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BFC21103 Hydraulics
Chapter 4. Non‐Uniform Flow
in
Open
ChannelTan Lai Wai, Wan Afnizan & Zarina Md Ali
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Learning Outcomes
At the end of this chapter, students should be able to:
i.
Analyse the
characteristics
of
hydraulic
jump
(rapidly‐varied flow) based on momentum
equation
ii. Analyse the characteristics of gradually‐varied
flow
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Occurs when the depth of flow change rapidly within short distance,
e.g. hydraulic jump.
Hydraulic jump occurs when supercritical flow changes suddenly to
subcritical flow within a short distance.
Datum
BFC21103 Hydraulics
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4.1 Rapidly‐Varied Flow
2y
cy 1
y supercritical
1 2
subcritical
hydraulic
jump
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Hydraulic jump only occurs if the upstream flow is supercritical,
i.e. y 1 y c > y 1
where,
y 1 = depth
of
flow
just
before
the
jump
y 2 = depth of flow just after the jump
y 1 and y 2 are known as conjugate depths
4.2 Hydraulic
Jump
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Hydraulic jump in the laboratory flume
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Hydraulic jump at the toe of spillway ‐ Itaipu dam, Brazil
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Hydraulic jump downstream of sluice gate ‐ Harran canal, Turkey
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Waves hitting sea wall in Depoe bay, Oregon U.S.
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Surge waves due to fast flowing flood in Tangjiasan, China
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i. Energy dissipator i.e. reduce velocity and prevent erosion
ii. Diverse the
water
irrigation
iii. Increase weight of water
iv. Mix
chemical
substance
e.g.
in
water
treatment
processv. Aeration of flow, i.e. increase DO
Applications of
Hydraulic
Jump
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Based on the Froude number before the jump Fr1
Fr1 = 1.0 − 1.7 → undular jump
Fr1 = 1.7 − 2.5 → weak jump
Fr1 =
2.5 −
4.5 →
oscillating
jumpFr1 = 4.5 − 9.0 → steady jump
Fr1 > 9.0 → strong jump
Types of
Jump
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Fr1
= 1.6
Energy dissipation = 45% to 70%
Energy dissipation up to 85%
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Momentum Equation
Consider a hydraulic jump on a frictionless flat bed within a
rectangular channel,
12 MMF −=∑124321
QV QV F F F F ρ −=+−−
2y
1y
1 2
F 1
F 1
F 3
F 4
W
Since friction = 0 → F 3 = 0 and flat bed F 4 = W sinθ = 0
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12
2
2
1
122
QV QV y
gAy
gA ρ ρ ρ ρ −=−
1221 QV QV F F ρ ρ −=−
g
qV
g
qV y y 12
2
2
2
12
1
2
1−=−
Dividing by ρ
gB,
Since ,2
2
1
1
and y
qV
y
qV ==
1
2
2
2
2
2
2
12
1
2
1
gy
q
gy
qy y −=−
2
2
2
2
2
1
1
2
2
1
2
1y
gy
qy
gy
q+=+
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Activity 4.1
Using the
momentum
force
equation,
draw
the
specific
force
curve
if a hydraulic jump occurs within a rectangular channel with the
discharge per unit width is 25 ft3/s.
Given q = 25 ft3/s flows in a rectangular channel
2
2
21 y
gy qF +=Specific force is given as
Hydrostatic
pressure
Momentum
flux
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y (ft) F (ft2)
1.0 19.910
1.2 16.895
1.4 14.844
1.6 13.411
1.8 12.403
2.0 11.705
2.2 11.243
2.4 10.967
2.6 10.845
2.8 10.852
3.0 10.970
3.2 11.186
3.4 11.4893.6 11.872
3.8 12.328
4.0 12.852
4.2 13.441
4.4 14.091
4.6 14.800
4.8 15.564
5.0 16.382
5.2 17.253
5.4 18.174
5.6 19.146
5.8 20.167
0
1
2
3
4
5
6
0 5 10 15 20
y (ft)
F (ft2)
y c
Subcritical flow Fr 1
F min
y 1 and y 2 with the same F are conjugate depths
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Conjugate Depths Equation
From the momentum equation of flow in a rectangular channel,
2
2
2
2
2
1
1
2
2
1
2
1y
gy
qy
gy
q+=+
2
2
1
2
2
1
2
2
22
gy
q
gy
qy y −=−
( )( ) ⎟⎟ ⎠
⎞⎜⎜⎝
⎛ −=+−21
12
2
2112
2
y y
y y
g
qy y y y
( ) g
qy y y y
2
2121
2
=+
Rearranging,
It can be seen that Fr can be introduced since3
2
2Frgy
q=
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( )3
1
2
2
1
2
21
2
gy
q
y
y y y =+Division by ,31y
2
1
1
2
2
1
2
2 Fr2=+y
y
y
y
0Fr2 2
1
1
2
2
1
2
2 =−+y
y
y
y
Solving for gives1
2
y
y
Note that
solving
gives
02 =++ cbx ax
a
acbb x
2
42 −±−
=
since y 1 and y 2 are positive values
( )( )
( )12
Fr21411 2
1
2
1
2 −−+
−=y
y
( )21
1
2 Fr8112
1++−=
y
y
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Else if division is made by ,32
y
2
Fr811 2
2
2
1 ++
−=y
y
Note that for hydraulic jump to occur, or 11
2 >y
y 12
1 <y
y
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Energy Loss
There will be considerable loss of energy in hydraulic jump between sections 1 and 2
Datum
2y
cy
1y supercritical
1 2
subcritical
hydraulic
jump
E o
g
V
2
2
2
g
V
2
2
1
EGLE L
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Energy
loss
is
calculated
as 21 E E E L −=
⎟ ⎞
⎜⎝
⎛ +−⎟
⎠
⎞⎜⎝
⎛ +=
g
V y
g
V y E
L22
2
2
2
2
1
1
For rectangular channel, it can be simplified as
⎟⎟
⎞
⎜⎜⎝
⎛
+−⎟⎟
⎞
⎜⎜⎝
⎛
+=22
2
221
2
1 22 gy
q
y gy
q
y E L
( ) ⎟⎟
⎠
⎞⎜⎜
⎝
⎛ −+−=
2
2
2
1
2
21
11
2
1
y y g
qy y E
L
( ) ⎟⎟ ⎞
⎜⎜⎝
⎛ −+−=
2
2
2
1
2
1
2
2
2
212
1
y y
y y
g
qy y E
L
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( ) ( ) ⎟⎟ ⎞
⎜⎜⎝
⎛ −⎥⎦
⎤⎢⎣
⎡ ++−=2
2
2
1
2
1
2
2
2121212
1
2
1
y y
y y y y y y y y E
L
Substituting ( ) 2121
2
2
1
y y y y g
q
+=
( )
21
2
2
1
3
2
3
1
2
212121
4
4
y y
y y y y y y y y y y E
L
−+−+−=
21
3
1
2
212
2
1
3
2
4
33
y y
y y y y y y E
L
−−+=
( )21
3
12
4 y y y y E
L −=
which is expressed in meter
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Power due to Energy Loss
Power due to energy loss in unit Watt is given as
LL gQE P ρ =
Height of Jump
The height of jump is given as
12 y y H
j −=
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Length of Jump
Based on Froude number upstream of the jump Fr1,
( )12
9.6 y y L j
−=
21.6 y L
j =
for Fr1 ≤ 5.0
for Fr1 > 5.0
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Activity 4.2
A
spillway
discharges
flow
at
a
rate
of
7.75
m3/s/m.
