There is a simplest explaination of fluid mechanics

1. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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Minia University
Faculty of Engineering
Civil Eng. Dept. / 2nd
Year Civil.
Hydraulic I (CVE 215)
Date: Feb. 19, 2019
Time: Three hours
 Answer all the following questions,
 Assume any missing data reasonably,
 Net sketches and clear dimensions are required.
‫من‬ ‫مكون‬ ‫الامتحان‬
‫ثالثة‬
‫ورق‬
‫ات‬
،
‫ا‬‫لك‬
‫مه‬
‫م‬
‫وهجني‬
&
‫و‬
‫العظمي‬ ‫الهاية‬
70
‫درجة‬
Question No. 1 “16 Marks”
1. The flow in pipe is laminar if.........
a) Reynolds number is equal to 2400,
b) Reynolds number is equal to 4000,
c) Reynolds number is more than 2400,
d) None of the above.
2. A stream line is a line......
a) Which is along the path of a particle,
b) Which is always parallel to the main direction of flow,
c) Across which there is no flow,
d) On which tangent drawn at any point gives the direction of
velocity.
3. For Flood control and irrigation applications the pump generally
used is.......
a) Centrifugal type,
b) Reciprocating type,
c) Axial flow type,
d) Radial flow type.
4. Cavitation in hydraulic turbine results in.......
a) Noise and vibration,
b) Reduction of discharge,
c) Drop in output and efficiency,
d) Rough surface.

2. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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5. Pump transfers the mechanical energy of a motor or of an engine
into _________ of a fluid.
a) pressure energy,
b) kinetic energy,
c) either pressure energy or kinetic energy,
d) pressure energy, kinetic energy or both.
6. Which of the following is true?
a) the slope of EGL will always be greater than that of the axis
of the pipe,
b) the slope of EGL will always be smaller than that of the
axis of the pipe,
c) the slope of EGL will always be equal to that of the axis of
the pipe,
d) the slope of EGL will always be independent of that of the
axis of the pipe.
7. The vertical intercept between EGL and HGL is equal to
a) pressure head,
b) potential head,
c) kinetic head,
d) Piezometric head.
8. Which of the following is true?
a) HGL always drops in the direction of flow,
b) HGL always rises in the direction of flow,
c) HGL always remains constant in the direction of flow,
d) HGL may or may not in the direction of flow.
9. The head loss at the entrance of the pipe is that at it’s exit equal
to;
a) one,
b) half,
c) twice,
d) four times.

3. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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10. The frictional resistance for fluids in motion is
a) proportional to the velocity in laminar flow and to the
square of the velocity in turbulent flow,
b) proportional to the square of the velocity in laminar flow
and to the velocity in turbulent flow,
c) proportional to the velocity in both laminar flow and
turbulent flow,
d) proportional to the square of the velocity in both laminar
flow and turbulent flow.
11)Which one of the following is correct?
a) Darcy-Weisbach formula is generally used for head loss in
flow through both pipes and open channels
b) Chezy’s formula is generally used for head loss in flow
through both pipes and open channels
c) Darcy-Weisbach formula is generally used for head loss in
flow through both pipes and Chezy’s formula for open
channels
d) Chezy’s formula is generally used for head loss in flow
through both pipes and Darcy-Weisbach formula for open
channels.
12.A liquid flows through two similar pipes 1 and 2. If the ratio of
their flow velocities V
1
: V
2
be 2:3, what will be the ratio of the
head loss in the two pipes?
a) 3:2
b) 9:4
c) 2:3
d) 4:9
13.The pressure of the liquid flowing through the divergent portion of
a Venturi meter,
a) Remains constant,

4. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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b) Increases,
c) Decreases,
d) Depends upon mass of liquid.
14.The error in discharge (dQ/Q) to the error in measurement of head
(dH/H) over a triangular notch is given by:
a) dQ / Q = 3/2 × (dH/H),
b) dQ / Q = 2 × (dH/H),
c) dQ / Q = 5/2 × (dH/H),
d) dQ / Q = 3 × (dH/H).
15.A compound pipe is required to be replaced by a new pipe.
The two pipes are said to be equivalent, if:
a) length of both the pipes is same,
b) diameter of both the pipes is same,
c) loss of head and discharge of both the pipes is same,
d) loss of head and velocity of flow in both the pipes is same.
16.An air vessel is provided at the summit in a syphon to:
a) avoid interruption in the flow,
b) increase discharge,
c) increase velocity,
d) maintain pressure difference.
Question No. 2 “14 Marks”
For the container shown in the figure,
 Estimate the resultant force on the hemispherical bottom.

5. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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Question No. 3 “14 Marks”
A sluice gate is used to control the water flow rate over a dam. The
gate is 20 ft wide, and the depth of the water above the bottom of the
sluice gate is 16 ft. The depth of the water upstream of the gate is 20
ft, and the depth downstream is 3 ft.
 Estimate the flow rate under the gate and the force on the gate.

6. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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Question No. 4 “16 Marks”
A tank has two identical orifices on one of its vertical sides. The upper
orifice is 4 m below the water surface and lower one is 6 m below the
water surface. If the value of C
v
, for each orifice is 0.98,
 Find the point of intersection of the two jets.
Question No. 5 “15 Marks”
An elevated open water tank is used to supply water to a building
located 5000 ft away as shown in the figure. The water is carried
through a 12-inch cast iron pipe (f =0.045) with a flow rate of 2.25
cfs. Fire codes require that a pressure of 30 psi be available on the
second floor of the building which is at an elevation of 20 ft above a
reference datum.
 What is the required elevation of the water in the tank relative
to the reference datum?

7. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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With best wishes and 
Dr. Ezzat El-Sayed G. SALEH

8. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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With best wishes and 
Dr. Ezzat El-Sayed G. SALEH

9. CVE 215 – 2 YEAR CIVIL – FIRST SEMESTER “FEB. 2019”
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