To determine Chezy’s and Manning’s coefficient (C and N) for a rectangular smooth open channel.

Object: To determine the Chezy’s and Manning’s coefficient (C and N) for a rectangular smooth open channel.

Apparatus Required:

• Perspex–sided S4 tilting flume, with slope control device; stopwatch.
  

Perspex-sided tilting flume S4

Theory:

Fig. Uniform Flow in an Open Channel

In uniform flow:

Y is constant V is constant

Sw = Sf = So = S (common symbol) For a rectangular channel,

A = BY

P = B + 2Y R = A / P

Fig. Cross-section of a rectangular channel

For uniform open-channel flow, Chezy’s formula:

V  C

R S

(1.1)

C V

RS

(1.2)

And Manning’s formula:

V  1 R 2 / 3 S 1 / 2

n

(1.3)

n 

R 2 / 3 S 1 / 2

V

(1.4)

Procedure:

2

Results & Comments: