Vortex shedding flow meters are devices used to measure the flow of fluids like gases, liquids, or steam. They operate based on the principle of vortices forming behind a bluff body placed in the fluid flow path. As fluid passes by the bluff body, vortices alternate on either side, creating a shedding pattern. Sensors detect these vortices, and by measuring their frequency, the flow rate of the fluid can be determined.