R10
Code No: R21014
SET - 1
II B. Tech I Semester Regular Examinations, March - 2014
FLUID MECHANICS
(Civil Engineering)
Time: 3 hours
Max. Marks: 75
Answer any FIVE Questions
All Questions carry Equal Marks
1. a) The specific gravity of a liquid is 3.0, what are its specific weight, specific mass and
specific volume?
b) A body weighing 45 kg with a flat surface area of 930 cm2 slides down lubricated inclined
plane making a 30° angle with the horizontal. For viscosity of 1 poise and body speed of
3 m/sec, determine the lubricant film thickness.
(7M+9M)
2. a) A tank 20 m deep and 9 m wide is layered with 8 m of oil, 6 m of water and 4 m of mercury.
Determine the total hydrostatic force and resultant centre of pressure on the side. Specific
gravity of oil is 0.881 and that of mercury is 13.6.
b) Obtain simplified expressions for the centre of pressure of vertical planes. i) plate ii) circle
iii) triangle
(8M+7M)
3. a) Define and distinguish between i) steady and unsteady flow,
flow,
ii) uniform and non-uniform
iii) rotational and irrotational flow.
b) Differentiate between tangential and normal acceleration and find out the expressions for
both.
(8M+7M)
4. a) A converging pipe is 22 cm inlet and 12 cm outlet and 6 m long is lying in the vertical plane
making an angle 450 to the horizontal. The pipe is carrying the water 24 m3/ min. The
pressure of the water at the inlet is 500 kPa, find the pressure of the water at the exit.
b) What is Euler’s equation of motion? How will you obtain Bernoulli’s equation from it?
(8M+7M)
5. a) Find the difference in drag force exerted on a flat plate of size 2.5 m × 2.5 m when the plate
is moving at a speed of 4 m/s normal to its plane in : i) water, ii) air of density 1.24 kg/m3.
Co-efficient of drag is given as 1.15.
b) Explain the characteristics of laminar and turbulent boundary layers.
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(8M+7M)
Code No: R21014
R10
SET - 1
6. a) Derive an expression for mean velocity for laminar flow through a pipe
b) The population of a city is 8,00,000 and is to be supplied with water from a reservoir 6.4 km
away. Water is to be supplied at the rate of 140 liters per head per day and half the supply is
to be delivered in 8 hours. The full supply level of the reservoir is R.L. 180.00 and its lowest
water level is R.L. 105.00. The delivery end of the main is at R.L. 22.50 and the head
required there is 12 m. Find the diameter of the pipe. Take f = 0.04.
(7M+8M)
7. a) A pipe of 25 cm in diameter and 500 m long is carrying oil whose sp.gr.= 0.82 and  =0.075
poise. The oil flow rate is 110 liters/sec. Find the head lost in the pipe and power
required to maintain the flow.
b) Why are the pipes connected in parallel? What is the loss of head in pipes of same length
which are connected in parallel?
(8M+7M)
8. a) A venture meter is to be fitted in a pipe of 25 cm diameter where the pressure head is 7.6 m
of flowing liquid and the maximum flow is 8200 liters per minute. Find the least diameter of
the throat to ensure that the pressure head does not become negative. Take Cd =0.96.
b) Explain the principle involved in measuring velocity of flow using a Pitot static tube.
(8M+7M)
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Code No: R21014
R10
SET - 2
II B. Tech I Semester Regular Examinations, March - 2014
FLUID MECHANICS
(Civil Engineering)
Time: 3 hours
Max. Marks: 75
Answer any FIVE Questions
All Questions carry Equal Marks
1.
a) Two large planes are parallel to each other and are inclined at 30° to the horizontal with the
space between them filled with a fluid of viscosity 20 cp. A small thin plate of 0.125 m
square slides parallel and midway between the planes and reaches a constant velocity of
2 m/s. The weight of the plate is 1 N. Determine the distance between the plates.
b) Derive expressions from basics for the pressure inside a droplet and a free jet.
(8M+7M)
2. a) A water tank is provided with a gate which has a shape of a quadrant of a circle of 3 m
radius. The gate is positioned in such a way that one straight edge of it is horizontal.
Determine the force acting on the gate due to water and its point of action if the tank is filled
with water up to 2 m above the edge.
b) Explain importance of the study of fluid forces on surfaces and submerged bodies. (8M+7M)
3.
