Chezy Formula Calculators

The Chezy formula is often used in open-channel hydraulics to estimate the velocity of flow, and it’s closely tied to factors like channel roughness and slope. Here’s a breakdown of the different calculations:

1. Mean Velocity: The mean velocity in an open channel flow can be calculated using the Chezy equation, which relates the flow velocity to the hydraulic radius, slope, and Chezy coefficient.

   Formula:
   

   Where:

   • V = Mean velocity of flow (m/s)
   • C = Chezy coefficient (m½/s)
   • R = Hydraulic radius (m)
   • S = Slope of the channel (dimensionless)

2. Chezy Coefficient: The Chezy coefficient C represents the roughness of the channel and is an empirical value, often determined based on the material or texture of the channel bed. You can rearrange the Chezy equation to solve for C if you know the mean velocity, hydraulic radius, and slope.

   Formula:
   

   Where:

   • V = Mean velocity (m/s)
   • R = Hydraulic radius (m)
   • S = Slope of the channel (dimensionless)

3. Hydraulic Radius: The hydraulic radius is the ratio of the cross-sectional area of flow to the wetted perimeter. It is a key factor in determining the flow velocity in the Chezy equation.

   Formula:
   

   Where:

   • A = Cross-sectional area of flow (m²)
   • P = Wetted perimeter (m)

4. Slope: The slope SS S is the ratio of the vertical drop (elevation change) to the horizontal distance of the flow. It influences the velocity of flow in open channels.

   Formula:
   

   Where:

   • Δh= Change in elevation (m)
   • L = Horizontal distance (m)

How to use:

If you have specific values for any of these variables, you can use the formulas above to solve for the others. For example:

• If you know the flow velocity V, hydraulic radius R, and slope S, you can calculate the Chezy coefficient C.
• If you have C, R, and S, you can calculate the mean flow velocity V.