At
the
downstream horizontal apron, the depth of flow was found to be
0.5 m. What tailwater depth is needed to form a hydraulic jump? If
a jump is formed, find its
(i) type;
(ii) length;
(iii)
head loss;
and
(iv) energy loss as a percentage of the initial energy.
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Given q = 7.75 m3/s/m, y 1 = 0.5 m
( )21
1
2 Fr8112
1++−=
y
y
999.65.081.9
75.7Fr
33
1
1 =
×==
gy
q
Utilizing the conjugate depths equation,
( )22
999.68112
5.0×++−=y
m705.42 =y
(i) Based on the Fr1 = 6.999, the jump is a steady jump (4.5
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(ii) Since Fr1 = 6.999 > 5.0
21.6 y L
j =Length of jump
705.41.6 ×= j
L
m70.28= j L
(iii)
Head loss
is
given
as
( )
21
3
12
4 y y y y E L −=
( )
705.45.04
5.0705.4 3
××
−=
LE
m901.7=L
E
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(iv) Initial total energy is 2
1
2
1o
2gy
qy E +=
2
2
o5.081.92
75.75.0
××+=E
m745.12o =E
Percentage of energy loss %99.61%100745.12
901.7
o
=×=E
E L
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Activity 4.3
A
25‐
m
wide
spillway
is
discharging
flow
with
velocity
of
30
m/s
at
adepth of 1 m. Hydraulic jump occurs immediately downstream. Find
the height of the jump and power loss due to the jump.
Given B =
25
m,
y 1 = 1 m, V 1 = 30 m/s
( )21
1
2 Fr8112
1++−=
y
y
578.9
181.9
30Fr
1
11 =
×==
gy
V
Conjugate depths equation,
( )22
578.98112
1×++−=y
m
055.132 =
y
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(i) Height of jump 12 y y H j −=
1055.13 −= j
H
m055.12= j
H
(ii) Energy loss ( )
21
3
12
4 y y
y y E
L
−=
( )055.12141055.12
3
××−=LE
m019.28=L
E
Power due to energy lossLL
gQE P ρ =
( ) 019.28301259810 ××××=L
P
MW
15.206=LP
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A steady non‐uniform flow in a prismatic channel with gradual changes
in its flow surface elevation.
Examples:
(i) Drawdown produced by sudden change in channel bed slope
4.3 Gradually‐Varied Flow
M2
S2y c
Mild slope
S t e e p s l o p e
y o
y o
control section
Computations C o m p u t a t i o n s
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(ii) Backwater produced by increased in bed elevation
M1
y cM i l d
s l o p e
y o1
control section 1
Computations ComputationsMilder
slope
y o2
Lake
control section 2
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Types of Slope
y o So Type of slope Symbol
y o > y c
or
So
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Classification of GVF ProfileChannel Region Condition Type
Mild slope
1 y > y o > y c M1
2 y o > y > y c M2
3 y o > y c > y M3
Steep slope
1 y > y c > y o S1
2 y c > y > y o S2
3 y c > y o > y S3
Critical slope1 y > y o = y c C1
3 y y c H2
3 y y c A2
3 y < y c A3
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Classification of GVF Profile
Slope Region 1 Region
2 Region
3
Mild M
Steep S
Critical C
M1
y o
y c
y > y o > y c
M2y o
y c
y o > y > y c
M3y o
y c
y o > y c > y
S1
y > y c > y o
y cy o
S3
y c > y o > y
y cy o
y c > y > y o
y cy o S2
C1
y > y o = y c
y o = y
c
C3
y o = y c > y
y o = y
c −
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Slope Region 1 Region
2 Region
3
Horizontal
H
Adverse A
H2
y c
y > y c
−
−
A2
H2y c
y c > y
y > y c
y c
y c > y
y c
All curves in region 1 have positive slopes (backwater curves)
All curves in region 2 have negative slopes (drawdown curves)
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Occurrence of Flow Profile
(a) i. M1 profile
Occurs due to obstruction to subcritical flow, e.g. weir, dam or
other control structures. The profile extends to several kilometres
upstream before
approaching
the
normal
depth.
M1
y o
y c
y > y o > y c
Mild slope
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(a)
ii.
M2 profileOccurs when there is a sudden drop in the bottom of the channel,
constriction of channel or channel outlet into reservoir.
M2
y o
y c
y o > y > y c
Mild
slope
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(a)
iii.
M3 profileOccurs when supercritical flow enters a mild slope channel, e.g.
flow from a spillway or a sluice gate to a mild channel.
M3y o
y c
y o > y c > y
Mild slope
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(b)
i.
S1 profileOccurs when supercritical flow changes to pool of water
(subcritical flow) due to obstruction such as weir or dam.
S1
y o
y c
Steep slope
y > y c > y o
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(b)
ii.
S2 profileOccurs when flow from reservoir enter a steep slope or when
there is a change from mild slope to steep slope. This profile is of
shorter length.
y c > y > y o
y cy o S
2
Steep slope
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(b)
iii.
S3 profileOccurs when flow from reservoir enter a steep slope or when
there is a change from mild slope to steep slope. This profile is of
shorter length.
S3
y c > y o > y
y cy oSteep slope
S3
y cy oSteep slope
S t e e p e r s l o
p e
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(c) C1 and C3 profiles
Highly unstable
and
rarely
occur,
(d) H2 and H3 profiles
Occurs when
the
bed
of
mild
slope
becomes
flatter.
There
is
no
region 1 since y o = ∞.
y > y o = y c and y o = y c > y
H2
y c
y > y c
H3
y c > y
Horizontal bedDrop
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(e) A2
and A3
profiles
Occurs when flow is on adverse slope, which is rare. These profiles
occurs within a short length.
A2
y c
y > y c
y c > y
Adverse slope
A3
Drop
Pool
Activity 4 4
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Activity 4.4
Determine the type of profile for the following flow.
Sluice gate
y o
y c
Sluice gate
y c
y o
(a) (b)
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Sluice gate
y o
y c
Sluice gate
y c
y o
(a) (b)
S3
S1
M3
M1
y c > y o → S
Zone 1 → S1
Zone 3 → S3
y o > y c → M
Zone 1 → M1
Zone 3 → M3
Activity 4 5
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Activity 4.5
A
rectangular
channel
with
bottom
width
4
m
and
bottom
slope
0.0008 has discharge of 1.5 m3/s. Along the gradually‐varied flow in
the channel, the depth at a section is found to be 0.3 m. Assuming
Manning n = 0.016, determine the type of GVF profile.
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Rectangular section, B = 4 m, So = 0.0008, n = 0.016, Q = 1.5 m3/s, y = 0.3 m.
