venturi

Imagine water flowing through a pipe that suddenly gets narrower, then widens again. That specially narrowed section is called a venturi. As liquid or gas passes through the tight part, it speeds up and the pressure drops. That pressure drop can be useful for many jobs, from measuring flow to pulling another fluid along with it. Older carburetors are a classic example, and some sprayers and mixing systems use the same idea. The term comes from Giovanni Battista Venturi, an Italian physicist who studied this effect.

A venturi is a specially designed part of a pipe, tube, or channel that narrows and then widens again. It is used to control or measure the flow of a fluid, whether that fluid is a liquid or a gas. When the fluid moves through the narrow section, it speeds up and its pressure drops. This is the basis of the venturi effect.

This simple design has many practical uses. Engineers use venturis to measure flow rates because the pressure difference across the narrow section can show how much fluid is moving through a system. In older engines, carburetors used this pressure drop to help pull fuel into the air stream. Similar ideas are used in atomizers, injectors, and other devices that mix fluids or create suction.

The word comes from Giovanni Battista Venturi (1746-1822), an Italian physicist known for his work on fluid motion. Over time, his name became attached both to the narrowed tube shape and to the pressure-drop effect connected with it.

So when you hear about flow measurement, suction, or fluid mixing, think of a venturi: a narrowed passage that changes speed and pressure in a useful way.