How does a vortex flow meter work and what are its applications?

Vortex flow meters contain a bluff body (shedder bar) that creates alternating vortices (Von Karman vortex street) at a frequency proportional to flow velocity. Piezoelectric or capacitive sensors detect vortex frequency. They work with liquids, gases, and steam; have no moving parts; wide turndown ratio (20:1); and require minimum Reynolds number (typically >10,000). Not suitable for low-velocity or viscous fluids. Commonly used for steam flow measurement.