Discussion Forum

Hi,

in the Study you can define two Time Dependent Steps, so that they will be solved sequentially. In the first Time Dep Step, you use "range(0,1,3600)", in the second Time Dep Step "range(3600,10,21600)".
But remember you have to "link" these two steps: in the second step, you should go to "Values of Dependent Variables", then select "Initial values of variables solved for" and choose "Solution" and "Study 1, Time dependent 1".
I've never used the 3.5 version, so the interface might be different. I hope this helps

Regards

Hi,

I tried but i didn't get the solution.

My question is how I have to put two time steps in solver parameters. range (0,0.1,3600) and (3600,10,21600).

That means, when I put both time range in solver parameters it will first take range (0,0.1,3600) and then

(3600,10,21600) and solved the final problem. So my question is how I have to link them so that it completely
solve the problem.

Thanking you for sharing and reply with me in discussion.

Regards,
Vinay Patel.

Hi,
When I use this technique to sequentially solve two time-dependent steps, I only can access the results for the second one. Is that normal ?

For example, (0,1,10) for step 1 and (10,2,30) for step 2. And then, I only can plot results from 10 to 30 and evaluate integrals on this time range. Is it normal ?

I thought I was doing something wrong. To have an evaluation of an integral from 0 to 30, what should I do ? Should do a first study only with step 1, then compute a study with both step 1 and 2 and then add the integrals ?


PS : after the option "Study 1, Time dependent 1", I have enter a time. What is it ? is it the time at which it evaluates solution as the initial value for step 2 ? I if it is on a sane timescale (from 0 to 30), it shouldn't be a problem, right ?

Thank you very much

Simon

Hi Simon,

I have exactly the same problem as yours. I added two sequential time dependent steps in the same study but the solution only provides data for the second step.

Have you found the solution yet? Can anyone help us?

Thanks,

Shailesh

Hi,

In the latest version for COMSOL Multiphysics (5.3), you can add a Combine Solutions step to the study, in which you can concatenate (join) two time-dependent steps and then use the output from the Combine Solutions step to postprocess the solution for both steps. See

www.comsol.com/blogs/how-to-manage-multiple-solutions-in-comsol-multiphysics/

for more information.

Best regards,
Magnus Ringh, COMSOL

HI Magnus,

Many thanks for replying. I am using 4.4 version, is there any way this can be achieved in this?

Thanks

Shailesh

Hi Shailesh,

I haven't used version 4.4 in a while, but I don't think so. I strongly recommend updating to version 5.3, which includes many new and useful features, one of which is the Combine Solutions study step.

Best regards,
Magnus Ringh, COMSOL

Thanks Magnus