Employed as a Sub-Surface Pulse Generator or Oscillator.
Radiating upward sub-surface expansive pulses manifesting as waves at the medium boundary . (Water/Air Surface).
If contained within a circular housing with a soft boundary, (which means that the wave medium (water) is free to move and not anchored at the reflective surface). In phase additive reflections from the soft boundary will result in conical standing waves at water air boundary..
If fully enclosed within a water filled housing the pressure pulses will be entirely subsurface and obviously will not manifest as visible water/air boundary waves. However the sub-surface pressure pulses and resultant standing waves will still be present.
It would be bi-directional.
It would oscillate and resonate at a narrow bandwidth enabled by the matched and projected replication of the inner and outer lobe curves, probably producing a sinusoidal waveform. Unmatched lobe curves would produce pulse frequencies over a broader range, (Broadband). The frequency of which is determined by rotational speed and housing/tank dimensions.
The rim serves as a synchronous rotating boundary/barrier to attenuate unwanted reflection from the inactive (open) but physically unavoidable area of the lobe segment.
Edited 4 time(s). Last edit at 06-Mar-18 13:19 by Jon Ellison.