A study on signal quality of a vortex flowmeter downstream of two elbows out-of-plane

Experiments were made with a vortex meter situated downstream of two elbows out-of-plane, at Reynolds numbers between 7.8 × 10⁴ and 2.1 × 10⁵. Analysis on the signals obtained from a piezo-electric sensor embedded in the vortex shedder shows that the signal quality, concerned with the vortex shedding frequency component, deduced in the vicinity of 15 pipe diameters downstream is superior to that at other locations, and is remarkably better than that found in the region of fully-developed turbulent pipe flow. The vortex shedding frequencies measured in this region, in terms of the Strouhal value, fall within 0.129 ± 0.001, that 0.129 is the reference value reduced in the fully-developed turbulent pipe flow region. Also noted, the uncertainty interval associated with the vortex shedding frequency measured in this region is smaller than that reduced in the region of fully-developed turbulent pipe flow.