A Parshall flume is a type of

A Parshall flume is a type of

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

Answer: (B)

Parshall flume uses a Venturi-type flow measurement principle in open-channel flow. Its geometry includes a converging section that narrows to a throat, which accelerates the water and lowers pressure. The throat is connected to a vertical measuring tube (stiling well) that shows the pressure head corresponding to that throat flow. By knowing the relationship between that head and discharge, engineers can determine the flow rate through standardized Parshall equations. This Venturi-like constriction is the key reason it’s classified as a venturi-type device. It isn’t a weir, which measures flow by water spilling over an edge and depends on the upstream water level above the weir crest. It isn’t simply an orifice, which is a plate in a closed conduit and measures flow through a small pressure drop without the open-channel geometry and measuring tube. It also isn’t a submerged nozzle, which isn’t how Parshall flumes measure open-channel flow.

Parshall flume uses a Venturi-type flow measurement principle in open-channel flow. Its geometry includes a converging section that narrows to a throat, which accelerates the water and lowers pressure. The throat is connected to a vertical measuring tube (stiling well) that shows the pressure head corresponding to that throat flow. By knowing the relationship between that head and discharge, engineers can determine the flow rate through standardized Parshall equations. This Venturi-like constriction is the key reason it’s classified as a venturi-type device.

It isn’t a weir, which measures flow by water spilling over an edge and depends on the upstream water level above the weir crest. It isn’t simply an orifice, which is a plate in a closed conduit and measures flow through a small pressure drop without the open-channel geometry and measuring tube. It also isn’t a submerged nozzle, which isn’t how Parshall flumes measure open-channel flow.