2
1
o
3
2
S
Qn AR =
( )2
1
3
2
o
oo
0008.0
016.05.1
2
×=⎟⎟
⎠
⎞⎜⎜⎝
⎛
+ y B
By By
( ) 8485.024
443
2
o
oo =⎟⎟ ⎞⎜⎜
⎝ ⎛
+ y y y
m4261.0o =y
3
1
2
2
⎟⎟
⎞
⎜⎜⎝
⎛ =
gB
Qy
c
3
1
2
2
81.94
5.1⎟⎟
⎞⎜⎜⎝
⎛
×=cy
m2429.0=cy
2o M→>> cy y y Since
Activity 4.6
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Activity 4.6
A
triangular
channel
has
side
slope
1(H):1(V),
bed
slope
0.001,
and
Manning roughness n = 0.015. If rate of flow is 0.2 m3/s
(a) Determine the type of slope, and
(b) Give the limit of depths of flow in regions 1, 2, and 3.
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Triangular section, z = 1, So = 0.001, n = 0.015, Q = 0.2 m3/s
2
1
o
3
2
S
Qn AR =
( )2
1
3
2
2
o
2
o2
o
001.0
015.02.0
12
×=⎟
⎟ ⎠
⎞⎜⎜⎝
⎛
+ zy
zy zy
m5361.0o =y
g
Q
T
A
c
c
23
=
m3822.0=cy
Mslopemildo →> cy y Since
( ) 09487.022
3
2
o
2
o2o =⎟⎟ ⎞⎜⎜
⎝ ⎛
y y y
1897.038
o =y
( ) 81.9 2.02
232
=c
c
zy zy
008155.05 =cy
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m5361.0
:M
For 1 >y
m0.3822m5361.0 :M For 2 >> y
m0.3822
:M
For 3
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Analysis of GVF Profile
Two basic assumptions are involved in the analysis of GVF:
1. The pressure distribution at any section is hydrostatic.
2. The resistance to flow at any depth can be assumed using
uniform‐flow equation, such as the Manning's equation, with the
condition that the slope term to be used in the equation is the
energy slope
and
not
the
bed
slope.
Thus,
if
in
a GVF
the
depth
of
flow at any section is y , the energy slope S f is:
3
4
22
R
V nS f =
where R is the hydraulic radius of the section at depth y .
Differential Equation of GVF
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Differential Equation of GVF
The total
energy
H of
a gradually
‐varied
flow
in
a channel
of
small
slope is:
g
V y E
2
2
+=where the specific energy
g
V y zH
2
2
++=
Schematic sketch of GVF
E y
g
V
2
2
E ne r g y
l i ne
S f
W a t e r s u r f a c e
SozDatum x
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Since the water surface varies in the longitudinal x ‐direction, the depth
of the
flow
and
the
total
energy
are
functions
of
x .
Differentiating total energy with respect to x ,
⎟⎟
⎞
⎜⎜⎝
⎛
++= g
V
x x
y
x
z
x
H
2d
d
d
d
d
d
d
d 2
Energy slope
f
S x
H−=
d
d
Bottom
slope
oS x
Z −=
d
d
water‐surface slope
relative to the channel
bottom
x y
gAQ
x gV
x dd
2dd
2dd 2
22
⎟⎟ ⎞
⎜⎜⎝
⎛ =⎟⎟
⎞⎜⎜⎝
⎛
x
y
y
A
gA
Q
d
d
d
d3
2
−=
Velocity term
T A
=d
Since
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T y
=d
Since
x
y
gA
T Q
g
V
x d
d
2d
d3
22
=⎟⎟ ⎞
⎜⎜⎝
⎛
x
y
gA
T Q
x
y SS o f
d
d
d
d3
2
⎟⎟ ⎞
⎜⎜⎝
⎛ −+−=−
Differentiated energy
equation
can
now
be
rewritten
as
Rearranging,
3
2
1d
d
gA
T Q
SS
x
y f o
−
−= Dynamic
equation
of
GVF
Other forms of dynamic equation of GVF
( ) f d h d d
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BFC21103 Hydraulics
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(a) If K = conveyance at any depth y and K o = conveyance corresponding to
the normal
depth
y o,
then
f S
QK = for GVF
oS
Q
K =o for uniform flow
2
2
K
K
S
So
o
f =
If Z = section factor at depth y and Z c = section factor at the critical depth y c,
T
A Z
32 =
gQ
T A Z
c
cc
232 ==and
Hence2
2
3
2
Z
Z
gA
T Q c=
Substituting into the GVF dynamic equation
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g y q
⎟⎟⎟⎟ ⎞
⎜⎜⎜⎜
⎝
⎛
−
−=
3
2
1
1
d
d
gA
T Q
SS
S x
y o
f
o
⎥
⎥⎥⎥
⎦
⎤
⎢
⎢⎢⎢
⎣
⎡
⎟ ⎠
⎞
⎜⎝
⎛
−
⎟ ⎠
⎞⎜⎝
⎛ −=
2
2
1
1
d
d
Z
Z
K
K
S x
y
c
o
o
This equation is useful in developing direct integration techniques.
(b) If Q h l di h d h d Q d h
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(b) If Qo represents the normal discharge at a depth y o and Qc denotes the
critical discharge
at
the
same
depth
y ,
oo SK Q =
g Z Qc =and
Using these definitions, the GVF dynamic equation in (a) can be rewritten as
2
2
1
1
dd
⎟⎟ ⎞
⎜⎜⎝
⎛ −
⎟⎟
⎠
⎞⎜⎜
⎝
⎛ −
=
c
no
Q
Q
S x y
( ) A th f f th GVF d i ti i
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(c) Another form of the GVF dynamic equation is
This equation is called the differential‐energy equation of GVF to distinguish
it from
the
other
GVF
differential
equations.
This
energy
equation
is
very
useful in developing numerical techniques for the GVF profile computation.
f o SS x
E −=
d
d
Analysis of GVF Profile
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Analysis of GVF Profile
Among the importance are:
(a) determination of the effect of hydraulic structure to the flow;
(b) inundation due
to
dam
or
weir
construction;
and
(c) estimation of flood area.
This course only considers the following methods:
(a) Direct integration;
(b) Numerical integration;
and
(c) Direct step.
