The document contains 30 multiple choice questions about harbor and shore protection. Some key topics covered include types of sea walls, breakwaters, docks, and littoral drift. Questions test understanding of concepts like minimum basin diameters, lock gate design, and the impact of waves on coastal structures. The document is a quiz intended to assess knowledge of harbor and shore protection engineering topics.

1. 30 QUESTIONS IN HARBOR AND
SHORE PROTECTION
‫أ‬
‫اطئ‬‫و‬‫ش‬‫ل‬‫ا‬‫وحامية‬ ‫اين‬‫و‬‫مل‬‫ا‬ ‫عامل‬
By: Dr. Ezzat El-Sayed G. SALEH

6. The difference in height between highest water and lowest water is called:
a) Mean range,
b) Maximum range, 
c) Maximum rise,
d) Mean rise.
The minimum diameter of turning basin, where ships turn by going ahead and without tug
assistance should be:
a) L,
b) 1.5 L,
c) 2 L,
d) 4 L. 
Where “L” is the length of the largest ship to use the port.
Dead weight tonnage of a ship:
i. Varies with latitude and season
ii. Is more than displacement tonnage
iii. Is the difference between displacement load and displacement light of these
statements
a) i) and ii) are correct,
b) ii) and iii) are correct,
c) i) and iii) are correct, 
d) Only iii) is correct.

7. By increasing the rise of lock gates,
i. The length of the gate will increase
ii. Transverse stress due to water pressure on the gate will increase
iii. Compressive force on the gate will increase of these statements
a) i) and ii) are correct, 
b) i) and iii) are correct,
c) Only ii) is correct,
d) Only iii) is correct.
Which of the following structures protects the shore by trapping of littoral drift?
a) groynes, 
b) sea walls,
c) revetments,
d) moles.

9. Which of the following structures are constructed parallel to shore line to develop a
demarcating line between land area and water area?
a) sea walls, bulk heads and groynes,
b) sea walls, bulk heads and revetments, 
c) sea walls, revetments, and groynes,
d) bulk heads , revetments, and groynes.
Which of the following type of sea walls results in greatest protection of shore structures?
a) vertical sea wall
b) sea wall with batter
c) Steeped sea wall,
d) sea wall with concave face. 
What are the materials used in building a gravity dam?

10. A river training work is generally required when the river is:
a) aggrading type
b) degrading type
c) meandering type 
d) Both (a) and (b).
A river bend characterized by silting:
a) scouring on concave side
b) silting on convex side
c) scouring on convex side and on concave side
d) scouring on concave side and silting convex side. 

11. The dock wall is designed as a gravity retaining wall and is tested for
1. maximum water pressure from the dock without any back fill
2. back fill pressure when the dock is empty
3. the load charge transmitted to the dock by the movement of loaded
vehicles or trains on the way
4. all of the above. 
Due to the impact of water wave on a sea shore structure
1. weakens the foundation
2. all of the above. 
3. vibrations are subjected
4. internal pressure is developed

12. Pick up the correct statement from the following:
1. The brick masonry retaining wall which is used for loading and unloading of
cargo is called guay wall
2. The breakwater which can be used as a platform for loading and unloading
of cargo is called a mole
3. Three types of break waters are generally provided in harbors
4. All of the above. 

13. A harbor is a place where
1. ships get shelter and protection against destructive forces due to sea
waves
2. all of the above. 
3. facilities are provided for receiving cargo and passengers
4. port buildings are constructed for commercial purposes
The shape of docks and basins is generally kept
1. diamond shape gays
2. rectangular ways
3. inclined gays
4. all of these. 

