Hydraulic Profile Calculations
Ref: Sincero and Sincero, Environmental Engineering: A Design Approach; 1996.
Prentice Hall. p. 346.
1. Start at the discharge point, since the receiving water elevation affects the hydraulic
profile
2. Calculate back through diffuser manifolds, supply pipe, chlorinator, etc. up the
flowsheet of the treatment plant
apply the energy equation
calculate head losses along the water flow path
(open channel flow, pipe and joint calcs, etc.)
look in your fluid mechanics books if you can’t remember!
please include references for your head loss equations
be sure to distinguish between pipe flow and open channel flow equations
example: Munson, Young, Okiishi. Fundamentals of Fluid Mechanics. 1990.
pipe flow head loss: hL = f l V2 / 2Dg f=friction factor; l = pipe length; V = ave velocity;
D = pipe diameter; g = gravity (for fully developed, steady, incompressible flow)
friction factor depends on roughness of pipe, which depends on pipe material
Valve head loss: hL = KL V2 / 2g where KL is the loss coefficient
KL values for different types of valves, tees, elbows, bends, etc. can be looked up
in tables (such as Table 8.3 in the Munson et al. text)
Open Channel Information: Bendient & Huber, Hydrology and Floodplain Analysis
Open channel head loss: hL = L ( n Vm / 1.49 Rm2/3)2 R = hydraulic radius; n =
Manning’s roughnes coefficient