Perforated plated is commonly used in Tel-communication equipment. When you want a thermal simulation in Cosmos floworks (CF), you'll find it is hard to describe it directly with exist model like icepak or flotherm.

In icepak, "grill" model, a kind of planar resistance, used to simulate perforated plate. Of course, flotherm has its own "perforated plate" model.

How we deal with it? EFD, CF's older sister provided "perforated model", but this kind model can defined on the conditional surface only. Conditional surface means the surface been defined the velocity or pressure. So, it's hard to apply on the perforated plate under natural convection.

Fortunately, icepak provide the formula of "grill" model, we can use it on CF!

Let's back to CF. Porous media in CF used to simulate the hydraulic resistance. And you can find the “screen material” inside the engineering database; it’s also a planar resistance. But you need provided the coefficient “A” and “B” manually. Right, look at the fig below, it’s how to calculate the round holes perforated plate.

I make a Solidworks Macro, this little program can calculate the coefficient for round/rectangle and hexagon holes. you can find it at (http://cid-308505520ccbd84a.skydrive.live.com/browse.aspx/Public)

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