14. Pick up the incorrect statement from the following:
1. A falling hydraulic gradient occurs in the direction of the wave 
2. The wave while receding carries finer particles out to deep water.
3. As a wave of sea water approaches the coast line, it is generally
accompanied by a drift of water in the direction of wave advance
4. The on-shore wind helps to produce wave action as well as rise of M.S.L
The important component of a sea port is
1. terminal buildings
2. the docks.
3. the harbor
4. all of these 

15. On the sea shore structures, the water wave impact causes
1. compressive force due to collapse of the wave
2. shear force due to deflected vertical force
3. all of the above. 
4. suction force due to water returning after striking
A roadstead (
‫طبيعي‬ ‫مرسي‬
) :
1. is the end of the road at the harbor
2. is a protected area of water where boats can move safely . 
3. may be protected by break water walls
4. none of these.
The width of the entrances of the harbors is restricted to
1. 100 m
2. 120 m
3. 140 m
4. 180 m 

16. A dock is:
1. provided with a dock gate
2. all the above. 
3. an artificial basin for vessels where the variation of water in the shore
does not affect the level of water
4. provided with an arrangement to pump out water when required
According to the recommendations of International Navigational Congress
in 1912, the ratio of length to width at the entrance for passenger vessels
is :
1. 7.25 to 1
2. 8.11 to 1
3. 7.80 to 1
4. 8.44 to 1 

17. Pick up the correct statement from the following:
1. An artificial barrier (
‫حاحز‬
) which makes the enclosed area safe for
anchorage of ships, is known as break water
2. The break water whose inside is used as a platform for loading and
unloading is called a mole
3. The length of the quay wall is governed by the length of the largest vessel
likely to be berthed
4. All the above. 
Littoral drift (
‫الساحلي‬ ‫اإلنحراف‬
) is:
1. the raised line of sand, parallel to the sea coast
2. the slow movement of surface water at sea caused by the wind
3. a current parallel to the shore, caused due to tangential component of the
wind 
4. a current perpendicular to the shore line caused due to wind.
‫الساحلية‬ ‫النجراف‬

18. A low wall built out into the sea more or less perpendicular to the coast line, to
resist the travel of sand and shingle along a beach, is called
1. Groins 
2. Break wall
3. Break water
4. Shore wall.
The beach is built:
1. with largest material locally not available to the waves 
2. with fine material locally available to the waves
3. with finest material locally available to the waves.
4. with large material locally available to the waves

19. The shore line survey includes :
1. depicting the prominent details on shore line
2. depicting the high water line
3. depicting the low water line
4. all the above. 
Pick up the correct statement from the following:
1. The direction of a river opening to the sea determines the direction of no
littoral drift
2. Harbor in the path of littoral drift is not constructed to avoid a build up of
sand on one side and erosion on the other
3. all of the above. 
4. The direction of the littoral drift depends upon the direction of the wave
with respect to the coastline

20. Groynes are generally built:
1. Inclined up stream up to 30°
2. Inclined down stream up to 30°
3. Perpendicular to the bank
4. All 
A river training work is generally required when the river is
1. Meandering
2. Aggrading
3. All 
4. degrading

21. A fall in a canal bed is generally provided, if
1. None of these.
2. Ground slope exceeds the designed bed slope 
3. Ground slope is practically the same as the designed bed slope
4. Designed bed slope exceeds the ground slope
A hydraulic structure is designed to withstand
1. Seepage forces
2. Hydraulic pressure
3. All 
4. Hydraulic jump
Cross regulators in main canals are provided to:
1. Regulate water supply in the distributaries
2. Overflow excessive flow water
3. Increase water head upstream when a main canal is running with low
supplies 
4. none of these.

22. The ratio of the head recovered to the in put head, is known as
1. Efficiency 
2. Sensitivity
3. Modular limit.
4. Flexibility
If the total head of the nozzle of a pipe is 37.5 m and discharge is 1 cumec, the
power generated is
1. 550 H.P.
2. 400 H.P.
3. 450 H.P.
4. 500 H.P. 

23. A piezometer opening in pipes measures
1. velocity head
2. total pressure
3. static pressure
4. negative static pressure. 
When a body is totally or partially immersed in a fluid, it is buoyed up by a
force equal to
1. difference of weights of the fluid displaced and that of the body
2. weight of the body
3. weight of the fluid displaced by the body 
4. weight of the body and fluid displaced by the body
Reynolds number is the ratio of initial force and
1. elasticity
2. Viscosity 
3. gravitational force
4. surface tension.