4.
5.
a) Define and distinguish between streamline, path line and streak line.
b) List out different types of flows and note down the basic differences also.
(8M+7M)
a) The momentum equation of the fluid flow is obtained by using Newton’s second law of
motion then prove that
∑ Fx Q(V 2xV1x ) and ∑ Fy Q[V2y V 1y]
b) A liquid of specific gravity 1.3 flows in a pipe at a rate of 800 l/s, from point 1 to point 2
which is 1 m above point 1. The diameters at section 1 and 2 are 0.6 m and 0.3 m
respectively. If the pressure at section 1 is 10 bar, determine the pressure at section 2.
(8M+7M)
a) Derive Von Karman momentum integral equation.
b) Calculate the friction drag on a plate 15 cm wide and 45 cm long placed longitudinally in a
stream of oil (sp. gr. 0.925 and kinematic viscosity 0.9 stokes) flowing with a free stream
velocity of 6 m/sec. Also find the thickness of the boundary layer and shear stress at the
trailing edge.
(8M+7M)
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Code No: R21014
R10
SET - 2
6. a) Distinguish between laminar flow and turbulent flow in pipes.
b) A pipeline 22.5 cm in diameter and 1580 m long has a slope of 1 in 200 for the first 790 m
and 1 in 100 for the next 790 m. the pressure at the upper end of the pipeline is 1.1 kg/cm 2
and the lower end is 0.55 kg/cm2. Take f = 0.032 determine discharge through the pipe.
(7M+8M)
7. a) What is a siphon? Why is it used? Explain its working.
b) A pipe of 45 cm diameter carries an oil 460 liters/sec. If the pipe length is 110 m, find the
head loss due to friction. Take =0.45 stokes for the oil.
(8M+7M)
8. a) A horizontal venturimeter with inlet diameter 22 cm and throat diameter 12 cm is used to
measure the flow of water. The pressure at inlet is 17.658 N/cm2 and the vacuum pressure at
the throat is 30 cm of mercury. Find the discharge of water through venturimeter. Take
Cd=0.98.
b) What is a weir? How are the weirs classified? What is the difference between a sharp crested
and a broad crested weir?
(8M+7M)
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R10
Code No: R21014
SET - 3
II B. Tech I Semester Regular Examinations, March - 2014
FLUID MECHANICS
(Civil Engineering)
Time: 3 hours
Max. Marks: 75
Answer any FIVE Questions
All Questions carry Equal Marks
1. a)
A shaft of 150 mm diameter rotates in bearings with a uniform oil film of thickness 0.8
mm. Two bearings of 15 cm width are used. The viscosity of the oil is 22 Centipoises.
Determine the torque if the speed is 210 rpm.
b) Explain how vacuum pressure can be measured with the help of a U-tube manometer.
(8M+7M)
2. a) Show that in the case of a rectangle inclined to the horizontal, immersed in a fluid with its
centroid at a depth, h i) the horizontal component of the resultant force equals the force on the
vertical projection of the area and
ii) the vertical component equals the weight of the fluid
column above this area.
b) A tank contains mercury up to a height of 0.3 m over which water stands to a depth of 1 m
and oil of specific gravity 0.8 stands to a depth of 0.5 m over water. For a width of 1 m
determine the total pressure and also the point of action of the same.
(8M+7M)
3. a) The flow field is given by
  x3 y
Check whether the given field exists or not? Further check whether it is irrotational?
b) Differentiate between tangential and normal acceleration and find out the expressions for
both.
(8M+7M)
4.
a) 250 liters/s of water is flowing in a pipe having a diameter of 300 mm. If the pipe is bent by
135° (that is change from initial to final direction is 135°), find the magnitude and direction of the
resultant force on the bend. The pressure of water flowing is 39.24N/cm2.
b) What is Euler’s equation of motion? How will you obtain Bernoulli’s equation from it?
(8M+7M)
5.
a) A man weight 85 kgf descends to the ground from an aero plane with the help of parachute
against the resistance of air. The velocity with which the parachute, which is hemispherical in
shape, comes down is 20 m/s. Find the diameter of the parachute. Assume CD=0.5 and density of
air = 1.25 kg/m3.
b) What do you mean by boundary layer separation? What is the effect of pressure gradient on
boundary layer separation?
