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.






Yes. It’s not necessarily the size that makes the noise, but rather the rpm required of the smaller fans to move an equivalent amount of air. I have a fan in my phone, for instance. It is so small that it spins at 23,000 rpm to make just a small amount of air movement I can barely feel, but easily hear. My ceiling fan can’t be heard at all but still moves WAY more air while spinning at a couple hundred rpm. The air turbulence from blade speed is most of what you hear from a fan.