24. The total pressure force on a plane area is equal to the area multiplied by the
intensity of pressure at its centroid, if
1. area is vertical
2. all the above. 
3. area is horizontal
4. area is inclined
If the volume of a liquid weighing 3000 kg is 4 cubic metres, 0.75 is its
1. specific weight
2. specific gravity . 
3. specific mass
4. none of these.
The thickness of a sharp crested weir is kept less than
1. one-fourth of the height of water on the sill
2. two-third of the height of water on the sill
3. one-half of the height of water on the sill 
4. one-third of the height of water on the sill

25. A short tube mouthpiece will not run full at its outlet if the head under which
the orifice works, is
1. equal of 12.2 m of water
2. more than 12.2 m of the water 
3. less than 12.2 m of the water
4. none of these
The horizontal component of the force on a curved surface is equal to
1. force on a vertical projection of the curved surface
2. weight of liquid vertically below the curved surface
3. product of pressure at its centroid and the area
4. weight of liquid retained by the curved area. 
The ratio of maximum velocity to average velocity of viscous fluid through a
circular pipe is
1. 0.75
2. 1.25
3. 0.5
4. 2 

26. The momentum correction factor (β) for the viscous flow through a circular pipe
is
1. 1.33 
2. 1.25
3. 1.50
4. 2
The maximum vacuum created at the summit of a syphon is
1. 7.4 m of water 
2. none
3. 5.5 m of water
4. 2.7 m of water
An independent mass of a fluid does not posses
1. kinetic energy
2. elevation energy
3. pressure energy 
4. none of these.

27. A syphon is used to:
1. Connect water reservoirs at different levels intervened by a hill 
2. Supply water to a town from higher level to lower level
3. Fill up a tank with water at higher level from a lower level
4. None of these.
An ideal flow of a liquid obeys
1. Newton's second law of motion
2. Newton's law of viscosity
1. 3. Continuity equation 
4. dynamic viscosity law,
The shear stress distribution in viscous fluid through a circular pipe is :
1. maximum at the inside of surface
2. maximum at the center
3. none of these.
4. same throughout the section 

28. The phenomenon occurring in an open channel when a rapidly flowing stream
abruptly changes to a slowly flowing stream causing a distinct rise of liquid
surface, is
1. water hammer
2. none of these.
3. critical discharge
4. hydraulic jump 
A Pitot tube is used to measure
1. velocity of flow  “Mainly”
2. pressure
3. none of these.
4. difference in pressure may be “Secondary” 
Flow in pipes is laminar if Reynolds number is
1. between 2100 and 3000
2. more than 3000
3. none of these.
4. less than 2100pressure 

29. The radius of gyration of the water line of a floating ship is 4 m and its
metacentric height is 72.5 cm. The period of oscillation of the ship, is
1. 3π 
2. 2π
3. 4π
4. π
Euler’s equation for the motion of liquids assumes that
1. fluid is homogeneous and incompressible 
2. fluid is viscous
3. velocity of flow is non-uniform over the section
4. flow is unsteady along the stream line.
Liquids
1. cannot be compressed
2. do not occupy definite shape 
3. none of these.
4. are not affected by change in pressure and temperature

30. The ratio of the inertia and gravitational force acting in any flow, ignoring
other forces, is called
1. Euler number
2. Froude number 
3. Weber number.
4. Reynolds number
For the most economical trapezoidal open channel,
1. the hydraulic mean depth must be equal to half the depth of flow
2. half of the top width must be equal to one of the sloping sides
3. the semicircle drawn with top width as diameter must touch the three sides
of the channel
4. All 
Differential manometers are used to measure:
1. atmospheric pressure
2. difference in pressure at two points 
3. pressure in water channels, pipes, etc.
4. very low pressure.

