I want to simulate a block of aluminum that has a certain temperature and radiates to an empty space. So I set up a COMSOL simulation:
Physics: heat transfer in solids, time dependent
I created a simple block
added a material (Aluminum 6063-T83)
set the temperatures (delta is 10K)
turned on surface-to-surface radiation
all surfaces of the block are diffuse surface with a given epsilon of 0.5
mesh is physics controlled (coarser)
When I do so I get reasonable results (I verified them by hand), but I noticed some kinks in the temperature plot. I investigated that they result from even bigger kinks in the ntfluxInt global value (see graph). I already varied the mesh sizes, time steps, material, and several other parameters, but none of that removes the kinks.
So my question is: where do these kinks come from? Are they simulation errors? Is there any way to get rid of them?
Thanks for your help