CHAPTER 5 : NON UNIFORM FLOW IN OPEN CHANNEL · CHAPTER 5 : NON UNIFORM FLOW IN OPEN CHANNEL OPEN...
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CHAPTER 5 : NON UNIFORM FLOW IN OPEN CHANNEL OPEN CHANNEL : A CHANNEL WHERE THE WATER FLOWS WITH MAINLY BY GRAVITY FORCE AND THERE HAS A FREE SURFACE AND ATMOSPHERE PRESSURE ON THE WATER. EXAMPLE
Transcript of CHAPTER 5 : NON UNIFORM FLOW IN OPEN CHANNEL · CHAPTER 5 : NON UNIFORM FLOW IN OPEN CHANNEL OPEN...
CHAPTER 5 : NON UNIFORM
FLOW IN OPEN CHANNEL
OPEN CHANNEL : A CHANNEL
WHERE THE WATER FLOWS WITH
MAINLY BY GRAVITY FORCE AND
THERE HAS A FREE SURFACE
AND ATMOSPHERE PRESSURE ON
THE WATER.
EXAMPLE
CHAPTER 5
1.Uniform flow
2.Non uniform flow
Steady Uniform Flow
UnSteady Uniform Flow
Steady Non
Uniform Flow
UnSteady Non
Uniform Flow
Rapidly Varied
Flow
Gradually Varied
Flow
TYPE OF FLOW :
CHAPTER 5
Uniform flow
- Depth, discharge & velocity
constant along the length of the
channel
y1 = y2
v1 = v2
v1 v2y1
y2
Q
CHAPTER 5
Non uniform flow
- Depth, discharge & velocity is
different along the length of the
channel
y1 = y2
v1 = v2
v1 v2y1
y2
Q
CHAPTER 5
Steady uniform flow -
- Depth, discharge & velocity is
constant along the length of the
channel and not change with time
Constant
depth
Constant
velocity
CHAPTER 5
UnSteady uniform flow
- Depth, discharge & velocity is
constant along the length of the
river but changed with time
CHAPTER 5
Steady non-uniform flow
- Depth, discharge & velocity is not
constant along the length of the
river and not changed with time
v1 v2y1
y2
Q
CHAPTER 5
UnSteady non-uniform flow -
- Depth, discharge & velocity is not
constant along the length of the
river and changed with time
v1 v2y1
y2
Q
CHAPTER 5
Gradually Varied flow
- Depth, discharge & velocity is
changed slowly along the length of
the river
- Example : Backwater in Sluice gate
v1 v2y1
y2
Q
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Rapidly Varied flow
- Depth, discharge & velocity is
changed rapidly along the length of
the river
- Example: Hydraulic jump
v1 v2y1
y2
Q
CHAPTER 5
CHAPTER 5
Specific Energy, E
Total of depth and kinetic energy of
the flow.
E = y + v2
2g
CHAPTER 5
Specific Energy, E
Alternath depth
CHAPTER 5
Specific Energy, E
Example 1:
A trapezoidal channel has dimension
of bottom width 6m and side slope
1:1 flows water at rate 8 m3/s.
Calculate specific energy for the
water if the depth of water is 2m.
2m1
1
CHAPTER 5
Discharge per unit width, q
q = Q
b
Froude Number, Fr
-Used to determine characteristic of flow
* Only for square &
prismatic channel
Fr = v
√(gy)
Fr < 1: subcritical (tranquil) flow
Fr = 1: critical flow
Fr > 1: supercritical (rapid) flow
CHAPTER 5
Subcritical flow
- Deep, calm
Critical depth, yc
Supercritical flow
- Shallow, fast
Critical flow
- Disturbance, small gravities wave
yc
= q2
g
1
3
CHAPTER 5
Minimum energy, Emin
Critical velocity, vc
Emin
= 3
2
yc
vc
= √(gyc)
CHAPTER 5
Example 2:
Water flows in square channel
which the width of the channel is 6m
and the depth of the water is 3m. If
the flowrate is 30 m3/s, calculate:
a. Froude number
b. Type of flow
c. Critical depth
CHAPTER 5
HYDRAULIC JUMP
- THE SUDDEN INCREASE IN
DEPTH OF FLOW IN SHORT
DISTANCE
- THE TRANSITIONAL FLOW FROM
SUPERCRITICAL TO SUBCRITICAL
CHAPTER 5
HYDRAULIC JUMP IN LABORATORY
CHAPTER 5
WHERE HYDRAULIC
JUMP OCCUR?
1. At the bottom of hydraulic
structure which supercritical flow
through into stilling basin.
2. At downstream of flum which the
supercritical flow transit to
subcritical flow.
3. In the trashrack channel
CHAPTER 5
TYPES OF HYDRAULIC JUMP
1. Undular Jump Fr1
1.0 – 1.7
2. Weak Jump Fr1
1.7 – 2.5
3. Oscillating Jump Fr1
2.5 – 4.5
4. Steady Jump Fr1
4.5 – 9.0
5. Strong Jump Fr1
> 9.0
CHAPTER 5
THE APPLICATION OF
HYDRAULIC JUMP
1. As Energy Disperser
2. For Chemical Diffusion
3. For Aeration
4. To increase Flow Level
