PDA

View Full Version : flood modeling - simulation failed



Flo
December 4, 2013, 07:06 PM
Hello,
I’m starting on ICM and I have problems with my simulation.
I built a network with several reaches and bridges (no error message)
I have inflows for each upstream node (4 profiles) and a tide level for the outfall. This data correspond to an actual rainfall event for which the peak flow is about 5000m³/s.
I selected a 10s timestep.

My simulation failed during initialisation phase. In the log file, I find the following message :
“ Message 261: Too many time step halvings - cannot continue.
Message 250: Initialisation failed for event 1.”
I tried to change simulation parameters, to simplify my network but nothing works.

Can anyone help me solve this problem?
Thanks.

Duncan Kitts
December 9, 2013, 02:07 AM
Hi,

The initialisation phase determines the initial state conditions based on the boundary conditions at the start time of the simulation. Firstly check that you do not have any initial flooding as this is a common reason for the failure of a model to initialise. If flooding is occurring you may want to change the start time so the inflows are not at a peak.

If there is no flooding then it could be due to a control structure fluctuating in and out of different states. e.g an orifice (acting as an orifice or as a weir). You could by tick the 'Timestep log' option in the diagnostics part of the run dialogue. Then rerun the simulation which will provide you with additional timestep information about the convergence. This will provide a hit count of convergence failures for nodes and links during the initialisation, you should investigate the boundary conditions associated with the nodes/links highlighted in the timestep log.

Failing that, please feel free to send the model to support@innovyze.com and we will investigate further.