31. Gauge pressure is
1. atmospheric pressure - absolute pressure
2. absolute pressure + atmospheric pressure
3. none of these.
4. absolute pressure - atmospheric pressure 
The height of water level in a tank above the center of a circular hole 2.5 cm in
diameter is 50 m. The velocity of water flowing through the hole, is
1. 31.3 m/sec 
2. 31.2 m/sec
3. 31.4 m/sec.
4. 31.1 m/sec
The continuity equation
1. expresses the relationship between work and energy
2. relates mass rate of flow along a stream line 
3. requires that Newton's second law of motion be satisfied at every point in
fluid.
4. relates the momentum per unit volume between two points on a stream
line

32. In flow, the liquid particles may possess
1. pressure energy
2. kinetic energy
3. all the above. 
4. potential energy
Total head of a liquid particle in motion is the sum of
1. potential head and pressure head
2. kinetic head and pressure head
3. potential head and kinetic head
4. potential head, kinetic head and pressure head. 
The ratio of the percentage error in the discharge and percentage error in the
measurement of head over a triangular notch, is
1. 2/3
2. 5/2 
3. 2/5
4. 3/2

33. If jet of water coming out from a nozzle with a velocity 9.81 m/s, the angle of
elevation being 30°, the time to reach the highest point is
1. 1.5 s.
2. 0.25 s
3. 1.0 s
4. 0.50 s 
The velocity distribution of viscous fluid through a circular/pipe is :
1. Parabolic 
2. hyperbolic
3. circular
4. elliptical
In pipe lines, a surge tank is provided
1. to remove the frictional loss in pipe.
2. to relieve the pressure due to water hammer 
3. to provide additional water head
4. to overflow the pipe line when suddenly closed

34. Due to decrease of diameter of the droplet, inside pressure intensity
1. remains unaffected
2. Increases 
3. decreases
4. None of these.
Barometers are used to measure
1. difference in pressure at two points
2. very low pressure
3. pressure in water channels, pipes etc.
4. atmospheric pressure 
From a nozzle exposed to atmosphere, the liquid jet traverses
1. a straight line
2. a parabolic path. 
3. a circular path
4. an elliptical path

35. An error of 1% in measuring the head of water over the crest of a triangular
notch, produces an error in the discharge which is equal to
1. 1.25%
2. 1.5%
3. 2.5% 
4. 2.0%.
When water flows over a rectangular suppressed weir, the negative pressure
created beneath the nappe
1. increases the discharge
2. does not effect the discharge 
3. none of these.
4. decreases the discharge
The velocity of the fluid particle at the center of the pipe section, is
1. equal throughout
2. minimum
3. none of these.
4. Maximum 

36. For most economical rectangular section of a channel, the depth is kept
1. one-fourth of the width
2. hydraulic mean depth
3. three times the hydraulic radius
4. half the width 
To avoid vaporization, pipe lines are laid over the ridge so that these are above
the hydraulic gradient line, not more than
1. 10.0 m
2. 2.4 m
3. 6.4 m 
4. 5.0 m
In fluids, steady flow occurs when
1. conditions of flow change steadily with time
2. conditions of flow do not change with time at a point 
3. velocity vector remains constant at a point.
4. conditions of flow remain the same at adjacent point

37. Cavitation is caused by
1. Low velocity
2. High velocity
3. Low pressure 
4. High pressure
In a centrifugal pump casing, the flow of water leaving the impeller, is
1. radial flow
2. free vortex motion 
3. forced vertex.
4. rectilinear flow
If the forces are due to inertia and gravity, and frictional resistance plays only a
minor role, the design of the channels is made by comparing
1. Froude number 
2. Reynolds number
3. Weber number
4. Mach number.

38. The main assumption of Bernoulli’s equation is :
1. The velocity of energy of liquid particle, across any cross-section of a pipe is
uniform
2. No external force except the gravity acts on the liquid
3. All 
4. There is no loss of energy of the liquid while flowing
A steady uniform flow is through
1. a long pipe at decreasing rate
2. an expanding tube at increasing rate
3. an expanding tube at constant rate
4. a long pipe at constant rate 

39. Pick up the correct statement from the following :
1. Total energy gradient is the graphical representation of the total head at any
section of a pipe line
2. Vertical distance between the total energy line and hydraulic grade line is
equal to the velocity head
3. Vertical distance between the total energy line and total energy gradient
represents loss of head
4. All 
To avoid an interruption in the flow of a syphon, an air vessel is provided
1. at the inlet
2. at the summit 
3. at the outlet
4. at any point between inlet and outlet.

