Parshall Constants Calculator

The Concept of Deriving Parshall Channel Constants (C and m)

The constants C and m for Parshall channels are not derived directly from theoretical principles of fluid mechanics for each channel size; instead, they are the result of an exhaustive process of experimental and empirical research.

Important notes:

Non-standard values:
- Values for W < 3" or 7.62 cm are theoretical extrapolations and are not supported by official standards. Parshall flumes for W < 3" are rare in practical applications due to accuracy limitations in low flow measurements. Values for W ≥ 3" were obtained from "JM De Azevedo and Guillermo Acosta (1976) Manual de Hidráulica" and from the Mexican standard "NMX-AA-179-SCFI-2018"
Recommendation:
- If you need to use a Parshall flume for W < 3", consider performing an experimental calibration (secondary method) or using alternative technologies (such as triangular-crested weirs).

What is a Parshall Flume?
The Parshall flume, also known as a Parshall meter, is a hydraulic structure used to measure flow in open channels. It was developed by Ralph L. Parshall in the 1920s and has become a standard tool in hydraulic engineering due to its accuracy and ease of use. This device is characterized by its specific shape, which includes a convergent section, a narrow throat, and a divergent section, allowing the flow rate (Q) to be calculated from the depth measurement (h).

Parshall Flume Constants and Flow Calculator
Do you need to calculate the C and m constants for a Parshall flume? Or determine the flow rate Q quickly and accurately? Our Parshall Flume Constants Calculator is the perfect tool for you! With an intuitive and easy-to-use interface, this calculator allows you to:

Calculate the constants C and m: Enter the throat width (W) and obtain the constants needed for the flow rate formula.
Determine the flow rate (Q): Enter the hydraulic head (h) and calculate the flow rate in cubic meters per second (m3/s).
Accurate results: Uses linear interpolation to get accurate values, even if the throat width does not match the values in the table.

This tool is ideal for hydraulic engineers, students, and professionals working with Parshall flumes. Streamline your calculations and save time with our online calculator!

To calculate flow only and learn more about Parshall visit our other resources:

Parshall Calculator