to study the characteristics of the hydraulic jump developed in lab flume

7/31/2019 To study the characteristics of the hydraulic jump developed in lab flume.

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Hydraulics Engineering I Lab Manual

EXPERIMENT NO 4

To study the characteristics of the hydraulic jumpdeveloped in lab flume.

OBJECTIVE

1.To physically achieve the hydraulic jump in lab flume.2.To measure the physical dimensions of hydraulic jump.3.To calculate the energy losses through hydraulic jump.4.To plot the water surface profile of the hydraulic jump. For

various discharges.

APPARATUS

1. S6 tilting or lab flume with manometer flow arrangementand slope adjusting scale.

2. Hook gauge

RELATED THEORY

1. HYDRAULIC JUMPThe rise of water level which takes place due to

transformation of super critical flow to the sub critical flow istermed as hydraulic jump.

Afzal Waseem 2007-Civil-87

d1

2

2

1

1

d2

Dam

yc

1


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d1 < yc Super critical flowd1 < yc Sub critical flow

2.

2. EXPRESSION FOR THE DEPTH OF HYDRAULICJUMP

Depth = d2-d1

If d1 is known

3. EXPRESSION FOR LOSS OF ENERGY DUE TOHYDRAULIC JUMP

Afzal Waseem 2007-Civil-87 2


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hL = E1 E2On simplifying

4. LENGTH OF HYDRAULIC JUMPDistance between section where one section is taken justbefore the hydraulic jump and second section is taken afterthe hydraulic jump

Length = 5-7 times of depth

5. LOCATION OF HYDRAULIC JUMPLocation of jump depends upon d2 and y2y2 = Normal depth of flow on downstream side.

Case No. 1 d2 < y2


d1

2

2

1

1

d2

Damy

c

hLW.L

d2

2

2

y2U/S D/S

Dam

3

E.L


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Strength of jump is the amount of energy dissipated due tostructure.

Jump is submerged in water so it is a weak jump.

Case No. 2 d2 = y2

Strength of jump is the amount of energy dissipated due tostructure.

Energy dissipated in this jump is more than in Case No. 1 soit has greater strength.

Case No. 3 d2 > y2


d2

2

2

y2U/S D/S

Dam

d2

2

2

y2U/S D/S

Dam

Floor

4


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Depth of floor is less so it will damage the floor.So Ideal Case will be Case No. 2 as structure is

i. Safeii. Sufficient energy dissipated

If Case No. 2 does not fit accordingly to the conditions then Case

No 1 will be use as it has less energy dissipation but it is safe butCase No. 3 will never be adopted as it is unsafe and by adoptingthis Case will resulting defoliation of the floor.

TYPES OF HYDRAULIC JUMPSection (1) will be controlling sectionFraud No at Section (1) F1

1. F1 < 1 Sub -Critical flow2. F1 = 1 Critical flow (No hydraulic jump)

3. F1 = 1 1.7 Undular Jump (Supercritical Flow)4. F1 = 1.7 2.5 Weak Jump (Supercritical Flow)5. F1 = 2.5 4.5 Oscillating Jump (Supercritical Flow)6. F1 = 4.5 9.0 Steady Jump (Supercritical Flow)7. F1 > 9.0 Strong Jump (Supercritical Flow)

PRACTICAL APPLICATIONS OF HYDRAULIC JUMP

1. To dissipate the energy of water flowing over thehydraulic structure and thus prevent scouring on the

downstream side.2. To recover the head or raise the water level on

downstream side of the hydraulic structure and thus tomaintain high water level in the channel for irrigation orother water distribution purposes.

3. To increase the weight on apron and thus reduce theuplift pressure under the structure by raising the waterdepth on apron.Apron: A layer of flexible material


U/S

D/S

Dam

Floor

ApronDrain water causinguplift pressure


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4. To mix the chemicals for water purification e.t.c

PROCEDURE

1. Fix one particular value of slope.2. Change the discharge every new reading.3. Measure the depth of flow at various locations.

4. Measure the horizontal distance at each section.5. Repeat the same procedure for various discharges.6. Plot the data in the form of Tables and Graphs.


to study the characteristics of the hydraulic jump developed in lab flume

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