Agenda | General | Engineering | Hydraulic | Free flow


Flow conditions:

Fr < 1    Sub critical flow
Fr = 1    Critical flow
Fr > 1    Super critical flow

Q    Flow discharge [m³/s]
A    Wet area [m²]
P    Wet perimeter [m]
T    Surface width [m]
V    Flow velocity [m/s]
R    Hydraulic radius [m]
D    Hydraulic depth [m]
Fr    Froude number [-]
g    Gravitational acceleration [9.81 m²/s]


Energy equation (Bernoulli)


E    Total energy [m]
ΔH    Energy loss [m]
H    Water level [m]
h    Water height [m]
Z    Bottom level [m]
L    Flow line length [m]
V    Flow velocity [m/s]
g    Gravitational acceleration [9.81 m²/s]
S    Slope [-]


Energy loss

ΔH    Total loss [m]
ΔHF    Friction loss [m]
ΔHM    Minor losses [m]
L    Flow line length [m]
J    Unit friction loss [m/m]
K    Local loss coefficient [-]
V    Flow velocity [m/s]
g    Gravitational acceleration [9.81 m²/s]


Friction loss / Kutter formula

J    Unit friction loss [m/m]
A    Wet area [m²]
R    Hydraulic radius [m]
S    Slope [-]
b    Friction coefficient [-]
------------------------------
Concrete pipe    b=0.35
Plastic pipe    b=0.10


Friction loss / Manning formula

J    Unit friction loss [m/m]
A    Wet area [m2]
R    Hydraulic radius [m]
S    Slope [-]
n    Friction coefficient [-]
------------------------------
Concrete pipe    n=0.013
Plastic pipe    n=0.008