Venturi Flume vs Weir | Difference between Venturi Flume and Weir

This page compares Venturi Flume vs Weir and mentions difference between Venturi Flume and Weir.

Venturi Flume

Venturi Flume

• It is critical flow open flume with constricted flow. This causes drop in hydraulic grade line which creates critical depth.
• Venturi flume is used for very large flow rate measurements, usually in units of millions of cube.
• Venturi Flume measures in meters unlike venturi meter which measures in millimeters.
• Measurement of discharge with venturi flume requires two measurements viz. one at upstream and the other at throat (i.e. at narrowest cross-section).


Weir working

• It is a barrier across flowing fluid which is designed to alter flow characteristics.
• It is used to prevent flooding, to measure discharge and to render river navigable.
• It takes forms of obstructions which are smaller compare to conventional dams.
• Geometry of top of weir as well as water flows over it are known. Hence depth of water behind weir can be converted into rate of the flow.
• Discharge can be summarized as follows.
Q = C*L*Hn
• Weir crest should be free of rust or impurities to have accurate flow measurement.
• Types of weirs include Labyrinth weir, Broad crested weir, Sharp crested weir, Compound weir and V-Notch Weir.

Following table summarizes core difference between Venturi Flume and Weir.

Features Venturi Flume Weir
Hydraulic Head Loss Less More
Dead Zone Does not exist (where debris/sediment accumulate) Exists (upstream of the weirs)
potential energy difference Does not exist Exist
Suitability for unclean waste water It can be used. It can not be used.

What is difference between or comparison between

Following links mention difference or comparison between various equipments and terms:
comparison between SPI and I2C
difference between PXI and PCI
Microscope vs Telescope
Amplitude Modulation vs Angle Modulation
difference between modem and router
Air Fuel Ratio Sensor vs O2 Sensor
Radiometer vs Spectrometer vs Spectroradiometer
Clamp meter vs digital multimeter
Colorimeter vs Spectrophotometer
difference between Prism and Grating
difference between Venturi meter and Orifice meter
difference between Lux and Lumens