A Parshall flume is described as a Venturi-type device.

A Parshall flume is described as a Venturi-type device.

• A. Orifice
• B. Submerged nozzle
• C. Venturi
• D. Weir requiring free-fall discharge

Answer: (C)

A Parshall flume uses a converging throat that accelerates the flow and creates a measurable pressure (head) change, just like a Venturi meter. In open-channel flow, this Venturi-like constriction lets the discharge be determined from the relationship between the water level upstream (and at the throat) and the known geometry, so the device is described as Venturi-type. It’s not simply an orifice because it isn’t a flat plate in a pipe with a small hole; the Parshall has a shaped throat and upstream chamber designed for stable, open-channel flow and a defined head-discharge relationship. It’s not a submerged nozzle or a free-fall weir, which describe different flow measurement mechanisms.

A Parshall flume uses a converging throat that accelerates the flow and creates a measurable pressure (head) change, just like a Venturi meter. In open-channel flow, this Venturi-like constriction lets the discharge be determined from the relationship between the water level upstream (and at the throat) and the known geometry, so the device is described as Venturi-type. It’s not simply an orifice because it isn’t a flat plate in a pipe with a small hole; the Parshall has a shaped throat and upstream chamber designed for stable, open-channel flow and a defined head-discharge relationship. It’s not a submerged nozzle or a free-fall weir, which describe different flow measurement mechanisms.