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Adaptive timestep

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Anonymous
2010-01-19
2013-04-25

  • Anonymous
    2010-01-19

    Hi,

    I noticed that when using adaptive timestep, the timestep size keeps getting bigger and bigger. It looks like it exceeds the Courant number I nominated. Is this normal or is there something incorrect in my setup?

    Additional information:
    Version: OpenFVM v1.3;
    OS: Windows XP;
    Binary released on Sourceforge (i.e no modification);
    Sequential analysis;\
    Solving for U, V, W and P (not energy equation).

    Thanks in advance
    Julien

     
  • Billy Araujo
    Billy Araujo
    2010-01-19

    Adaptive time step should only be used with free surface calculations. This because it only respects max. Courant at the interface because it is a limitation of the free surface method used.

    Maybe I could modify it to work with all simulations but it tends to make the calculations unstable. I suggest using a fixed time step running some a few calculations first to check if suitable.

     

  • Anonymous
    2010-01-20

    Thanks a lot for the info. I did not know that it was for free surface only. I will go down that the path of the fixed time-steps.

    It may be useful to stop the simulation if adaptive time-step is selected without free-surface.

     
  • Billy Araujo
    Billy Araujo
    2010-01-20

    You are right it should give a warning or something. I will consider this in next revision.