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remslie14-Alexandrite
14-Alexandrite
October 22, 2013
Question

Function will not converge

  • October 22, 2013
  • 1 reply
  • 24520 views

Hi,

I am calculating dynamic pressures on a moving gate and cannot get the integral for vertical force Fv(t) to converge. I have tried adjusting the convergence tolerance but this does not seem to make any difference. Any clues would be appreciated.

Cheers

Ross

    1 reply

    A
    AlanStevens19-Tanzanite
    19-Tanzanite
    October 22, 2013

    See if the attached helps.

    Alan

    R
    remslie14-AlexandriteAuthor
    14-Alexandrite
    October 23, 2013

    Alan,

    Yes indeed your modification did help. If I now take this function and wish to use it in an Odesolve block as the final step I hit the wall with another error. Any clues to de-bug this would be appreciated.

    The problem I am trying to solve can be unstable with divergent response, however, it should be stable and converge when the damping (zeta) is a modest value (i have used 0.05 or 5%).

    Thanks again

    ross

    A
    AlanStevens19-Tanzanite
    19-Tanzanite
    October 23, 2013

    Ross

    The attached works - the ODE solver worked ok, it was just the plotting that confused it (because of a previously defined set of t's).

    However, I notice that the solve block contains M(t), which is a function of Fv(t), which is in turn a function of pp(t,y), which is a function of dtheta/dt - in your case a previously set function of dtheta/dt, not the one you are currently solving for within the solve block. Is this what you intend?

    Alan

    Edit. Also, it is a function of theta, through F(t,s). Again this isn't the theta that the ODE block is solving for. Is this right?

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