A Venturi flowmeter is based on which principle?

A Venturi flowmeter is based on which principle?

• A. Magnetic induction
• B. Flow measurement by turbine speed
• C. Bernoulli's principle with differential pressure
• D. Acoustic resonance

Answer: (C)

Venturi flowmeters rely on Bernoulli's principle combined with continuity. When the fluid flows into the constricted throat, its velocity must increase to keep the same mass flow, so the static pressure drops at the throat. By measuring the pressure difference between the upstream side and the throat with taps, you obtain a differential pressure that relates to how much fluid is moving. Using Bernoulli’s equation (and known fluid density and the pipe geometry), that differential pressure is converted to a flow rate. This method has no moving parts and works well for liquids like wastewater. The other options aren’t the basis for a Venturi meter: magnetic induction uses a magnetic field and fluid conductivity to infer flow, a turbine meter relies on a rotating turbine driven by the flow, and acoustic resonance uses sound waves to gauge flow.

Venturi flowmeters rely on Bernoulli's principle combined with continuity. When the fluid flows into the constricted throat, its velocity must increase to keep the same mass flow, so the static pressure drops at the throat. By measuring the pressure difference between the upstream side and the throat with taps, you obtain a differential pressure that relates to how much fluid is moving. Using Bernoulli’s equation (and known fluid density and the pipe geometry), that differential pressure is converted to a flow rate. This method has no moving parts and works well for liquids like wastewater.

The other options aren’t the basis for a Venturi meter: magnetic induction uses a magnetic field and fluid conductivity to infer flow, a turbine meter relies on a rotating turbine driven by the flow, and acoustic resonance uses sound waves to gauge flow.