Elmer Discussion Forum

Hi everyone,

I have a small problem computing viewfactors in an axi symmetric modell. When I use 2D cartesian coordinates everything works as expected. When I change the coordinate system to axi symmetric, all the view factors a zero.

Is there a reason for this behavior?

Best,

carsten

Hello,

Elmer offers the possibility to use cylindrical as well as axi symmetric coordinate systems.

What is the difference between both?

Cheers,

carsten

Hello, I am currently using Elmer for thermal simulations of bodies in close proximity at high temperatures with open surroundings. The basic mechanism for coupling of the different bodies is radiation. I performed several simulations in 2D and the results are very promising. Unfortunately, the resu...

Hi Cesar, Hi Peter, the advice to omit the newton iteration did the trick, the simulation did converge (but I am a little confused since I thought until now that the newton-rhapson method has better convergence properties than the picard iteration). The structure with the cylinders was just a test c...

Ok, I modeled the same setup with every volume body as seperate group and every surface as distinct boundary group an I still get the same strange behavior of NaN in the fourth itteration.

Any other suggestions?

Best!

Hi mzenker,

thanks for trying I modeled all cylinders as one body since I only have one material and one boundary condition so I guess this should work.

Cheers,

Carsten

Hello everyone, I tried modeling the thermal coupling of several bodys in vacuum in Elmer. I started rather simple with a few cylinder with high thermal conductivity, internal heat source (body force) and diffuse radiation boundary conditions. The simulation works in principle quiet well unless I pl...