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 The information provided may be out of date.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.

Help!!!! How to define such indicator temperature, Tp

Please login with a confirmed email address before reporting spam

Dear all,

I'm now using Comsol to simulating 3D heat transfer problem. I want to define an indicator temperature Tp in the domain that records every point's maximum temperature the point has ever reached.

Take one point as an example, the picture is attached, in which T is temperature, t1 to t4 are time. I assumes T changes in this way, but actually T is determined by the heat transfer equations.

Initial Tp=T

From time 0 to time t1, Tp=T as T increases in the range [0,t1]

From t1 to t2, T first decreases then increases, but since Tp>=T, Tp does not change in the range [t1, t2]

From t2 to t3, Tp increases with T, as T increases in the range [t2, t3].

From T3 to T4, T decreases to 0, but since Tp>T in the range [t3, t4], Tp does not change its value (which is the temperature at T(t3)

So at any time t, Tp is the maximum temperature of the point from 0 to the present time t

Can someone give advice on how to define such variable, Tp?

P.S. I have tried to define Tp=Tp*(T<Tp)+T*(T>Tp), but Comsol shows "circular variable dependency detected" and cannot compute

Many thanks & warmest regards,
Jie



2 Replies Last Post 23 sept. 2013, 05:16 UTC−4
Edgar J. Kaiser Certified Consultant

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 20 sept. 2013, 08:52 UTC−4
Hi,

you can use a maxop model coupling for that. You find it under model > definitions > model couplings.

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
Hi, you can use a maxop model coupling for that. You find it under model > definitions > model couplings. Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 23 sept. 2013, 05:16 UTC−4

Hi,

you can use a maxop model coupling for that. You find it under model > definitions > model couplings.

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology


Dear Edgar,

Thanks for your reply, but I think you misunderstood my problem. Your method is to find the maximum value within the domain for all the points. But my problem is to find maximum value of each point for all the time.

Best wishes,
Song J.
[QUOTE] Hi, you can use a maxop model coupling for that. You find it under model > definitions > model couplings. Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology [/QUOTE] Dear Edgar, Thanks for your reply, but I think you misunderstood my problem. Your method is to find the maximum value within the domain for all the points. But my problem is to find maximum value of each point for all the time. Best wishes, Song J.

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.