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March 22, 2019 at 6:02 pm in reply to: How to disable a junction but keep it in the geometry? #12128cameronParticipant
You shouldn’t just add the peak flows unless they have coincident peaks. Usually the flow downstream of a confluence does not equal the sum of the trib and the main stream flow upstream of trib.
A lot of FEMA studies are done using peak regression flows or hydrographs that have been calibrated to regression flows as there is no other calibration data.
The answer about turning off junctions is, it is not possible. Once a junction is placed, you will need to specify reach names and junction inputs.
cameronParticipantI don’t get the error on my machine. I did change the inflow hydrograph as you had it going for hundreds of hours.
cameronParticipantCan you post your model for me to download?
cameronParticipantDoes this still occur if you delete all of the structures?
What is your downstream condition?
March 12, 2019 at 2:21 am in reply to: surface generation during 2d run is this type, how i solve this problem #12125cameronParticipantwhat is your time step? If it is too large, it will create a floodwave that is not real.
cameronParticipantIt would be in the p01.hdf file or what ever plan you are running. You would have to dig into the outputs until you get to the velocity.
cameronParticipantyou are going to have to post some pictures of the model.
What is your timestep and mapping output interval? Did you have a warm up period?
cameronParticipantVelocity is calculated at the vertices of each mesh. My guess is that it is taking an average from all of the vertices (Vx and Vy). When I have time, I will look into this more.
cameronParticipantYou can turn on detailed output for lateral structures in the plan|options|Set Log File Output Level menu. Just specify the lateral structure and use level 2 output or greater.
Once it is done running, a log file is created in the project folder which shows the iterations and what it is trying to solve. It makes an assumption based on your initial assumption in the Steady Flow Data|Options|Initial Split Flow Optimization window.
It tries your first assumption and then calculates something, it then takes what was calculated and keeps going until it either converges or stops due to max iterations. You can specify a few things in the tolerance window on how many iterations and a Flow Tolerance Factor.
I usually look to see if it is converging or with the default 20 iterations. I then begin to tweak the weir coefficient up or down to see how sensitive it is. You can then play with it until it converges or sometimes you may have to break it up into multiple lateral structures to get it to work correctly.
One thing to note is that the discharge in the split reach is important as it can cause the model to converge or diverge really easy. What I mean by this is if you have the flow spilling into another reach that is supposed to be dry, HEC-RAS doesn’t allow dry reaches so you have to put a dummy flow in there (10cfs or something). The dummy flow can impact the lateral structure so you may have to tweak that as well.
March 11, 2019 at 7:47 am in reply to: RasMapper ability to add Vertices on existing features #12121cameronParticipantYou can do this in Mapper really easy. In HEC-RAS 5.0.6 they added some new features as well. In Mapper in edit mode, just double click on the feature and if you hover over the line, a point will show up. Just click and it adds a point. If you need to add XS, you can do that as well and have it extract the terrain data and calculate reach lengths and bank stations as well.
cameronParticipantWhen calculating the velocity, the max velocity might be right when a grid cell gets wet for the first time and be unrealistic. If you really care about velocity, then you should run a hotstart/restart to resolve that issue.
cameronParticipantChapter 12 of the HEC-RAS Hydraulic Reference Manual. Check out page 12-30
cameronParticipantWhat would be easier would be to use a script to extract the velocity at max depth from the hdf file and then create a raster from that. You could then use either scripts or ArcMap to create the D*(V+0.5) raster.
cameronParticipantYour graph is showing the inflow into the reservoir. This means a negative inflow is flow leaving the storage area due to the breach.
January 14, 2019 at 12:45 am in reply to: Multi Domain 2D Model Using Effective Precipitation #11154cameronParticipantyes. It is the effective precipitation hyetograph.
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