40. Uniform flow is said to occur when
1. frictional loss in the particular length of the channel will the more than
the drop in its elevation
2. size and shape of the cross-section change along a length
3. size and shape of the cross-section in a particular length remain constant

4. frictional loss in the particular length of the channel, will be less than the
drop in elevation.
Discharge over an ogee weir remains the same as that of
1. sharp crested weir
2. triangular weir
3. Cipoletti weir 
4. drowned weir.

41. The best side slope for most economical trapezoidal section, is
1. 30°
2. 60° 
3. 45°
4. None of these.
Cipoletti weir is a:
1. rectangular weir whose length is kept 3 times the height of the water
above sill
2. trapezoidal weir, whose sides slope 1 horizontal to 4 verticals 
3. a combination of rectangular and triangular weirs.
4. triangular weir whose notch angle is 90°
Which one of the following statements is true ?
1. All 
2. The value of kinetic energy correction factor for laminar flow is 2
3. The value of kinetic energy correction factor for turbulent flow lies
between 1.03 to 1.06
4. The practical value of kinetic energy correction factor for turbulent flow is
unity

42. On an inclined plane, center of pressure is located
1. at the centroid
2. below the centroid 
3. anywhere.
4. above the centroid
In flowing liquids Pitot tubes are used measure
1. depth
2. discharge
3. Velocity 
4. pressure
Fluids change the volume under external pressure due to
1. plasticity
2. viscosity
3. Compressibility 
4. none of these.

43. Atmospheric pressure is equal to water column head of
1. 9.81 m
2. 5.0 m
3. 7.50 m.
4. 10.30 m 
If velocities of fluid particles vary from point to point in magnitude and
direction, as well as from instant to instant, the flow is said to be
1. uniform flow
2. laminar
3. turbulent flow 
4. non-uniform flow.
Most economical section of a triangular channel, is
1. equilateral triangle
2. right angled triangle
3. isosceles triangle with 45° vertex angle
4. right angled triangle with equal sides. 

44. The following is not a laminar flow
1. Flow in beds in ground water
2. Flow of oil in measuring instruments
3. Flow in water pipe lines. 
4. Rise of water in plants through roots
Piezometers are used to measure
1. pressure in water channels, pipes etc.
2. difference in pressure at two points
3. very low pressure. 
4. atmospheric pressure

45. A vacuum gage connected to a tank reads 45 kPa at a location where the
barometric reading is 755 mm Hg. Determine the absolute pressure in the
tank. Take “ SG of Hg =13,60 “.
Answer: 55.6 kPa.
The 0.5-m-radius semi-circular gate shown in the figure is hinged through
the top edge AB. Find the required force to be applied at the center of
gravity to keep the gate closed. Answer: 11.3 kN

46. The gage pressure in a pipe is measured by a manometer containing mercury
(SG = 13.6). The top of the mercury is open to the atmosphere and the
atmospheric pressure is 100 kPa. If the mercury column height is 24 cm, the
gage pressure in the pipe is:
(a) 32 kPa (b) 24 kPa (c) 76 kPa
(d) 124 kPa (e) 68 kPa
A 2-m-long and 3-m-wide horizontal rectangular plate is submerged in water.
The distance of the top surface from the free surface is 5 m. The atmospheric
pressure is 95 kPa. Considering atmospheric pressure, the hydrostatic force
acting on the top surface of this plate is:
(a) 307 kN (b) 688 kN (c) 747 kN
(d) 864 kN (e) 2950 kN

