# Discussion Forum

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.

## manually changing temperature values at specified time

Hi,
I am wondering if it is possible to change the temperature of a subdomain at a chosen time. And in addition to this, can the specified temperature be taken from another subdomain within the model?

For example, I have two blocks (A and B). A starts at 1600 K and is being cooled and at t = 60, I want the temperature of block B to equal that of block A at t = 60. I don't have need to have the exact same gradients (the average temperature is fine).

3 Replies Last Post Mar 17, 2010, 6:57 a.m. EDT

Hi

For me you have two questions in there:

1) change the temperature at given times: yes why not try

T = T0*(t<t0)+T1*(t>=t0)*(t<t1)*...*Tn*(t>=tn)

or otherwise simpler: define a piecevise function fT(t) and say T=fT(t)

2) couple the temperature between two items, or model at given times

Well why at given times ? why not express a continously linked physics and solve them together ?
There are a few examples in the doc about the weak constraints and boundary integrations, probably this is a good example for the non-ideal weak contraits (single way link), even an example somewhere about a thermal case with the temperature of one border linking around onto the other.

If not I would try to play with some integration variables over the domain to measure and then use the equation above for the controlled domain, but one must add some "*at(ti)" where "ti" are some of the PREVIOUS solved time steps to get it to work. But I'm not sure this (the "at()" operator) would even work during the simulation, you would have to test it out carefully, never done something like that

Hope this helps
Good luck
Ivar