Calculation of GVF Profile
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Calculation of GVF Profile
Gradually‐varied
flow surface
y 1 y N+1
L
Δ x 1 Δ x 2 Δ x N
y 1+Δy 1 y 1+Δy 2
Changes in depth of flow can be calculated if:
(a) y 1 and y N+1 are known, or
(b) L is known
x
y
d
d
A. Direct Integration
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A. Direct Integration
( ) ( ) ( )[ ] ( ) ( )[ ]⎪⎭
⎪⎬⎫
⎪⎩
⎪⎨⎧
−⎟⎟
⎠
⎞⎜⎜
⎝
⎛ +−−−=− Jv F Jv F
M
J
y
y NuF NuF uu
S
y x x
M
c ,,,, 12o
1212
o
o12
Between two sections ( x 1, y 1) and ( x 2, y 2),
M, N = hydraulic exponents
F (u, N) = varied‐flow function
F (v , J) = same function as F (u, N)
oy y u = J
N
uv =( )1+−
=MNN J
where,
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Section M N
Rectangular 3 2 to 3.333
Trapezoidal 3 to
5 2
to
5.333
Triangular 5 5.333
⎟ ⎞⎜⎝ ⎛ −=
y T
T AT
Ay M
dd3
⎟ ⎞
⎜
⎝
⎛ −=
y
PRT
A
y N
d
d25
3
2
For trapezoidal channels,
⎟ ⎞
⎜⎝ ⎛ +
−⎟ ⎞
⎜⎝ ⎛ +
⎟ ⎠
⎞⎜⎝
⎛ +
=
B
y z
B
y z
B
y z
B
y z
M
21
2
1
213
⎥⎦
⎤⎢⎣
⎡ +⎟ ⎠ ⎞
⎜⎝ ⎛ +
+⎟ ⎠
⎞⎜⎝
⎛
−⎟ ⎠ ⎞
⎜⎝ ⎛ +
⎟ ⎠
⎞⎜⎝
⎛ +
=2
2
121
1
38
1
21
310
zB
y
z
B
y
B
y z
B
y z
N
3.0
4.05.06.0
y z
1
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2.5 3.0 3.5 4.0 4.5 5.0 5.50.02
M
0.03
0.05
0.1
0.04
0.2
0.3
0.06
0.08
0.40.50.6
0.81.0
2.0
o
andD
y
B
y
z =
2
BFC21103 Hydraulics
Tan et al. ([email protected])
z
=
0 ( r
e c t a n g u l a r )
z =
0 . 5
z =
1 . 5
z =
1
z = 4z = 3z = 2.5
Circular
Doy
B
3.0
4.05.06.0
y z
1z
= 0
( 5
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N
o
andD
y
B
y
BFC21103 Hydraulics
Tan et al. ([email protected])
2.0 2.5 3.0 3.5 4.0 4.5 5.00.02
0.03
0.05
0.1
0.04
0.2
0.3
0.06
0.08
0.40.50.6
0.81.0
2.0
5.5
Bz ( r
e
c t a n g u l a r )
Doy
C i r c u l ar
z = 0 . 5
z =
1
z = 1 . 5
z = 2.5z = 2
z = 4z = 3
N 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
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u
0.000.02
0.04
0.06
0.08
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.10
0.12
0.14
0.16
0.18
0.100
0.120
0.141
0.161
0.181
0.100
0.120
0.140
0.161
0.181
0.100
0.120
0.140
0.160
0.181
0.100
0.120
0.140
0.160
0.180
0.100
0.120
0.140
0.160
0.180
0.100
0.120
0.140
0.160
0.180
0.100
0.120
0.140
0.160
0.180
0.100
0.120
0.140
0.160
0.180
0.100
0.120
0.140
0.160
0.180
0.100
0.120
0.140
0.160
0.180
0.20
0.22
0.24
0.26
0.28
0.202
0.223
0.243
0.264
0.286
0.201
0.222
0.242
0.263
0.284
0.201
0.221
0.242
0.262
0.283
0.201
0.221
0.241
0.262
0.282
0.200
0.221
0.241
0.261
0.282
0.200
0.220
0.241
0.261
0.281
0.200
0.220
0.240
0.261
0.281
0.200
0.220
0.240
0.260
0.281
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.30
0.32
0.34
0.36
0.38
0.307
0.329
0.350
0.373
0.395
0.305
0.326
0.348
0.370
0.392
0.304
0.325
0.346
0.367
0.389
0.303
0.324
0.344
0.366
0.387
0.302
0.323
0.343
0.364
0.385
0.302
0.322
0.343
0.363
0.384
0.301
0.322
0.342
0.363
0.383
0.301
0.321
0.342
0.362
0.383
0.301
0.321
0.341
0.362
0.382
0.300
0.321
0.341
0.361
0.382BFC21103 Hydraulics Tan et al. ([email protected])
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
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BFC21103 Hydraulics
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u
0.400.42
0.44
0.46
0.48
0.4180.441
0.465
0.489
0.514
0.4140.437
0.460
0.483
0.507
0.4110.433
0.456
0.478
0.502
0.4080.430
0.452
0.475
0.497
0.4070.428
0.450
0.472
0.494
0.4050.426
0.448
0.470
0.492
0.4040.425
0.446
0.468
0.489
0.4030.424
0.445
0.466
0.488
0.4030.423
0.444
0.465
0.486
0.4020.423
0.443
0.464
0.485
0.50
0.52
0.54
0.56
0.58
0.539
0.565
0.592
0.619
0.647
0.531
0.556
0.582
0.608
0.635
0.525
0.550
0.574
0.600
0.626
0.521
0.544
0.568
0.593
0.618
0.517
0.540
0.563
0.587
0.612
0.514
0.536
0.559
0.583
0.607
0.511
0.534
0.556
0.579
0.603
0.509
0.531
0.554
0.576
0.599
0.508
0.529
0.551
0.574
0.596
0.506
0.528
0.550
0.572
0.594
0.60
0.61
0.62
0.63
0.64
0.676
0.691
0.707
0.722
0.738
0.663
0.677
0.692
0.707
0.722
0.653
0.666
0.680
0.694
0.709
0.644
0.657
0.671
0.684
0.698
0.637
0.650
0.663
0.676
0.690
0.631
0.644
0.657
0.669
0.683
0.627
0.639
0.651
0.664
0.677
0.623
0.635
0.647
0.659
0.672
0.620
0.631
0.643
0.655
0.667
0.617
0.628
0.640
0.652
0.664
0.65
0.66
0.67
0.68
0.69
0.754
0.771
0.787
0.805
0.822
0.737
0.753
0.769
0.785
0.802
0.724
0.739
0.754
0.769
0.785
0.712
0.727
0.742
0.757
0.772
0.703
0.717
0.731
0.746
0.761
0.696
0.709
0.723
0.737
0.751
0.689
0.703
0.716
0.729
0.743
0.684
0.697
0.710
0.723
0.737
0.680
0.692
0.705
0.718
0.731
0.676
0.688
0.701
0.713
0.726
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
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u
0.700.71
0.72
0.73
0.74
0.8410.859
0.878
0.898
0.918
0.8190.837
0.855
0.874
0.893
0.8020.819
0.836
0.853
0.871
0.7870.804
0.820
0.837
0.854
0.7760.791
0.807
0.823
0.840
0.7660.781
0.796
0.811
0.827
0.7570.772
0.786
0.802
0.817
0.7500.764
0.779
0.793
0.808
0.7440.758
0.772
0.786
0.800
0.7390.752
0.766
0.780
0.794
0.75
0.76
0.77
0.78
0.79
0.939
0.961
0.984
1.007
1.031
0.912
0.933
0.954
0.976
0.998
0.890
0.909
0.929
0.950
0.971
0.872
0.890
0.909
0.929
0.949
0.857
0.874
0.892
0.911
0.930
0.844
0.861
0.878
0.896
0.914
0.833
0.849
0.866
0.883
0.901
0.823
0.839
0.855
0.872
0.889
0.815
0.830
0.846
0.862
0.879
0.808
0.823
0.838
0.854
0.870
0.80
