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Thread: Initialization failure ICM

  1. #1

    Join Date
    Oct 2013
    Posts
    11

    Initialization failure ICM

    Hi,

    I'm having some trouble initialising a 1D-2D ICM model where I receive the following error in the time-set log:


    Halving: H: SZ95997852.1-, Q: SZ95997852.1-, N: , Reason: Cond Sing
    Message 261: Too many time step halvings - cannot continue.
    Message 317: SIM will now attempt a new initialisation phase with a phase in 10**4 times the value in simulation parameters.

    The initialisation keeps trying to increase the Sim param until it can't go any further (presumably).
    I have tried increasing 'Max number of timestep halvings - initialisation' in the Sim params to 30 but I still get this error.

    I am also not sure what 'Cond Sing' refers to, and I can't see anything wrong with the long-section near SZ95997852.1.

    Anyone's thoughts would be much appreciated!

    Cheers

  2. #2
    Senior Member

    Innovyze Employee



    Join Date
    Feb 2013
    Posts
    146
    Hi Will,
    Often when you have this issue increasing the number of iterations does not help but lowering the time step and/or using the 2D option "Link 1D and 2D calculations at minor timestep" will help.
    I hope this helps.
    Regards,
    Bob Dickinson
    Innovyze

  3. #3

    Join Date
    Oct 2013
    Posts
    11
    Hi Bob,

    Thanks for the reply.
    I have reduce the timestep down to 10, 5 and 1, with 1D-2D minor time step linking, and I am still getting this same error. Are there any other fixes I could try or aspects of the model I should look into the find the problem?

    Cheers,
    Will

  4. #4
    Forum Moderator

    Innovyze Employee



    Join Date
    Feb 2013
    Posts
    133
    Hi Will,

    Poor initialisation usually occurs for 3 reasons:-
    *Initial Flooding at time zero.
    *A large amount of storage which requires filling. This is usually related to large rivers with tidal boundaries.
    *Model instability and poor convergence.

    Rather than forcing the model through the initialisation phase by changing the simulation parameters it is always worth inspecting the geometry and boundary data to ensure it is appropriate. Feel free to send your model to the support@innovyze.com email address and we'll take a look.

  5. #5

    Join Date
    Oct 2013
    Posts
    11
    Hi Duncan,

    I have had a look at the conduit geometry but can't find anything out of the ordinary. I'll send over a transportable - I will probably have to use Thru Drop Box due to the size of the model.

    Much appreciated.
    Thanks,
    Will

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