[Alquier]

All right, thank you for your answer The RAS Lad.
I’ve found out the information you talked about in the 2D Modeling Users Manual, chapter 5 in Adding Results Map Layers for Visualization.
This is good to know !

[Alquier]

Hi Blue,

You should check your HTab parameters from Geometric Data Window.
I usually chose to work with an increment of 0.25 and 100 points.

Check also your calculation options like the computation interval, the influence of turning on mixed flow regime and your upstream boundary condition.

[Alquier]

You should go to the Unsteady Flow Analysis Window, Options> View Computation Log File.

That’s very handy to check the mass balance of your model.
If you have issues, it also helps you to know where to start looking for bugs.
However i don’t understand how ras calculates the error.

Does somebody know what is the literal formula used for the error?

[Alquier]

Thank you very much Toby, your advice were usefull.

I have allmost no more balance mass issue in my model.
Splitt cell across lateral structures generated the bug.
You can easily spot these cells by looking carefully your Ras Mapper with the 2D mesh.
I had 8 cells like that along my banks so it was quite a huge bug.
Splitt cells don t bug everytime, and when they do, sometimes I had also to have at least one whole cell between my LSs to avoid the bug.

I’ve noticed that the normal 2D Overflow Computation Method was stabler than the weir equation

[Alquier]

Hi Antonio,

I’ve faced the same issue (see picture below). I changed the Overflow Computation Method from some of Lateral Structures and it fixed my problem. As far as i am concerned it was du to the normal 2D equation. All my LS were in normal 2D equation ans that s what killed the profil plot, even if you don t have any error from the computationals. It may be a bug

[Alquier]

Sometimes it s du to an error in your mesh. Even if you compute your 2D hydraulic tables from Ras mapper the error remain. So in this case you should modify your mesh so as to don’t have any red points in your mesh. It does the trick for me.

[Author]

Posts