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Periodic heat flux

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Hi everyone,

I have a simple 2D geometry (consider a rectangle) and I want to set one of the boundary conditions to be a periodic heat flux with a square waveform. Currently, I've set the inward flux expression to the following:

20000*(flc2hs(mod(t,0.002)-0.0001,1e-9)-flc2hs(mod(t,0.002)-0.0005,1e-9))

When I plot this expression under functions, it shows me exactly what I want, a square wave with a 400us width and a 2ms period. However, when I solve the problem, the results don't reflect a periodic wave, just a single pulse. I know this because I solved the problem for a single pulse of 400us width, and the solution is exactly the same.

What I would like to know is how to setup the heat flux using COMSOL's built in periodic boundary conditions. I tried following the help guide, but it is very confusing to me and I was hoping someone here might be able to help. Thanks

David

0 Replies Last Post 10 giu 2010, 16:27 GMT-4
COMSOL Moderator

Hello David Lai

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