Chezy Coefficient

on . Posted in Fluid Dynamics

The Chezy coefficient, abbreviated as C, a dimensionless number, also called the Chezy roughness coefficient or Chezy's resistance coefficient, is used in open channel flow to characterize the roughness of the channel bed and the resistance to flow.  The Chezy coefficient is often determined through empirical relationships or calibration with field data.  It is used in hydraulic engineering and river management to estimate flow velocities, water levels, and discharge rates in open channel flows.  The selection of an appropriate Chezy coefficient depends on the specific conditions of the channel, including its roughness characteristics, material, and geometry.


Chezy coefficient formula

\( C = ( 1 \;/\; n ) \; r_h^{1/6} \)     (Chezy Coefficient)

\( n = (1 \;/\; C ) \; r_h^{1/6}  \)

\( r_h =  ( C \; n )^6  \)

Solve for C

roughness coefficient, n
hydraulic radius, rh

Solve for n

Chezy coefficient, C
hydraulic radius, rh

Solve for rh

Chezy coefficient, C
roughness coefficient, n

Symbol English Metric
\( C \) = Chezy coefficient \( dimensionless \)
\( n \) = roughness coefficient \( dimensionless \)
\( r_h \) = hydraulic radius \( ft \) \( m \)


 P D Logo 1

Tags: Coefficient Open Channel Roughness