Flow in Pipe and Open Channel

• The flow in pipe or open channel can be calculated by using Chezy formula . 
• V-C root mi
• where c= chezy constant 
• v= velocity of flow (m/s)
• m - hydraulic mean depth (m ) 
• i = invlination of fall 
• The hydraulic mean depth ( m ) = (cross section area of flow ) / ( length of wetted perimeter ) 
• The chezy constant may be calculated from the following formula. 
• where g - acceleration due to gravity ( 9.81 m/s square ) 
• F= coefficient of friction ( normally taken as 0.0064 ) 
• Thus C= Root  2x 9.81 / 0.0064 = 55

Example 2
E-5-2 . Using chezy formula , calculate the discharging capacity of a 200mm diameter sewer pipe flow full when laid to a fall of 1 in 200 ( 1:200 ) . ( C taken as 55 )
Example 3
E-5-3. A 150mm diameter sanitary pipe is required to discharge 151/s of waster water to a sewer main,  using chezy formula , estimate the minimum gradient required for the full flow . ( C taken as 55 )