Welcome to the RAS Solution Forums HEC-RAS Help What is the meaning of cenvergence, error, wsel … in simulation message?

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  • #6304
    Anonymous
    Guest

    hello everyone.
    I ran 2D simulation (full momentum) and i had some messages during my simulation (see picture – link below). I want to ask what exactly mean WSEL , ERROR and CONVERGENCE for particular cell? When these messeges appear? What is the meaning of those values? Are those informations usefull for simulation setup?
    Thanks for your response.

    Maximum iterations of 20 Cell WSEL ERROR CONVERGENCE
    01SEP2008 01:42:44 2dArea Cell # 4082 240.97 0.0031 2

    https://drive.google.com/open?id=0BzWkBKnv4-QcRVZyM1h6VGpCOFE

    #10305
    cameron
    Participant

    Page 4-9 of the 2D manual discusses.

    Bascially 1 and 4 values are converging and 2 and 3 are diverging solutions.

    #10306
    Anonymous
    Guest

    Thank you. OK so my model is diverging in 1:45:44 in cell #4082, but what exactly does it mean value of WSEL and ERROR? what is happing in my cell at WSEL = 240.97?

    Maximum iterations of 20 Cell WSEL ERROR CONVERGENCE
    01SEP2008 01:42:44 2dArea Cell # 4082 240.97 0.0031 2

    And one more question – what is the best aprroach to converging solution?
    increase iteration? or increase theta (to 1) ? create restart file and use it as initial condition ?

    #10307
    cameron
    Participant

    first off, the error you have for that cell is small and I would not worry about it. depending on what the study is for, it may be ok to have values up to 1. Lowering the timestep is one of the easiest ways to help with convergence otherwise you would need to adjust iterations or adjust grid cells. A restart file/initial conditions may be helpful depending on when the error occurs in the simulation (at the beginning or when flow first enters a cell).

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