Karman Vortex formation is a natural phenomenon occurring in the wind paths in natural. This natural phenomenon can be created artificially by placing an obstruction in fluid path.
Eddies or vortices are formed at the surface of this bluff body. When a vortex on one side of the bluff body breaks away from the body, it is followed by a new one on the opposite side of the body.
That in turn also breaks away, followed by a new vortex on the opposite side. This alternate shedding of vortices is the basis of meter operation.
Shedding vortices create attenuating pressure on the shedder bar. This pressure acts on the bar in the form of stress. Piezoelectric elements of the sensor are embedded inside the metal bar of the vortex shedder protected from the process flow.