Venturi tube

Venturi tube

The complete setup of a Venturi tube and a set of manometers and static taps to measure static pressure. Holes have been drilled into the walls of the tube to measure the static pressure. The block diagrams below the tube show the interchange of dynamic and static pressures all along the tube. The conclusion drawn from this is that the static pressure decreases in the region of high-speed flow and increases in the region of low-speed flow.

A Venturi tube is a short open-ended pipe with a central constriction used for measuring the flow rate of a fluid. The fluid velocity increases and its pressure drops in the constriction. The fluid velocity is calculated from the pressure difference between the center and ends of the tube.