0.81
0.82
0.83
0.84
1.056
1.083
1.110
1.139
1.170
1.022
1.047
1.072
1.099
1.128
0.994
1.017
1.041
1.067
1.093
0.970
0.992
1.015
1.039
1.064
0.950
0.971
0.993
1.016
1.040
0.934
0.954
0.974
0.996
1.019
0.919
0.938
0.958
0.979
1.001
0.907
0.925
0.945
0.965
0.985
0.896
0.914
0.932
0.952
0.972
0.887
0.904
0.922
0.940
0.960
0.85
0.86
0.87
0.88
0.89
1.202
1.236
1.273
1.312
1.355
1.158
1.190
1.224
1.260
1.300
1.122
1.151
1.183
1.217
1.254
1.091
1.119
1.149
1.181
1.216
1.065
1.092
1.120
1.151
1.183
1.043
1.068
1.095
1.124
1.155
1.024
1.048
1.074
1.101
1.131
1.007
1.031
1.055
1.081
1.110
0.993
1.015
1.039
1.064
1.091
0.980
1.002
1.025
1.049
1.075
N
u 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
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BFC21103 Hydraulics
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u
0.900.91
0.92
0.93
0.94
1.4011.452
1.508
1.572
1.645
1.3431.390
1.442
1.500
1.568
1.2941.338
1.386
1.441
1.503
1.2531.294
1.340
1.391
1.449
1.2181.257
1.300
1.348
1.403
1.1891.225
1.266
1.311
1.363
1.1631.197
1.236
1.279
1.328
1.1401.173
1.210
1.251
1.297
1.1201.152
1.187
1.226
1.270
1.1031.133
1.166
1.204
1.246
0.950
0.960
0.970
0.975
0.980
1.730
1.834
1.968
2.052
2.155
1.647
1.743
1.865
1.943
2.040
1.577
1.666
1.780
1.851
1.936
1.518
1.601
1.707
1.773
1.855
1.467
1.545
1.644
1.707
1.783
1.423
1.497
1.590
1.649
1.720
1.385
1.454
1.543
1.598
1.666
1.352
1.417
1.501
1.553
1.617
1.322
1.385
1.464
1.514
1.575
1.296
1.355
1.431
1.479
1.536
0.985
0.990
0.995
0.999
1.000
2.294
2.477
2.792
3.523
∞
2.165
2.333
2.621
3.292
∞
2.056
2.212
2.478
3.097
∞
1.959
2.106
2.355
2.931
∞
1.880
2.017
2.250
2.788
∞
1.812
1.940
2.159
2.663
∞
1.752
1.873
2.079
2.554
∞
1.699
1.814
2.008
2.457
∞
1.652
1.761
1.945
2.370
∞
1.610
1.714
1.889
2.293
∞
1.001
1.005
1.010
1.015
1.020
3.317
2.587
2.273
2.090
1.961
2.931
2.272
1.984
1.817
1.698
2.640
2.021
1.756
1.602
1.493
2.399
1.818
1.572
1.428
1.327
2.184
1.649
1.419
1.286
1.191
2.008
1.506
1.291
1.166
1.078
1.856
1.384
1.182
1.065
0.982
1.725
1.279
1.089
0.978
0.900
1.610
1.188
1.007
0.902
0.828
1.508
1.107
0.936
0.836
0.766
N
u 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
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u
1.031.04
1.05
1.06
1.07
1.7791.651
1.552
1.472
1.405
1.5321.415
1.325
1.252
1.191
1.3401.232
1.149
1.082
1.026
1.1861.086
1.010
0.947
0.895
1.0600.967
0.896
0.838
0.790
0.9550.868
0.802
0.748
0.703
0.8660.785
0.723
0.672
0.630
0.7900.714
0.656
0.608
0.569
0.7250.653
0.598
0.553
0.516
0.6680.600
0.548
0.506
0.471
1.08
1.09
1.10
1.11
1.12
1.346
1.296
1.250
1.210
1.173
1.138
1.091
1.050
1.013
0.980
0.977
0.935
0.897
0.864
0.833
0.851
0.812
0.777
0.746
0.718
0.749
0.713
0.681
0.652
0.626
0.665
0.631
0.601
0.575
0.551
0.595
0.563
0.536
0.511
0.488
0.535
0.506
0.480
0.457
0.436
0.485
0.457
0.433
0.411
0.392
0.441
0.415
0.392
0.372
0.354
1.13
1.14
1.15
1.16
1.17
1.139
1.108
1.079
1.052
1.027
0.949
0.921
0.895
0.871
0.848
0.805
0.780
0.756
0.734
0.713
0.693
0.669
0.647
0.627
0.608
0.602
0.581
0.561
0.542
0.525
0.529
0.509
0.490
0.473
0.458
0.468
0.450
0.432
0.417
0.402
0.417
0.400
0.384
0.369
0.355
0.374
0.358
0.343
0.329
0.316
0.337
0.322
0.308
0.295
0.283
1.18
1.19
1.20
1.22
1.24
1.003
0.981
0.960
0.922
0.887
0.827
0.807
0.788
0.754
0.723
0.694
0.676
0.659
0.628
0.600
0.591
0.574
0.559
0.531
0.505
0.509
0.494
0.480
0.454
0.431
0.443
0.429
0.416
0.392
0.371
0.388
0.375
0.363
0.341
0.322
0.343
0.331
0.320
0.299
0.281
0.305
0.294
0.283
0.264
0.248
0.272
0.262
0.252
0.235
0.219
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
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u
1.261.28
1.30
1.32
1.34
0.8560.827
0.800
0.776
0.753
0.6940.669
0.645
0.623
0.603
0.5740.551
0.530
0.510
0.492
0.4820.461
0.442
0.424
0.408
0.4100.391
0.373
0.357
0.342
0.3510.334
0.318
0.304
0.290
0.3040.288
0.274
0.260
0.248
0.2650.250
0.237
0.225
0.214
0.2330.219
0.207
0.196
0.185
0.2050.193
0.181
0.171
0.162
1.36
1.38
1.40
1.42
1.44
0.731
0.711
0.692
0.675
0.658
0.584
0.566
0.549
0.534
0.519
0.475
0.459
0.444
0.431
0.418
0.393
0.378
0.365
0.353
0.341
0.329
0.316
0.304
0.293
0.282
0.278
0.266
0.256
0.246
0.236
0.237
0.226
0.217
0.208
0.199
0.204
0.194
0.185
0.177
0.169
0.176
0.167
0.159
0.152
0.145
0.153
0.145
0.138
0.131
0.125
1.46
1.48
1.50
1.55
1.60
0.642
0.627
0.613
0.580
0.551
0.505
0.492
0.479
0.451
0.425
0.405
0.394
0.383
0.358
0.335
0.330
0.320
0.310
0.288
0.269
0.273
0.263
0.255
0.235
0.218
0.227
0.219
0.211
0.194
0.179
0.191
0.184
0.177
0.161
0.148
0.162
0.156
0.149
0.135
0.123
0.139
0.133
0.127
0.114
0.103
0.119
0.113
0.108
0.097
0.087
1.65
1.70
1.75
1.80
1.85
0.525
0.501
0.480
0.460
0.442
0.403
0.382
0.364
0.347
0.332
0.316
0.298
0.282
0.267
0.254
0.251
0.236
0.222
0.209
0.198
0.203
0.189
0.177
0.166
0.156
0.165
0.153
0.143
0.133
0.125
0.136
0.125
0.116
0.108
0.100
0.113
0.103
0.095
0.088
0.082
0.094
0.086
0.079
0.072
0.067
0.079
0.072
0.065
0.060
0.055
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0
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1.901.95
2.00
2.10
2.20
0.4250.409
0.395
0.369
0.346
0.3170.304
0.292
0.273
0.251
0.2420.231
0.221
0.202
0.186
0.1880.178
0.169
0.154
0.141
0.1470.139
0.132
0.119
0.107
0.1170.110
0.104
0.092
