Chezy's formula is used to determine :

Explanation:

Chezy’s Equation:

The Chezy equation can be used to calculate mean flow velocity in open channel.

The loss of head in pipes due to friction considering the wetted perimeter is given by:

\({h_f} = \frac{{f'}}{{\rho g}} \times \frac{P}{A} \times L \times {V^2}\;\;\;\;\;\;\;(1)\)

where hf = loss of head due to friction, f' = frictional resistance per unit wetted area per unit velocity, P = wetted perimeter of pipe, L = length of pipe

A = area of cross-section of pipe and V = mean velocity of flow.

Hydraulic Mean Depth (m):

It is the ratio of the area of flow to the wetted perimeter of flowing fluid. It is given by-

\(m=\frac{Area\;of\;flow}{Wetted\;perimeter}\Rightarrow\frac{\frac{\pi}{4}d^2}{\pi{d}}=\frac{d}{4}\)

Rearranging the above equation (1):

\({V^2} = \frac{{\rho g}}{{f'}} \times \frac{A}{P} \times \frac{{{h_f}}}{L}\)

\(V = \sqrt {\frac{{\rho g}}{{f'}} \times m \times \frac{{{h_f}}}{L}} \)

\(V=\sqrt {\frac{{\rho g}}{{f'}}} \times \sqrt {m \times \frac{{{h_f}}}{L}} \)

\(V = C\sqrt {mi} \)

\(where~i=\frac{h_f}{L}\Rightarrow Loss\;of\;head\;per\;unit\;length\;of\;pipe\)

\(C = \sqrt {\frac{{\rho g}}{{f'}}}\Rightarrow Chezy's\;constant\)