Vortex Shedding from a Ring and an Application to a Vortex Flowmeter

This paper is concerned with vortex shedding from rings and an application of this phenomenon to a vortex flowmeter for pipe flow.Vortex rings shed alternately from the inside and outside of a ring rotate opposite to each other and form stable vortex rows on the common axis of symmetry. The configulation of the rows is found to be different from that of Karman vortex street, that is, the spacing between the alternating vortices is not equal. Characteristics of vortex shedding from rings with various shapes are also experimentally investigated.Vortex shedding from a ring in pipe flow is not disturbed by the existence of the wall of the pipe and axisymmetrical velocity profile. The frequencies of vortex shedding from a ring can be detected more stably at the behind of the center of the ring comparing to vortex shedding from a plate. Thus, a ring is thought to have advantages as a bluff body of a vortex flowmeter for pipe flow.