

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I am glad you are seeing better results. For best results, when creating your domain coverage you should create it within the areas you have elevation data (TIN or Raster). If there are areas where you slightly go outside of the TIN edge there is an option to "Extrapolate" elevations for areas outside of the elevation data using an IDW interpolation. That is found in the "Scatter Options" when you are assigning a scatter data set for the mesh generator polygons. Please keep in mind, that is an extrapolation of data and that if large portions of the domain coverage are outside of the TIN or areas of interest are outside of the TIN this will not be a good representation of those areas.

You can view the number of elements by selecting "File | Get info" and then clicking on the "Mesh module" tab.

image.png.7160c88e0e94635ac50b26146395b5ef.png

I do not currently have any document to share on the time step. In the future there will be a guidance document available online that will have more information about selecting a time step. Typically most models use a time step between 1 and 5 seconds. There are cases where lower or even higher time steps may be used but you should always review the 2D results as well as any structure output data files (if applicable) to make sure everything is hydraulically stable.

-Cody

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