Stagnation Points Past Culvert Centerline

[RobertCa]

Hello

Has anyone seen this error before: STAGNATION POINTS PAST CULVERT CENTERLINE PROGRAM ABORTED IN I_CLVRT

It occurs when I try to run a steady flow analysis on a multiple opening project. The models used to run fine but the computations stall out now.

I am using version 5.0.4.

Thank you for your time,

Robert

[cameron]

For multiple openings, you specify starting and ending values for each opening. If two openings overlap, you the program tries to determine where the stagnation point is located. You need to adjust starting and ending points to fix the issue.

[RobertCa]

That’s what I thought was the issue as well.

However these plans ran smoothly before when I made them in 2016. Now when I open them and, without changing any settings, try to run a steady flow analysis, they stall out with that error.

I think I am just thinking about something wrongly because it still doesnt make sense.

This is what my culverts and stag limits look like.

[RobertCa]

I adjusted the cross sections so that the skew angle of the culverts isn’t as extreme. Its not ideal because its not a realistic representation of the site but it ran after that.
That also doesn’t explain how the models ran just fine, even with the skew, in the past.

[cameron]

Why don’t you just place them close to the final stagnation solution from the run that worked? The model is trying to converge to something and it can’t do it which probably has to do with different versions of HEC-RAS, changes made to the geometry, or changes made to discharge.

There have some big changes from 4.1 and 5.0.0 and smaller changes from then on. Bridges and culverts and how they calculate are one of the big changes.

[RobertCa]

The run that worked was just to try to see if the error could be cleared. With every plan in the project failing (including, briefly, a plan that didn’t have a multiple opening at all), I was worried the problem was deeper than just the one error.
Going forward, I’ll set the stag limits close to the edges of the culverts and move if computation errors occur to provide as much room for convergence, like you said.
As an aside, in this particular model, it will fail if opening #1 has any stag limits (upstream xs or downstream xs) projecting into any point of opening #2. It will run to completion, however, if the reverse occurs but with the error “Subroutine SNET_HDF_Q_DISTR” appearing.
Do you know what this new error means?

[Author]

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