2D Area Connection & BC

[Anonymous]

I have a model I am running tests on and was wondering if anyone had any suggestions for the situation I am in.

I have a Fully 2D stream for which there is a flow change location midway along the reach. So i can easily create two storage areas one for the US area and one for the DS area. However, a boundary condition and a DS connection canNOT share the same cell face.

I tried the workaround of putting the BC to the “left bank” cells but the results definitely do not represent an accurate depiction of what is occurring.

[Anonymous]

I am curious if you solved your problem with adding flow midreach. I am also wondering what your approach was for connecting the 2D areas.

thanks.

[Lonnie A]

One way is to place a 1D storage area between the 2 2d flow areas. You can then link the 3 together with a SA connector and put you inflow hydrograph in the 1D storage area.

[Anonymous]

Hi,

I have the same problem, a Fully 2D stream for which there is a flow change location midway along the reach. I tried to place a storage area between the 2 2d flow areas, but in the connection I need to put a weir that should be higher than the river elevation.
I got results that definitely do not represent what is occurring.
Is there another way to put an hydrograph inside a 2d area? (maybe an internal condition).

Thanks

[Kinia]

You don’t have to put a weir higher than your river elevation. You just have to have weir higher than cells of your mesh. In situation when you want to have connection without any embankment or weir just do the connection, copy terrain profile and insert it in weir/embankment. In theory you’ll have a weir but practically you won’t – it’s elevation overlaps your terrain so you won’t have damming.

Hope I helped.

[Anonymous]

Thanks for your answer!

Actually I tried to copy the terrain profile and insert it in weir/embankment, but when I run the simulation this error appears:

ERROR with Connection

The SA 2D Connection at 2
has a weir elevation lower than the cells they are connected to
for 2D Area 2
This is not allowed in HEC-RAS:

So I tried to put a weir higher than the terrain elevation and it worked. It worked but it doesn’t represent the situation that I have. Maybe I’m not doing it right. I didn’t understand when you said: “You just have to have weir higher than cells of your mesh.” Maybe this is the answer for this problem, but I don’t know how to do this.

In the simulation that I’m running I need to insert a Hydrograph in the middle of my 2D cells. If you know another way to do this that isn’t connecting two 2d areas with a torage area, please, let me know.

Thanks a lot!

[Author]

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