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cameronParticipant
If you have the coordinates available in xy data then you just set it in the geometric data editor for each one. You could also import in the line work using GeoRAS.
cameronParticipantDid you try this in Unsteady?
cameronParticipantYou could get this from the hdf file. It lists the depth at each output interval so you could develop it in excel or other method by having it calculate the time of the max depth.
cameronParticipantFlowpaths are generated in GeoRAS and should be three of them: channel, left overbank, and right overbank. Sometimes it helps to draw before cross-sections as you want the cross-sections to be perpendicular to the flow..
August 27, 2017 at 3:19 am in reply to: Problem connecting reach with 2D flow area (lateral structure) #10851cameronParticipantMake the lateral structure station 3101 or 3099 depending on where the starting point of the lateral structure is.
cameronParticipantThere is a thread that discusses a similar issue. Basically it came down to the placement of the lateral structure along the mesh elements.
cameronParticipantA few additional thoughts:
I would switch to a 2D model if you have the option, far more stable.
You need to update the HTAB data for the cross-sections to be every .25 feet or less.
Bump up the roughness to 0.1 or higher just downstream of the dam as 0.032 is low for all of the debris that would be coming down.
I would add ineffective areas so that the active top widths don’t change much if at all downstream of the dam.
You may need to interpolate xs.
You set initial conditions to 0 cfs in the main channel, the model does not like this as you can’t have zero flow in a cross-section or HEC-RAS will blow up.
You timestep of 2 minutes is probably too high and should be lower around 15 to 30 seconds maybe less.
cameronParticipantAre the downstream cross-sections from the dam a canyon or wide open? Did you attempt to increase roughness values to 0.1 or so to help stabilize the model? Did you try to add interpolated cross-sections?
cameronParticipantHard to say what the error is as that is generic. Does it crash right away or after running for a little bit.
cameronParticipantDid they say if the sediment manual was a separate document or as part of another document? Chapter 13 of the reference manual has information on Sediment transport which appears to be updated from 4.1. I could not find the document I had from a few years ago, but it did have discussion on both the new unsteady sediment capabilities and BSTEM (toe erosion) and maybe that is what they will be uploading soon.
I will take a in depth look when I get some time, but that may not be until September.
cameronParticipantIt would have more to do with the channel data than the streamline. You can turn on the XS interpolation layer in Mapper to see what it is doing.
You could interpolate a few cross-sections to make the spacing closer for when you do the interpolation.
cameronParticipantThe smaller the grid cell the smaller the time step. With that small of a grid cell, your time step will need to be 1 second or less most likely.
cameronParticipantYou use GeoRAS which can be downloaded from HEC’s website, use a plugin from QGIS, or use SMS or WMS.
cameronParticipantYou need to have terrain that covers the cross-sections so it can create floodplain maps. It looks like your terrain does not cover the cross-sections.
cameronParticipantDid delete the boundary condition for lateral structure in the unsteady flow data editor?
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