0.083
0.0940.088
0.082
0.073
0.065
0.0760.070
0.066
0.058
0.051
0.0620.057
0.053
0.046
0.040
0.0500.046
0.043
0.037
0.032
2.3
2.4
2.5
2.6
2.7
0.326
0.308
0.292
0.277
0.264
0.235
0.220
0.207
0.195
0.184
0.173
0.160
0.150
0.140
0.131
0.129
0.119
0.110
0.102
0.095
0.098
0.089
0.082
0.076
0.070
0.075
0.068
0.062
0.057
0.052
0.058
0.052
0.047
0.043
0.039
0.045
0.040
0.036
0.033
0.029
0.035
0.031
0.028
0.025
0.022
0.028
0.024
0.022
0.019
0.017
2.8
2.9
3.0
3.5
4.0
0.252
0.241
0.230
0.190
0.161
0.175
0.166
0.158
0.126
0.104
0.124
0.117
0.110
0.085
0.069
0.089
0.083
0.078
0.059
0.046
0.065
0.060
0.056
0.041
0.031
0.048
0.044
0.041
0.029
0.022
0.036
0.033
0.030
0.021
0.015
0.027
0.024
0.022
0.015
0.010
0.020
0.018
0.017
0.011
0.007
0.015
0.014
0.012
0.008
0.005
4.5
5.0
6.0
7.0
8.0
0.139
0.122
0.098
0.081
0.069
0.088
0.076
0.058
0.047
0.040
0.057
0.048
0.036
0.028
0.022
0.037
0.031
0.022
0.017
0.013
0.025
0.020
0.014
0.010
0.008
0.017
0.013
0.009
0.006
0.005
0.011
0.009
0.006
0.004
0.003
0.008
0.006
0.004
0.002
0.002
0.005
0.004
0.002
0.002
0.001
0.004
0.003
0.002
0.001
0.001
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u 4.2 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8
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0.000.02
0.04
0.06
0.08
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.100.12
0.14
0.16
0.18
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.20
0.22
0.24
0.26
0.28
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.30
0.32
0.34
0.36
0.38
0.300
0.321
0.341
0.361
0.381
0.300
0.320
0.340
0.361
0.381
0.300
0.320
0.340
0.360
0.381
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
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u 4.2 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8
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0.700.71
0.72
0.73
0.74
0.7350.748
0.761
0.774
0.788
0.7270.740
0.752
0.765
0.779
0.7220.734
0.746
0.759
0.771
0.7170.729
0.741
0.753
0.766
0.7140.725
0.737
0.749
0.761
0.7110.723
0.734
0.746
0.757
0.7090.720
0.732
0.743
0.754
0.7080.719
0.730
0.741
0.752
0.7060.717
0.728
0.739
0.750
0.7050.716
0.727
0.737
0.748
0.750.76
0.77
0.78
0.79
0.8020.817
0.831
0.847
0.862
0.7920.806
0.820
0.834
0.849
0.7840.798
0.811
0.825
0.839
0.7780.791
0.804
0.817
0.831
0.7730.786
0.798
0.811
0.824
0.7690.781
0.794
0.806
0.819
0.7660.778
0.790
0.802
0.815
0.7630.775
0.787
0.799
0.811
0.7610.773
0.784
0.796
0.808
0.7600.771
0.782
0.794
0.805
0.80
0.81
0.82
0.83
0.84
0.878
0.895
0.912
0.931
0.949
0.865
0.881
0.897
0.914
0.932
0.854
0.869
0.885
0.901
0.918
0.845
0.860
0.875
0.890
0.906
0.838
0.852
0.867
0.881
0.897
0.832
0.846
0.860
0.874
0.889
0.828
0.841
0.854
0.868
0.883
0.824
0.837
0.850
0.863
0.877
0.820
0.833
0.846
0.859
0.873
0.818
0.830
0.842
0.855
0.869
0.85
0.86
0.87
0.88
0.89
0.969
0.990
1.012
1.035
1.060
0.950
0.970
0.990
1.012
1.035
0.935
0.954
0.973
0.994
1.015
0.923
0.940
0.959
0.978
0.999
0.913
0.930
0.947
0.966
0.986
0.904
0.921
0.937
0.955
0.974
0.897
0.913
0.929
0.946
0.964
0.892
0.907
0.922
0.939
0.956
0.887
0.901
0.916
0.932
0.949
0.882
0.896
0.911
0.927
0.943
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 4.2 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8
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0.900.91
0.92
0.93
0.94
1.0871.116
1.148
1.184
1.225
1.0601.088
1.117
1.151
1.188
1.0391.064
1.092
1.123
1.158
1.0211.045
1.072
1.101
1.134
1.0071.029
1.054
1.081
1.113
0.9941.016
1.040
1.066
1.095
0.9841.004
1.027
1.052
1.080
0.9750.995
1.016
1.040
1.067
0.9670.986
1.007
1.030
1.055
0.9600.979
0.999
1.021
1.045
0.9500.960
0.970
0.975
0.980
1.2721.329
1.402
1.447
1.502
1.2321.285
1.351
1.393
1.443
1.1991.248
1.310
1.348
1.395
1.1721.217
1.275
1.311
1.354
1.1491.191
1.245
1.279
1.319
1.1291.169
1.220
1.252
1.290
1.1121.150
1.198
1.228
1.264
1.0971.134
1.179
1.208
1.242
1.0851.119
1.163
1.190
1.222
1.0731.107
1.148
1.174
1.205
0.985
0.990
0.995
0.999
1.000
1.573
1.671
1.838
2.223
∞
1.508
1.598
1.751
2.102
∞
1.454
1.537
1.678
2.002
∞
1.409
1.487
1.617
1.917
∞
1.371
1.443
1.565
1.845
∞
1.338
1.406
1.520
1.780
∞
1.310
1.373
1.481
1.725
∞
1.285
1.345
1.446
1.678
∞
1.263
1.320
1.416
1.635
∞
1.244
1.298
1.389
1.596
∞
1.001
1.005
1.010
1.015
1.020
1.417
1.036
0.873
0.778
0.711
1.264
0.915
0.766
0.680
0.620
1.138
0.817
0.681
0.602
0.546
1.033
0.736
0.610
0.537
0.486
0.951
0.669
0.551
0.483
0.436
0.870
0.611
0.501
0.438
0.394
0.803
0.562
0.459
0.399
0.358
0.746
0.519
0.422
0.366
0.327
0.697
0.481
0.390
0.337
0.300
0.651
0.448
0.361
0.311
0.277
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 4.2 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8
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Tan et al. ([email protected])
1.031.04
1.05
1.06
1.07
0.6180.554
0.504
0.464
0.431
0.5350.477
0.432
0.396
0.366
0.4690.415
0.374
0.342
0.315
0.4150.365
0.328
0.298
0.273
0.3700.324
0.290
0.262
0.239
0.3320.290
0.258
0.232
0.211
0.3000.261
0.231
0.207
0.188
0.2730.236
0.208
0.186
0.168
0.2500.215
0.189
0.168
0.151
0.2290.196
0.172
0.152
0.136
1.081.09
1.10
1.11
1.12
0.4030.379
0.357
0.338
0.321
0.3410.319
0.299
0.282
0.267
0.2920.272
0.254
0.239
0.225
0.2520.234
0.218
0.204
0.192
0.2200.204
0.189
0.176
0.165
