User Forum of Software BASEMENT

basemind

User

Registered: 2015-10-28

Posts: 15

Negative discharge over weir

Dear fellow modelers,

another day, another problem! I wanted to implement a weir in my perfectly running model and got the following error message:

I already tried the following approaches (all to no avail, though):

1. Change the upstream direction of the inflow and outflow boundaries (it was correct before)

2. Leave a little gap before and after the weir so that my initial waterdepth of 1m isn't applied there

3. Leave just a little gap downstream and no gap upstream

4. Like 3. but with an even higher initial depth upstream (2m instead of 1m)

5. Like 4. but with an applied velocity in downstream direction (directly facing the weir)

6. Leave just a little gap upstream and no gap downstream

As soon as any water touches the weir (from downstream or upstream), I get the above error pop-up.

This is what my weir looks like (here with approach #4):

These are the material types and nodal elevations around my weir; the weir is set to a fixed height of 490,3m:

Last edited by basemind (2015-12-09 13:01:59)

JoJo92

User

Registered: 2017-01-31

Posts: 2

Re: Negative discharge over weir

Hi, i'm presenting the same problem and i wanted to ask if you were able to resolve that. Kind regards!!

Hering

User

Registered: 2015-11-25

Posts: 5

Re: Negative discharge over weir

Alaz I have no solution.
I am waiting for improvement of the software.
Werner Heller

Alyssa

User

From: Aix-en-Provence, France

Registered: 2019-10-28

Posts: 41

Re: Negative discharge over weir

Hi

This is quite an old topic, but I am stuck with the same issue and there doesn't seem a solution proposed here. I have the issue on an inner boundary weir in 2D model. Anyone who knows what this error means? In my case I only have it when my discharge becomes very high. Is there a problem with the water flowing on the side of the weir? It could be the mesh is not good enough around the weir, since it is based on measured cross sections. I already tried to add some elevation points manually (on the banks parallel to the weir), and I managed to model up to a higher discharge, but not yet to the maximum discharge I need. But I am not sure if this is the way to fix it.
Any advice is welcome.

Thanks