User Forum of Software BASEMENT

ingridsenn

User

Registered: 2016-11-28

Posts: 10

boundary for sediment inflow

Hello all,

how can I model a sediment inflow (boundary with type sediment_discharge) in an other boundary than upstream (or downstream)? I want to add the sediments 3-4 cross section below my hydraulic upstream boundary, hoping to reduce the boundary effects which so far seem to prohibit correct sediment transport simulation. Is there a possibility in basement 1D to do so?

Thanks,
ingrid

Lukas Vonwiller

Developer

Registered: 2014-09-04

Posts: 130

Re: boundary for sediment inflow

Hi Ingrid,

You can add an external sources on cross sections:

MORPHOLOGY
{
   [...]
   SOURCE
   {
      EXTERNAL_SOURCE
      {
         [...]
      }
      EXTERNAL_SOURCE
      {
         [...]
      }
   }
   [...]
}

Hope this helps!
Cheers, Lukas

ingridsenn

User

Registered: 2016-11-28

Posts: 10

Re: boundary for sediment inflow

Hi Lukas,

Thanks for your reply. I tried this, but my bedload does not appear anywhere at all in the output file... I guess it did not get picked up, but I dont have any deposition either... so something in my file must be still wrong! How do I need to prepare my external_source file? And why do you add two external sources in the above example - can I also just add one if I want to add all my bedload in one cross section, or do I need to add one for a water source (which I actually dont have) and one for sediment?

Thanks
Ingrid

Lukas Vonwiller

Developer

Registered: 2014-09-04

Posts: 130

Re: boundary for sediment inflow

Hi Ingrid,
In the Help botton of the GUI it tells you: The file needs two columns, time and corresponding sediment inflow [m3/s].
You can add as well an external source in the HYDRAULIC block at the same cross section.

Hope this helps!
Best, Lukas

ingridsenn

User

Registered: 2016-11-28

Posts: 10

Re: boundary for sediment inflow

Hi Lukas,
I have already noticed that note on the GUI, so my file must be correct. Concerning the hydraulic source, I do not want to add a hydraulic source actually, I just wanted to make sure I do not need to. So if I understood you right, I can indeed just put an external sediment source only. But I am confused, having everything set as you described (it seems), I still get just no sediment transport at all in the model, nor any deposition - as if nothing was coming into the model through the external source. Is there somewhere else that I must activate the external source? Can you please check my inputs, I paste my whole morphology block below. Cross section 2819.60 is a the third or fourth cross section after the upstream boundary. (and sorry for the maybe messy order of some of the elements... I continuously extendend my morphology block...)
Best & thanks, Ingrid

MORPHOLOGY {
            PARAMETER {
                porosity = 30
                density  = 2000
            }
            BEDMATERIAL {
                GRAIN_CLASS {
                    diameters = (8 33 73 143 595 1000)
                }
                MIXTURE {
                    name            = mix1
                    volume_fraction = (20 20 20 20 20 0)
                }
                SOIL_DEF {
                    name = soil1
                    LAYER {
                        mixture          = soil1
                        bottom_elevation = -10
                    }
                }
                SOIL_ASSIGNMENT {
                    index = (1 2)
                    soil  = (soil1 soil1 )
                    type  = index_table
                }
                MIXTURE {
                    name            = soil1
                    volume_fraction = (0 0 0 0 0 100)
                }
            }
            INITIAL {
                type = initial_mesh
            }
            BEDLOAD {
                PARAMETER {
                    upwind = 0.8
                }
                FORMULA {
                    bedload_formula = smartjaeggi_multi
                }
                BOUNDARY {
                    type   = IOUp
                    string = upstream
                }
                BOUNDARY {
                    string = downstream
                    type   = IODown
                }
            }
            SOURCE {
                EXTERNAL_SOURCE {
                    type          = sediment_discharge
                    file          = geschiebe2000.txt
                    mixture       = mix1
                    cross_section = 2819.60
                }
            }
        }