Fluid Mechanics Sample Question paper

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Register No.: …………..…………………….
KPR Institute of Engineering and Technology
(Autonomous)
Avinashi Road, Arasur, Coimbatore - 641 407
Dept.: CIVIL
Ac.Yr. : 2021 – 2022
Course Code & Title : U19CE303 FLUID MECHANICS
Year : II Semester : 03 Date : 08.01.2022 - FN
CIAT : IV Duration : 2 hour 30 minutes Maximum Marks : 100
Q
No
Section - A (10 x 10 = 100 Marks)
Answer All Questions
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1
The space between two parallel plates 5 mm apart is filled with crude oil. A
force of 2 N is required to drag the upper plate at a constant velocity of 0.8 m/s.
The lower plate is stationary. The area of the upper plate is 0.09 m2. Determine:
(i) The dynamic viscosity, and (ii) the kinematic viscosity of the oil in stokes if
the specific gravity of oil is 0.9
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2
Inside a 60 mm diameter cylinder a piston of 59 mm diameter rotates
concentrically. Both the cylinder and piston are 80 mm long. If the space
between the cylinder and piston is filled with oil of viscosity of 0.3 N.s/m2 and a
torque of 1.5 Nm is applied, find: (i) The r.p.m. of the piston, and (ii) The power
required.
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3
In a two-dimensional flow field for an incompressible fluid the velocity
components are: u=y3/3+2x-x2y, v=xy2-2y-x3/3 .Find an expression for the
stream function ψ
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4
The water is flowing through a pipe having diameters 200 mm and 100 mm at
sections 1 and 2 respectively. The rate of flow through the pipe is 35 litres/s.
The section 1 is 6 m above datum and section 2 is 4 m above datum. If the
pressure at section 1 is 400 kN/m2 , find the intensity of pressure at section 2.
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5
In a circular pipe of diameter 100 mm a fluid of viscosity 7 poise and sp. gr. 1.3
is flowing. If the maximum shear stress at the wall of the pipe is 196.2 N/m2 ,
find: (i) The pressure gradient, (ii) The average velocity, and (iii) Reynolds
number of flow
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6
The discharge of water through a horizontal pipe is 0·25 m3/s. Its diameter,
which is 200 mm, suddenly enlarges to 400 mm. If the intensity of pressure of
water in the smaller pipe is 120 kN/m2, determine : (i) Loss of head due to
sudden enlargement, (ii) Intensity of pressure in the large pipe, and (iii) Power
lost due to enlargement.
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7
Find the ratio of displacement thickness to momentum thickness and
momentum thick ness to energy thickness for the velocity distribution in the
boundary layer given by u/U = 2 (y/δ) – (y/δ)2
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8
A plate of length 500 mm and width 250 mm has been placed longitudinally in a
stream of crude oil, which flows, with a velocity of 6 m/s. If the oil has a specific
gravity of 0.9 and kinematic viscosity of 1 stoke, calculate: (i) Boundary layer
thickness at the middle of plate, (ii) Shear stress at the middle of plate, and (iii)
Friction drag on one side of the plate.
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9
The resistance R, to the motion of a completely submerged body depends upon
the length of the body L, velocity of flow V, mass density of fluid ρ and kinematic
viscosity of fluid ν. By dimensional analysis prove that R = ρV2L2ᵠ(VL/v)
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QP CODE

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10
In an aeroplane model of size 1/50 of its prototype the pressure drop is 4x105
N/m2. The model is tested in water. Find the corresponding pressure drop in the
prototype. Take specific height of air = 0.0124 kN/m3. The viscosity of water is
0.01 poise while the viscosity of air is 0.00018 poise
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