(8M+7M)
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Code No: R21014
R10
SET - 3
6.
a) A liquid of sp.gr.=0.9 and  =1 poise is filled between two horizontal plates 1 cm apart. If
the upper plat is moving with a velocity of 2.5 m/s, determine the shear stress at the moving
plate. The pressure difference between the two sections 10 m a apart along the flow is 9000
N/m2.
b) Derive an expression for mean velocity for laminar flow between parallel plates.
(8M+7M)
7.
a) Explain various minor losses in pipes.
b) A pipe of 350 m long and 22 cm in diameter is carrying water. The loss of pressure head
measured in 3.2 m. Take f =0.008. Find out the rate of flow through the pipe.
(8M+7M)
8.
a) A venture-meter is provided to measure the water flowing through a horizontal pipe of
25 cm diameter. The throat of the venture- meter is 10cm. The pressure of water flowing through
the pipe is 1.5 bar and the vacuum measured at the throat is 30 cm of Hg. Find the water flow rate
through the pipe. Take Cd=0.975.
b) What is a notch ? How are the notches classified?
(8M+7M)
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Code No: R21014
R10
SET - 4
II B. Tech I Semester Regular Examinations, March - 2014
FLUID MECHANICS
(Civil Engineering)
Time: 3 hours
Max. Marks: 75
Answer any FIVE Questions
All Questions carry Equal Marks
1.
a) Two large vertical plane parallel surfaces are 5 mm apart and the space between them is
filled with a fluid. A thin plate of 12.5 cm square falls freely between the planes along the
central plane and reaches a steady velocity of 2 m/s. Determine the weight of the plate if the
viscosity of the fluid filling the space is 0.02 Ns/m2.
b) Distinguish between Newtonian and non Newtonian Fluids.
(7M+8M)
2.
a) Obtain simplified expressions for the centre of pressure of vertical planes. i) plate ii) circle
iii) triangle.
b) Derive an expression for the depth of center of pressure from free surface of liquid of an
inclined plane surface sub-merged in the liquid.
(8M+7M)
3.
a) What is meant by one-dimensional, two-dimensional and three-dimensional flows?
b) A velocity potential function for two dimensional steady state flow is given by
 x( 2 y 1)
Find out the velocity at the point P (2, 3)
Also find out the value of stream function passing through the point P.
(8M+7M)
4.
A bend in pipeline conveying water gradually reduces from 60 cm to 30 cm diameter and
deflects the flow through angle of 55°. At the larger end the gage pressure is 1.75 kg/cm 2.
Determine the magnitude and direction of the force exerted on the bend when the flow is 876
liters per sec.
(15 M)
5.
a) What are the different methods of preventing the separation of boundary layer?
b) A kite 0.9 m X 0.9 m weighing 0.4 kgf (3.924 N) assumes an angle of 12° to the horizontal.
The string attached to the kite makes an angle of 450 to the horizontal. The pull on the string
is 2.5 kgf (24.525 N) when the wind is flowing at a speed of 30 km/hour. Find the
corresponding co-efficient of drag and lift. Density of air is given as 1.25 kg/m3. (8M+7M)
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Code No: R21014
R10
SET - 4
6.
a) What do you understand by Reynold’s number? Mention its significance in fluid
mechanics.
b) An oil is flowing between two parallel plates kept at 12 cm apart with maximum velocity of
1.5 m/s. Find out the discharge per meter width (perpendicular to paper), shear stress at the
plates; the pressure difference between two points 20 m apart along the flow direction. Also
find out the velocity gradient at the plates and velocity at 2 cm from the plate surface. Take
 (for oil) = 25 poise.
(8M+7M)
7.
a) Define the terms i) Hydraulic gradient line and
ii) Total energy line
b) What do you understand by transmission efficiency of a pipe? Obtain a condition for
maximum efficiency and prove that it is 66.7%.
(8M+7M)
8.
a) A sharp- crested weir is 1 m high and provided to a rectangular channel of 8 m wide. The
discharge measured by the weir is 3.5m3/s. Find the depth of the water upstream of the weir. Take
Cd=0.62.
b) Derive the expression for computing discharge through a Venturimeter.
(7M+8M)
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