Mainly, the idea is to capitalize on the idea of a whirlpool in a tank. If you put a divider in the tank then you get nearly-laminar type flow (or whatever the right term is) on each side of the divider. So, say if you had a platform style divider, you could build the reef on this part, but hide your powerheads in the bottom part, use a wavemaker and then you have something I bet the corals would totally dig.
try this link for some reading (hopefully it jumps forward to the right section, if not, just search on "gyre"):
http://www.advancedaquarist.com/2007/1/aafeature#h5