It's just some standard fluid dynamics. It uses "Bernoulli’s Principle" and the "Coanda Effect".

You can look up those, or probably look up those along with "dyson bladeless fan" to find a more direct explanation. The gist of it is that the ring of moving air causes a pressure drop inside and behind the opening that causes the air from further behind the ring to rush into the low pressure area and get pulled along through it.