User Forum of Software BASEMENT

dazzle

User

Registered: 2015-05-07

Posts: 9

Error Inflow Hydrograph

Hello,

I'm trying to simulate a mountain creek flood scenario with a defined inflow hydrograph I have set up using a separate text file.
However, I'm constantly getting an error that the inflow velocity exceeds 200m/s. This leads to the simulation crashing.

I don't know how to solve this error, since I cannot find an option increase the inflow velocity limit from 200 to say 1,000m/s.
I note that I have set the input hydrograph to an edge boundary, since this is the only option to use such a hydrograph in BASEMENT as far as I have understood the documentation.

I tried to use a controller and a manipulated variable, but this showed no effect.

Would be great if someone knew a solution.

Thanks

Here is the error message:

*******************************************************************************
*!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Warning !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!*
*******************************************************************************
-> A problem occured with the inflow hydrograph boundary. The inflow
   velocity exceeded '200' m/s. All Fluxes are set to 0.0!

Here are the parts of my input file that (may) correspond to the issue:

DOMAIN {[...]
BASEPLANE_2D {[...]
HYDRAULICS {[...]
BOUNDARY {
                type           = hydrograph
                string_name    = Inflow
                file           = Inflow_hydrograph_n1000_20150513.txt
                slope          = 4
                weighting_type = area
            }
}
MORPHOLOGY{[...]
BEDLOAD {
                PARAMETER {
                    bedload_transport        = mpm_multi
                    bedload_factor           = 1.0
                    limit_bedload_wetted     = off
                    lateral_transport        = on
                    lateral_transport_factor = 2.05
                }
                BOUNDARY {
                    type        = IOUp
                    string_name = Inflow_sed
                }
}
}

Sam

Developer

From: VAW - ETH Zurich

Registered: 2014-09-04

Posts: 46

Website

Re: Error Inflow Hydrograph

Hi,
the warning message you received from BASEMENT is actually a WARNING that should help the user to improve the model.
To ignore all the warnings (BASEMENT GUI will then run properly) you can set the log level to zero.
Since a flow velocity of 200 m/s is quite unrealistic you should check your boundary condition setup though: slope, inflow time series, mesh at the boundary, etc.
hope that helps...cheers

Lukas Vonwiller

Developer

Registered: 2014-09-04

Posts: 127

Re: Error Inflow Hydrograph

Hi dazzle

This warning indicates that you have a serious problem at your inflow boundary, don't ignore this warning!
It looks like you have supercritical flow at your boundary, maybe due to very low flow depths, high bed slope, or dry initial condition.

As Sam mentioned already above, to get to run your model properly, you have to check your slope and mesh at the boundary, and
if necessary change the location of your model boundary (avoid supercritical flow at boundary).

Hope that helps!
cheers

dazzle

User

Registered: 2015-05-07

Posts: 9

Re: Error Inflow Hydrograph

Hi Sam, Lukas,

thank you for your help. The problem was indeed the input mesh, especially at the boundaries, as I had way too many small triangles.
After editing the mesh and generating smaller triangles, the simulation now runs smoothly and without generating any errors

Best
dazzle