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time-dependent solver
Posted Jun 28, 2012, 2:33 a.m. EDT Chemical Reaction Engineering 1 Reply
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I am simulating the electrolysis. I want to simulate with respect to time. and that time range is very small with very small step size.
I am able to simulate it for time 100 secs i.e. (0 1, 100). In that when I am using time-dependent solver for range ( 0.001, 0.00001, 0.02). I am getting error massage "Failed to find consistent initial value. Last time step is not convergent".
I am able to simulate it for time 100 secs i.e. (0 1, 100). In that when I am using time-dependent solver for range ( 0.001, 0.00001, 0.02). I am getting error massage "Failed to find consistent initial value. Last time step is not convergent".
1 Reply Last Post Jun 28, 2012, 4:12 a.m. EDT
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Posted:
1 decade ago
Hi
that means, from my experience, that your initial values are too far away from the expected results that the solver cannot
find a valid solution. often this comes from the fact that you turn on suddenly a load, a flux or a voltage. Try using a step() function to smooth-en the turn ons, or give a better guess for your initial conditions.
Also in transient analysis you have often ringing or inertial term effects not always tough of (particular in structural or acoustics) then turning off the "inertial terms and use quasi static" solve once, study the results, apply this as initial conditions for another run with inertial terms. Other times you might use a stedy state solver to fix good initial conditions, and then run a time series. It is very depending on your model
--
Good luck
Ivar
that means, from my experience, that your initial values are too far away from the expected results that the solver cannot
find a valid solution. often this comes from the fact that you turn on suddenly a load, a flux or a voltage. Try using a step() function to smooth-en the turn ons, or give a better guess for your initial conditions.
Also in transient analysis you have often ringing or inertial term effects not always tough of (particular in structural or acoustics) then turning off the "inertial terms and use quasi static" solve once, study the results, apply this as initial conditions for another run with inertial terms. Other times you might use a stedy state solver to fix good initial conditions, and then run a time series. It is very depending on your model
--
Good luck
Ivar