0.1940.179
0.165
0.154
0.143
0.1720.158
0.145
0.135
0.125
0.1530.140
0.129
0.119
0.110
0.1370.125
0.114
0.105
0.097
0.1230.112
0.102
0.094
0.086
1.13
1.14
1.15
1.16
1.17
0.305
0.291
0.278
0.266
0.254
0.253
0.240
0.229
0.218
0.208
0.212
0.201
0.191
0.181
0.173
0.181
0.170
0.161
0.153
0.145
0.155
0.146
0.137
0.130
0.123
0.134
0.126
0.118
0.111
0.105
0.117
0.109
0.102
0.096
0.090
0.102
0.095
0.089
0.083
0.078
0.090
0.084
0.078
0.072
0.068
0.080
0.074
0.068
0.064
0.059
1.18
1.19
1.20
1.22
1.24
0.244
0.235
0.226
0.209
0.195
0.199
0.191
0.183
0.168
0.156
0.165
0.157
0.150
0.138
0.127
0.138
0.131
0.125
0.114
0.104
0.116
0.110
0.105
0.095
0.086
0.099
0.093
0.089
0.080
0.072
0.085
0.080
0.076
0.067
0.061
0.073
0.069
0.065
0.057
0.051
0.063
0.059
0.056
0.049
0.044
0.055
0.052
0.048
0.042
0.037
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 4.2 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8
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1.261.28
1.30
1.32
1.34
0.1820.170
0.160
0.150
0.142
0.1450.135
0.126
0.118
0.110
0.1170.108
0.100
0.093
0.087
0.0950.088
0.081
0.075
0.069
0.0790.072
0.066
0.061
0.056
0.0650.059
0.054
0.050
0.045
0.0550.049
0.045
0.041
0.037
0.0460.041
0.037
0.034
0.031
0.0390.035
0.031
0.028
0.025
0.0330.030
0.026
0.024
0.021
1.361.38
1.40
1.42
1.44
0.1340.127
0.120
0.114
0.108
0.1030.097
0.092
0.087
0.082
0.0810.076
0.071
0.067
0.063
0.0640.060
0.056
0.052
0.049
0.0520.048
0.044
0.041
0.038
0.0420.038
0.035
0.033
0.030
0.0340.031
0.029
0.026
0.024
0.0280.025
0.023
0.021
0.019
0.0230.021
0.019
0.017
0.016
0.0190.017
0.015
0.014
0.013
1.46
1.48
1.50
1.55
1.60
0.103
0.098
0.093
0.083
0.074
0.077
0.073
0.069
0.061
0.054
0.059
0.056
0.053
0.046
0.040
0.046
0.043
0.040
0.035
0.030
0.036
0.033
0.031
0.026
0.023
0.028
0.026
0.024
0.020
0.017
0.022
0.021
0.019
0.016
0.013
0.018
0.016
0.015
0.012
0.010
0.014
0.013
0.012
0.010
0.008
0.011
0.010
0.010
0.008
0.006
1.65
1.70
1.75
1.80
1.85
0.067
0.060
0.054
0.049
0.045
0.048
0.043
0.038
0.035
0.031
0.035
0.031
0.027
0.024
0.022
0.026
0.023
0.020
0.017
0.015
0.019
0.017
0.014
0.013
0.011
0.014
0.012
0.010
0.009
0.008
0.011
0.009
0.008
0.007
0.006
0.008
0.007
0.006
0.005
0.004
0.006
0.005
0.004
0.004
0.003
0.005
0.004
0.003
0.003
0.002
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 4.2 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8
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1.901.95
2.00
2.10
2.20
0.0410.038
0.035
0.030
0.025
0.0280.026
0.023
0.020
0.016
0.0200.018
0.016
0.013
0.011
0.0140.012
0.011
0.009
0.007
0.0100.009
0.008
0.006
0.005
0.0070.006
0.005
0.004
0.003
0.0050.004
0.004
0.003
0.002
0.0040.003
0.003
0.002
0.001
0.0030.002
0.002
0.001
0.001
0.0020.002
0.001
0.001
0.001
2.32.4
2.5
2.6
2.7
0.0220.019
0.017
0.015
0.013
0.0140.012
0.010
0.009
0.008
0.0090.008
0.006
0.005
0.005
0.0060.005
0.004
0.003
0.003
0.0040.003
0.003
0.002
0.002
0.0030.002
0.002
0.001
0.001
0.0020.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.000
0.001
0.001
0.000
0.000
0.000
0.0010.000
0.000
0.000
0.000
2.8
2.9
3.0
3.5
4.0
0.012
0.010
0.009
0.006
0.004
0.007
0.006
0.005
0.003
0.002
0.004
0.004
0.003
0.002
0.001
0.002
0.002
0.002
0.001
0.000
0.001
0.001
0.001
0.001
0.000
0.001
0.001
0.001
0.000
0.000
0.001
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
4.5
5.0
6.0
7.0
8.0
0.003
0.002
0.001
0.001
0.000
0.001
0.001
0.000
0.000
0.000
0.001
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 4.2 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8
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9.010.0
20.0
0.0000.000
0.000
0.0000.000
0.000
0.0000.000
0.000
0.0000.000
0.000
0.0000.000
0.000
0.0000.000
0.000
0.0000.000
0.000
0.0000.000
0.000
0.0000.000
0.000
0.0000.000
0.000
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 8.2 8.6 9.0 9.4 9.8
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0.000.02
0.04
0.06
0.08
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.0000.020
0.040
0.060
0.080
0.100.12
0.14
0.16
0.18
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.1000.120
0.140
0.160
0.180
0.20
0.22
0.24
0.26
0.28
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.200
0.220
0.240
0.260
0.280
0.30
0.32
0.34
0.36
0.38
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
0.300
0.320
0.340
0.360
0.380
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 8.2 8.6 9.0 9.4 9.8
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BFC21103 Hydraulics Tan et al. ([email protected])
0.400.42
0.44
0.46
0.48
0.4000.420
0.440
0.460
0.480
0.4000.420
0.440
0.460
0.480
0.4000.420
0.440
0.460
0.480
0.4000.420
0.440
0.460
0.480
0.4000.420
0.440
0.460
0.480
0.500.52
0.54
0.56
0.58
0.5000.520
0.540
0.561
0.581
0.5000.520
0.540
0.560
0.581
0.5000.520
0.540
0.560
0.580
0.5000.520
0.540
0.560
0.580
0.5000.520
0.540
0.560
0.580
0.60
0.61
0.62
0.63
0.64
0.601
0.611
0.621
0.632
0.642
0.601
0.611
0.621
0.631
0.641
0.601
0.611
0.621
0.631
0.641
0.600
0.611
0.621
0.631
0.641
0.600
0.610
0.621
0.631
0.641
0.65
0.66
0.67
0.68
0.69
0.652
0.662
0.673
0.683
0.694
0.652
0.662
0.672
0.683
0.693
0.651
0.662
0.672
0.682
0.692
0.651
0.661
0.672
0.682
0.692
0.651
0.661
0.671
0.681
0.692
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 8.2 8.6 9.0 9.4 9.8
