User Forum of Software BASEMENT

maarnold

Advanced_User

Registered: 2014-09-13

Posts: 28

Inner Gate/ Inner Weir

Hello
I created a very simple case with a trapezoidal channel to test the inner boundary condition gate.
It seems that changing the parameter "level" has no influence on the water surface elevation. It looks like the inner boundary condition is neglected in the calculations.
You can find the case under the following link (dropbox)
Gate Case

Update:
I also checked the inner boundary condition "weir" with constant "width", "level" and "level file", "width file" for different geometry files. All the changes have no influence on the simulation results.

Mat

Last edited by maarnold (2016-07-15 08:50:37)

René Kaufmann

User

Registered: 2016-01-28

Posts: 22

Re: Inner Gate/ Inner Weir

Hi

Since V2.7 there is a problem with the gate. I tried to transfer my 2.6 model to 2.7, but as soon there is a gate in the model, i get an error.

Did I forgot a parameter or is there a bug?

Case 0:
No Gate --> No Problem (I didn't checked the results)

Case 1:
INNER_BOUNDARY {
    type                 = gate
    cross_section_name_1 = QP36
    cross_section_name_2 = QP37
    gate_type            = sluice_gate
}
Result: Water can't flow through the gate

Case 2:
INNER_BOUNDARY {
    type                 = gate
    cross_section_name_1 = QP36
    cross_section_name_2 = QP37
    gate_type            = sluice_gate
    gate_level           = 540.82
}
Result:
ERROR -> InnerGate boundary: undefined operation!

Case 2:
INNER_BOUNDARY {
    type                 = gate
    cross_section_name_1 = QP36
    cross_section_name_2 = QP37
    gate_type            = sluice_gate
    gate_bottom_level    = 540.82
}
Result: Water can't flow through the gate

Case 3:
INNER_BOUNDARY {
    type                 = gate
    cross_section_name_1 = QP36
    cross_section_name_2 = QP37
    gate_type            = sluice_gate
    gate_level           = 545.82
    gate_bottom_level    = 540.82
}
Result: Water can't flow through the gate

Case 4:
INNER_BOUNDARY {
    type                 = gate
    cross_section_name_1 = QP36
    cross_section_name_2 = QP37
    gate_type            = sluice_gate
    gate_level           = 540.82
    gate_bottom_level = 538.75 //Ground level
}
Result: Water can't flow through the gate

Thank you

sajjad

User

Registered: 2014-10-01

Posts: 101

Re: Inner Gate/ Inner Weir

I agree with you. In 1d basechain v 2.6, the simulation results are insensitive to the gate level. I too experienced it. When I transferred the model to v. 2.7 , the simulation stopped citing non-convergence of Newton's method. This seem to confirm rene kaufmann's observation.

Last edited by sajjad (2017-02-20 04:07:03)

Stephan Kammerer

Developer

Registered: 2015-03-31

Posts: 67

Re: Inner Gate/ Inner Weir

Dear users,

let me clarify some issues regarding the Inner boundary in 1D. To me it looks like there is some confusion regarding mandatory tags for the implementation. Be aware that for the latest version 2.7 the inner boundaries have been revised und the tags have changed. This means, it's no possible to use a command file of version 2.6 without adapting the tags for the INNER_BOUNDARY.

@Maarnold: It modified your "Gate Case" example slightly and implemented an Inner Boundary type=gate with the syntax of version 2.7. The files can be found under the following polybox link:

Test case Inner Gate

As fare as I see, the model runs without problems and reacts as expected to geometrical modifications like stated above (width, level, ...) Here and example of the INNER_BOUNDARY block with some additional explainations. The Inner Boundary (in this case empirical gate formula) is used to determine the flux over the edge between CS10 and CS11.

INNER_BOUNDARY {
        type                 = gate               
        cross_section_name_1 = CS10               //CS upstream of the Inner boundary
        cross_section_name_2 = CS11               //CS downstream of the inner boundary
        gate_type            = sluice_gate
        gate_bottom_level   = 1.05                   //bottom of the gate at 1.05m, in same unit as elevation defined in geometry (z_talweg CS10=1.1m, z_talweg CS11=1.0m)
        gate_level           = 1.5                       //level of the gate at 1.5m -> opening of the gate = 0.45m 
        width                = 4                           //width of the gate opening = 4m, gate opening ist rectangular
        contraction_factor   = 0.62                  //default value of contraction ceofficient
    }

We are aware that the Inner Boundary topic is not yet well documented in the GUI help, respectively in the manual. There will soon be some additional documentation including some definition sketches.
So far, I hope this example helps

sajjad

User

Registered: 2014-10-01

Posts: 101

Re: Inner Gate/ Inner Weir

Thank you Stephan. Yes, now it works with v 2.7. The difference this time is the inclusion of the tag 'gate_bottom_level' benefiting from the Stephan reply. Earlier, i was erroneously believing it  as  being equal to the talweg of the x-sections immediately u/s and d/s of the gate.

René Kaufmann

User

Registered: 2016-01-28

Posts: 22

Re: Inner Gate/ Inner Weir

Thank you Stephan for your help.

Your example is running, while I'm using the same concept for inner boundary as you, my model gives the following error message:
ERROR -> InnerGate boundary: undefined operation!

To solve this problem you have to take the appropriate initial condition: instead of the dry use backwater.