Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

just start with a known solution for first time step

Please login with a confirmed email address before reporting spam

Hi,
there is a simple solution, or?
I perform a time-dependent study. But the input variable for the time is not long enough, so I want to repeat this pattern several times. Unfortunately it does not work as I imagine it. How to start with the known solution from the previous study only for the first step of the new study?
Thanks
Markus

3 Replies Last Post 26.01.2013, 10:07 GMT-5
Josh Thomas Certified Consultant

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 25.01.2013, 15:15 GMT-5
Markus,

1st create a new study. In the new study...
Under Step 1: Time Dependent, in the Settings window, expand Values of Dependent Variables.
Check Initial values of variables solved for
Method: Change Method to Solution
Study: Select the Study that you would like to reference
Selection: Select the Time step from that study that you would like to use. In your case, use "Last."

Regards,
Josh Thomas
AltaSim Technologies
Markus, 1st create a new study. In the new study... Under Step 1: Time Dependent, in the Settings window, expand Values of Dependent Variables. Check Initial values of variables solved for Method: Change Method to Solution Study: Select the Study that you would like to reference Selection: Select the Time step from that study that you would like to use. In your case, use "Last." Regards, Josh Thomas AltaSim Technologies

Josh Thomas Certified Consultant

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 25.01.2013, 15:15 GMT-5
Markus,

1st create a new study. In the new study...
Under Step 1: Time Dependent, in the Settings window, expand Values of Dependent Variables.
Check Initial values of variables solved for
Method: Change Method to Solution
Study: Select the Study that you would like to reference
Selection: Select the Time step from that study that you would like to use. In your case, use "Last."

Regards,
Josh Thomas
AltaSim Technologies
Markus, 1st create a new study. In the new study... Under Step 1: Time Dependent, in the Settings window, expand Values of Dependent Variables. Check Initial values of variables solved for Method: Change Method to Solution Study: Select the Study that you would like to reference Selection: Select the Time step from that study that you would like to use. In your case, use "Last." Regards, Josh Thomas AltaSim Technologies

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 26.01.2013, 10:07 GMT-5
Thanks Josh,
I know this possibility.
But I was not sure if your solution does not at any time following step refers in the approach first to this initial solution. In my model, it initially looked like this. Even if I not pick the "last" time step, but "automatic", it works exactly the same. So I was really confused.
Another solution was than more familiar to me:
You export the final solution (eg in case of 2D as xy-matrix) and imports it as int1(x, y) and use it as initial variable and repeat the same study. It works like your proposal, Josh.
Best Regards,
Markus



Markus,

1st create a new study. In the new study...
Under Step 1: Time Dependent, in the Settings window, expand Values of Dependent Variables.
Check Initial values of variables solved for
Method: Change Method to Solution
Study: Select the Study that you would like to reference
Selection: Select the Time step from that study that you would like to use. In your case, use "Last."

Regards,
Josh Thomas
AltaSim Technologies

Thanks Josh, I know this possibility. But I was not sure if your solution does not at any time following step refers in the approach first to this initial solution. In my model, it initially looked like this. Even if I not pick the "last" time step, but "automatic", it works exactly the same. So I was really confused. Another solution was than more familiar to me: You export the final solution (eg in case of 2D as xy-matrix) and imports it as int1(x, y) and use it as initial variable and repeat the same study. It works like your proposal, Josh. Best Regards, Markus [QUOTE] Markus, 1st create a new study. In the new study... Under Step 1: Time Dependent, in the Settings window, expand Values of Dependent Variables. Check Initial values of variables solved for Method: Change Method to Solution Study: Select the Study that you would like to reference Selection: Select the Time step from that study that you would like to use. In your case, use "Last." Regards, Josh Thomas AltaSim Technologies [/QUOTE]

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.