47. A pump is used to increase the pressure of water from 100 kPa to 900 kPa at a
rate of 160 L/min. If the shaft power input to the pump is 3 kW, the efficiency
of the pump is:
(a) 0.532 (b) 0.660 (c) 0.711 (d) 0.747 (e) 0.855
A hydraulic turbine is used to generate power by using the water in a dam. The
elevation difference between the free surfaces upstream and downstream of
the dam is 120 m. The water is supplied to the turbine at a rate of 150 kg/s. If
the shaft power output from the turbine is 155 kW, the efficiency of the
turbine is:
(a) 0.77 (b) 0.80 (c) 0.82 (d) 0.85 (e) 0.88

48. Water accelerated by a nozzle to 35 m/s strikes the vertical back surface of a
cart moving horizontally at a constant velocity of 10 m/s in the flow direction.
The mass flow rate of water through the stationary nozzle is 30 kg/s. After the
strike, the water stream splatters off in all directions in the plane of the back
surface.
(a) Determine the force that needs to be applied by the brakes of the cart to
prevent it from accelerating.
(b) If this force were used to generate power instead of wasting it on the
brakes, determine the maximum amount of power that could ideally be
generated.
Answers: (a) 2536 N, (b) 5.36 kW.

49. What should be the width of a rectangular notch that should be used to
measure the water flow rate of 0.5 m3/s in an open channel. The head causing
the flow should not exceed half the notch width. Assume the coefficient of
discharge of the rectangular notch as 0.60.
(a) 0.194 (b) 0.419 (c) 0.941 (d) 0.914 (e) 0.149
𝐷𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒 𝐸𝑞𝑢𝑎𝑡𝑖𝑜𝑛 𝑄 =
2
3
𝐶𝑑 𝐵 2 𝑔 𝐻3 2
For the given values
0.5 =
2
3
× 0.60 × 𝐵 × 2 × 9.81
𝐵
2
3 2
Solving for B gives,
𝐵5 2=
0.5
0.626
= 0.799 ∴ 𝐵 = 0.914 𝑚

50. Water is transported from reservoir A to reservoirs B and C by pipe
line system shown in the figure. Determine the flow to reservoirs B
and C. Take f = 0.04. Take the total energy line at the junction is 61.5
m. (QB = 27.1 l/s, Qc = 89.9 l/s).
L = 1500 m
& D = 0.3 m
L = 1500 m
& D = 0.3 m
L = 1500 m
& D = 0.3 m
(90.0)
(60.0)
(45.0)
A
B
C
J

51. Water is transported from reservoir A to reservoirs B and C by pipe
line system shown in the figure. Determine the flow to reservoirs B
and C. Take f = 0.02 for all pipes and the total energy line at the
junction is 61.5 m.
(QB = 27.1 l/s, Qc = 89.9 l/s).
L = 700 ft & D = 8 in.
(100.0)
(70.0)
(50.0)
A
B
C
L = 1000 ft & D = 12 in. J
“1”
“2”
“3”

52. 1. For a specified roughness, beyond a certain Reynolds number the friction
factor ––––––––––. (is constant)
2. Minor losses will –––––––––– as velocity increases. (increase)
3. When a pipe of smaller diameter is converted to an equivalent pipe of
larger diameter, the length –––––––––– (increased)
4. When a pipe with a lower friction factor is converted to an equivalent pipe
with higher friction factor, the length –––––––––– (decreased)
4. When two pipes in parallel flow are replaced by a single pipe with its area
equal to the sum of the areas of the two pipes, the flow rate will –––––––––
– (increase)

53. Water flows through the screen in the pipe shown in Fig. P8.61 as
indicated. Determine the loss coefficient for the screen.

54. A circular water tank of 4 m diameter contains 5 m deep water. An orifice of 400
mm diameter is provided at its bottom.
Find the time taken for water level fall from 5 m to 2 m. Take Cd = 0.60.

55. 0.2 m
0.27 m

A smooth plastic, with an inside diameter of 20-mm is used to drain a wading
pool as shown in the figure. If viscous effects are neglected, what is the flow-
rate from the pool?

56. 0.1 m
0.2 m
D
Q
Water flows through the pipe contraction shown in the figure. For the given
0.2-m difference in the manometer level, determine the flow rate as a function
of the diameter of the small pipe, D?

