I'm working on a project that requires concentrating air flow into a beam such that it can travel longer distances through an unconstrained medium (i.e. open space, not a hose).
Something that came to mind are those little air nozzles that you find on air planes. These seem to do a pretty good job of directing air through a narrow path such that it doesn't effect nearby passengers.
What kind of mechanism is used to maintain this tight air flow?