An Acoustically Driven Vortex Cannon

The vortex cannon is a physics demonstration in which an impulse of air is pushed through an orifice in the end of a cylinder, resulting in a well-defined ring that travels subsonically through the air.   We developed a vortex cannon driven by a subwoofer and a sawtooth waveform.  Using a fog machine, we were able to generate 8-10 smoke rings per second.  The design of this demonstration was described in The Physics Teacher (see #101 in Publications).

Here is high-speed video of a vortex being generated: VortexRing.avi