Assertion: vortex ring | /r/HasProperty | noticed
Facets:
value: rarely
type: DEGREE
value: as in the smoke rings
type: LOCATION
Source sentences:
text: Vortex rings are plentiful in turbulent flows of liquids and gases, but are rarely noticed unless the motion of the fluid is revealed by suspended particles—as in the smoke rings which are often produced intentionally or accidentally by smokers.