Internal Flow and Symmetry - can it be done?~ If so, how?

I’m modelling an electronics enclosure that has two identical heat-sinks mirrored on the central plane of the enclosure. I’m happy that modelling 1/2 the case standalone by inserting a dummy ‘wall’ gives near identical results to a full simulation as the two heat-sinks are well separated, but I’m less convinced that modelling two halves of the same heat-sink (also a mirror image but joined together) is possible that way.

Can I use symmetry somehow with internal flow? How do I ‘close the gap’ to create the flow region?

Hey Irving,

Maybe you can link your model or post some images for us to visualize the situation and the symmetries.

Here’s a view of the 1/4 model. Symmetry of the individual heat-sink is on the RH edge, and then the whole thing is mirrored as in the second image below (top view)


I’ve run simulations on the 1/4 model with symmetry using an external flow model restricted to the case boundary but I’m not sure that the best way. I’d like to run with the internal flow model as intuitively that’s a better fit, but modelling the whole is much slower. As I said previously, modelling on heat-sink with a dummy ‘case wall’ on a 1/2 model gives similar results to modelling the whole, though, as expected, the airflow is not the same close to the dummy wall as in the full model. It doesn’t seem to have too detrimental effect as heat-sink temperatures appear similar within 0.5degC. However I don’t think using a dummy wall on the other symmetry plane will work well, so can I use symmetry with an internal flow model?