Discussion Forum

Hi,

I am using COMSOL 4.3b and my model is a simple cube where I specified a heat source as having two different values. For my goal purposes, I am doing a time-transient study where from 1s to 2s heat source value is A, from 2s to 3s is B, from 3s to 4s is A again and so on. I am switching between A and B every second. I managed to implement this correctly by changing the option "steps taken by solver" and select a time step of 0.5s. All of this works fine when the geometry is simple (as it is for the cube), however now I want to implement the same thing for a much more complex geometry. The problem is that to simulate just 10s (which corresponds to 20 simulations due to the time step) it takes me about 3 hours for this geometry. I want to simulate several hours which is unfeasible. My questions are 1) if a specify some time-steps to solve my problem (for example every 2 min) how can I tell COMSOL that the value of the heat source is changing every second without specifying the time-step? Because if I do not specify it COMSOL does not take this heat source value variation in consideration. I saw this in the log file where I can see the time-steps taken by the solver. 2) If I specify a certain time-range that does not start at 0s but starts for example at 10 min, how does COMSOL knows the values of former times that are necessary to know the temperature field at t=10min?

Thanks in advance.

Kind regards, Nichal