2D connection error

[Evan Murdock]

I’m having an issue with an internal 2D connection, modeling a road crossing within the 2D flow area.

I had previously modeled this without issue in a pure 2D model; it ran as expected. However once I appended a 1D model to the upstream end I’m now getting the following error:

ERROR with Connection(s)

The SA 2D Connection at County J
has an error with the connection.
Check that the “From:” is set correctly.

Error starting unsteady simulation – Stopping compute process

Of course I’ve checked that the “From:” is set correctly; it is both from and to “Flow Area” which is as expected.

I have regenerated the mesh at different densities, saved and restarted RAS, even deleted and recreated the crossing. It works fine when there’s no crossing present, but when I put in the crossing from scratch it fails again in the same way. Googling the exact wording of the error brings up nothing.

Any help would be great!

[Luis Partida]

Hi Evan, a couple things here. The first is your model will be extremely unstable and takes a lot of “tricks” if you do not use a 1D storage area to connect the 1D to 2D domain. And now for your error message; The direction in which you draw the connection matters. It sounds like you just need to delete the SA2D connection and redraw it in the opposite direction and youll be good to go.

[Evan Murdock]

Thanks Luis –

I haven’t had any issues with flow stability; I can run it fine with the crossing removed and the results seem as expected.

I tried deleting recreating the crossing from either direction; I get the same error although if I draw it backwards it says ‘Check that the “To:” is set correctly’.

If I have it set up as a pure 2D model it runs fine, which suggests there’s something about connecting the 1D portion of the model that creates the issue. Which is strange to me.

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