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0.700.71
0.72
0.73
0.74
0.7040.715
0.726
0.736
0.747
0.7040.714
0.725
0.735
0.746
0.7030.713
0.724
0.734
0.745
0.7020.713
0.723
0.734
0.744
0.7020.712
0.723
0.733
0.744
0.750.76
0.77
0.78
0.79
0.7580.769
0.780
0.792
0.804
0.7570.768
0.779
0.790
0.802
0.7560.767
0.778
0.789
0.800
0.7550.766
0.777
0.788
0.799
0.7540.765
0.776
0.787
0.798
0.80
0.81
0.82
0.83
0.84
0.815
0.827
0.839
0.852
0.865
0.813
0.825
0.837
0.849
0.862
0.811
0.823
0.835
0.847
0.860
0.810
0.822
0.833
0.845
0.858
0.809
0.820
0.831
0.844
0.856
0.85
0.86
0.87
0.88
0.89
0.878
0.892
0.907
0.921
0.937
0.875
0.889
0.903
0.918
0.933
0.873
0.886
0.900
0.914
0.929
0.870
0.883
0.897
0.911
0.925
0.868
0.881
0.894
0.908
0.922
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Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 8.2 8.6 9.0 9.4 9.8
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1.031.04
1.05
1.06
1.07
0.2120.173
0.158
0.140
0.123
0.1950.165
0.143
0.127
0.112
0.1810.152
0.132
0.116
0.102
0.1700.143
0.124
0.106
0.094
0.1590.134
0.115
0.098
0.086
1.081.09
1.10
1.11
1.12
0.1110.101
0.092
0.084
0.077
0.1010.091
0.083
0.075
0.069
0.0920.082
0.074
0.067
0.062
0.0840.075
0.067
0.060
0.055
0.0770.069
0.062
0.055
0.050
1.13
1.14
1.15
1.16
1.17
0.071
0.065
0.061
0.056
0.052
0.063
0.058
0.054
0.050
0.046
0.056
0.052
0.048
0.045
0.041
0.050
0.046
0.043
0.040
0.036
0.045
0.041
0.038
0.035
0.032
1.18
1.19
1.20
1.22
1.24
0.048
0.045
0.043
0.037
0.032
0.042
0.039
0.037
0.032
0.028
0.037
0.034
0.032
0.028
0.024
0.033
0.030
0.028
0.024
0.021
0.029
0.027
0.025
0.021
0.018
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 8.2 8.6 9.0 9.4 9.8
1 26 0 028 0 024 0 021 0 018 0 016
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1.261.28
1.30
1.32
1.34
0.0280.025
0.022
0.020
0.018
0.0240.021
0.019
0.017
0.015
0.0210.018
0.016
0.014
0.012
0.0180.016
0.014
0.012
0.010
0.0160.014
0.012
0.010
0.009
1.361.38
1.40
1.42
1.44
0.0160.014
0.013
0.011
0.010
0.0130.012
0.011
0.009
0.008
0.0110.010
0.009
0.008
0.007
0.0090.008
0.007
0.006
0.006
0.0080.007
0.006
0.005
0.005
1.46
1.48
1.50
1.55
1.60
0.009
0.009
0.008
0.006
0.005
0.008
0.007
0.006
0.005
0.004
0.006
0.005
0.005
0.004
0.003
0.005
0.004
0.004
0.003
0.002
0.004
0.004
0.003
0.003
0.002
1.65
1.70
1.75
1.80
1.85
0.004
0.003
0.002
0.002
0.002
0.003
0.002
0.002
0.001
0.001
0.002
0.002
0.002
0.001
0.001
0.002
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
0.001
Varied‐flow function for positive slopes F(u, N) (Chow, 1959)
N
u 8.2 8.6 9.0 9.4 9.8
1 90 0 001 0 001 0 001 0 001 0 000
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1.901.95
2.00
2.10
2.20
0.0010.001
0.001
0.001
0.000
0.0010.001
0.001
0.000
0.000
0.0010.001
0.000
0.000
0.000
0.0010.000
0.000
0.000
0.000
0.0000.000
0.000
0.000
0.000
2.32.4
2.5
2.6
2.7
0.0000.000
0.000
0.000
0.000
0.0000.000
0.000
0.000
0.000
0.0000.000
0.000
0.000
0.000
0.0000.000
0.000
0.000
0.000
0.0000.000
0.000
0.000
0.000
2.8
3.0
4.0
5.0
6.0
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
7.0
8.0
9.0
10.0
20.0
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
Steps in direct integration method:
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1. Calculate y o and y c
2. Determine N and M
3. Calculate J
4. Calculate u and v
5. Find F (u, N) and F (v , J)
6. Calculate length of the reach
Activity 4.7
A very wide river with Manning roughness n = 0.035 has uniform depth of
3 0 m and longitudinal slope of 0 0005 Based on direct integration method
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3.0 m
and
longitudinal
slope
of
0.0005.
Based
on
direct
integration
method,
estimate the length of nonuniform flow produced by a weir that caused the
water surface to increase as much as 1.5 m upstream of weir.
4.5 my o = 3 m
So = 0.0005; n = 0.035
Step 1. Calculate y o and y c
y o = 3.0 m
12
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2
1
o3
2
o
1SRy
nq =
(For very
wide
channel,
R ≈ y )
2
1
o
3
5
o
1
Sy nq =
2
1
3
5
0005.03035.0
1××=q
/sm987.3 2=q
3
123
12
81.9
987.3⎟⎟
⎞⎜⎜
⎝
⎛ =⎟⎟
⎞⎜⎜
⎝
⎛ =
g
qy
c
m175.1=cy
profileMm175.1m3m4.5tom3 1o →=>=>= cy y y
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Step 5. Find F (u1, N), F (u2, N), F (v 1, J), and F (v 2, J)
( ) ( ) 907.1333.3,001.1,1 == F NuF
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( ) [ ] [ ]⎭⎬⎫
⎩⎨⎧ −×⎟
⎠ ⎞⎜
⎝ ⎛ +−−−= 786.23342.0
3
5.2
3
175.1907.11884.0001.15.10005.0
3 3L
( ) ( ) 1884.0333.3,5.1,2 == F NuF
( ) ( ) 786.25.2,001.1,1 == F Jv F
( ) ( ) 3342.05.2,717.1,2 == F Jv F
Step
6.
Calculate
length
of
channel
reach
( ) ( ) ( )[ ] ( ) ( )[ ]⎪⎭
⎪⎬⎫
⎪⎩
⎪⎨⎧
−⎟⎟ ⎠
⎞⎜⎜⎝
⎛ +−−−=− Jv F Jv F
M
J
y
y NuF NuF uu
S
y x x
M
c ,,,, 12o
1212
o
o12
m 05.12569=L
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4.5 my o = 3 m
So = 0.0005;
n =
0.035
y = 3.003 m
L = 12569.05 m
B. Numerical IntegrationSection Equations used
All sections 2K ⎤⎡ ⎞⎛ ⎤⎡2TQ
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All sections
Rectangular
Very wide channel
(Chezy)
3
2
oo
1
1
d
d
gA
T Q
K
K S
x
y ave
−
⎥⎥⎦
⎤
⎢⎢⎣
⎡⎟⎟ ⎠
⎞⎜⎜⎝
⎛ −
=
⎥
⎥⎥⎥⎥
⎦
⎤
⎢
⎢⎢⎢⎢
⎣
⎡
⎟⎟
⎠
⎞
⎜⎜⎝
⎛ −
−
= 2
o
3
o1
1d
d
aveK
K
gA
T Q
S
y x
3
2
oo
1
1
d
d