57. The tank in the figure weights 500 N empty and contains 600 liters of water.
Pipes  and  have equal diameters of 6-cm and equal steady volume
flows of 300 m3/h. What should the scale reading in Newton?
Water
Scale


Scale
Water
Scale
Reading?



58. The tank in the figure weights 500 N empty and contains 600 liters of water.
Pipes  and  have equal diameters of 6-cm and equal steady volume
flows of 300 m3/h. What should the scale reading in Newton?

59. Water is withdrawn at the bottom of a large tank open to the atmosphere. The
water velocity is 6.6 m/s. The minimum height of the water in the tank is:
(a) 2.22 m (b) 3.04 m (c) 4.33 m (d) 5.75 m (e) 6.60 m
Consider a pipe that branches out into three parallel pipes and then rejoins at a
junction downstream. All three pipes have the same diameters (D = 3 cm) and
friction factors (f = 0.018). The lengths of pipe 1 and pipe 2 are 5 m and 8 m,
respectively while the velocities of the fluid in pipe 2 and pipe 3 are 2 m/s and 4
m/s, respectively. The length of pipe 3 is:
(a) 8 m (b) 5 m (c) 4 m (d) 2 m (e) 1 m

60. h = efficiency = actual output/ required input
 pump = water horsepower/shaft horsepower = WHp/ bhp
By definition, efficiency must always be less than unity. The efficiency
of a turbine is the reciprocal of the efficiency of a pump
‫التوربينات‬ ‫كفاءة‬
‫مضخة‬ ‫كفاءة‬ ‫مقلوب‬ ‫هو‬

61. A 6-cm-diameter horizontal water jet having a velocity of 25 m/s strikes a
vertical stationary flat plate. The water splatters in all directions in the plane
of the plate. How much force is required to hold the plate against the water
stream?
Answers: 1770 N

62. Consider a wide rectangular water channel with a per-unit-width flow rate of
5 m3/s. m and a Manning coefficient of n = 0.02. The channel is comprised of
a 100 m length having a slope of So,1 = 0.01 followed by a 100 m length
having a slope of So,2 = 0.02.
(a) Calculate the normal and critical depths for the two channel segments.
(b) Given an initial water depth of 1.25 m, calculate and graph the water
surface profile over the full 200 m extent of the channel. Also classify the
two channel segments (M1, A2, etc.).

63. We have during our lectures proved that the gradually varied flow equation can
be expressed as,
𝑑𝑦
𝑑𝑥
=
𝑆𝑜 − 𝑆𝐸
1 − 𝐹𝑟
2
Now, it is your turn to show that in the case of a wide rectangular channel, the
above equation can be reduced to the following form, which explicitly shows the
importance of the relationship between y, yn, and ycr:
𝑑𝑦
𝑑𝑥
=
1 −
𝑦𝑛
𝑦
10 3
1 −
𝑦𝑐𝑟
𝑦
3

64. Water is added to the tank shown in the following figure through a vertical pipe
to maintain a constant (water) level. The tank is placed on a horizontal plane
which has a frictionless surface.
Determine the horizontal force, F, required to hold the tank stationary. Neglect
all losses. (Ans. 0 N)

65. A hydraulic jump will form at 29 m downstream of sluice gate.
Water flows from under the sluice gate as shown and continues on to a free over
all. Upstream from the over fall the flow soon reaches a normal depth of 1.1 m.
The profile immediately downstream of the sluice gate is as it would be if there
were no influence from the part nearer the over fall. Will a hydraulic jump form
for these conditions?
If so, locate its position. If not, sketch the full profile and label each part. Draw
the energy grade line for the system.
20 m 20 m 20 m 20 m
15 c m 20 c m 25 c m
10 c m
31 c m
1.1 m
10 m/s
Free overfall

66. 10.23:  = 0.79 & H = 176 ft & Q = 630 gpm
10.24:  = 0.83 & H = 185 ft & Q = 820 gpm

67. 10.73: Q = 2020 gpm