63
If the fluid is partially occupying the pipe, leaving other portion filled with air at
atmospheric pressure, then one has to apply theory of channel flow (Figs. 2.7 and
2.8) discussed later in this chapter.
Conventionally, for calculation with respect to flow in channel, Chézy formula or
Manning’s equation is used.
Chézy Formula
v C Ri
=
Where
v = average velocity
C = Chezy coefficient
R = hydraulic radius =
Cross sectional area
Wetted perimeter
−
i = hydraulic gradient
Manning’s Equation
Q
KAR S
n
=
2 3 1 2
/
/
Where
Q = flow rate
A = cross-sectional area of flow
R = hydraulic radius =
Cross sectional area
Wetted perimeter
−
Fig. 2.8 Flow in river around bodies
2.4 Fluid Mechanics
If the fluid is partially occupying the pipe, leaving other portion filled with air at
atmospheric pressure, then one has to apply theory of channel flow (Figs. 2.7 and
2.8) discussed later in this chapter.
Conventionally, for calculation with respect to flow in channel, Chézy formula or
Manning’s equation is used.
Chézy Formula
v C Ri
=
Where
v = average velocity
C = Chezy coefficient
R = hydraulic radius =
Cross sectional area
Wetted perimeter
−
i = hydraulic gradient
Manning’s Equation
Q
KAR S
n
=
2 3 1 2
/
/
Where
Q = flow rate
A = cross-sectional area of flow
R = hydraulic radius =
Cross sectional area
Wetted perimeter
−
Fig. 2.8 Flow in river around bodies
2.4 Fluid Mechanics