PTU Punjab Technical University B-Tech May 2019 Question Papers 4th Semester Mechanical Engineering (MECH)
Total No. of Pages : 02
Total No. of Questions : 09
B.Tech.(ME) (2011 Onwards) (Sem.?4)
FLUID MECHANICS
Subject Code : BTME-403
M.Code : 59131
Time : 3 Hrs. Max. Marks : 60
INSTRUCTION TO CANDIDATES :
1.
SECTION-A is COMPULSORY consisting of TEN questions carrying T WO marks
each.
2.
SECTION-B contains FIVE questions carrying FIVE marks each and students
have to attempt any FOUR questions.
3.
SECTION-C contains T HREE questions carrying T EN marks each and students
have to attempt any T WO questions.
SECTION-A
1.
Write in short on following :
(i)
Define Velocity potential function.
(ii)
Define Mach number.
(iii) Write Beroulli's equation
(iv)
Explain Differential Manometers.
(v)
Explain Dynamic Viscosity
(vi)
Kinematic Viscosity.
(vii) Laminar boundary layer.
(Viii) Pathlines, Steaklines and Streamlines
(ix)
Rotational and irrotational flow
(x)
Meta Centre
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SECTION-B
Q.2
The velocity componenet of a 2-D incompressible flow tiled are expressed as :
u = (y3/3) + 2x ? x2y and v = xy3 + (?2y) ? (x3/3)
(i) Is the flow physically Possible?
(ii) What is the discharge between stream lines passing through (1.3) and (2, 3)?
(iii) Is the flow irrotational?
Q.3
Find the convective acceleration at the middle of a pipe which converges uniformly from
0.4 m diameter to 0.2 m diameter over 2 m length. The rate of flow is 20 lit/s. If the rate
of flow changes uniformly from 201/s to 401/s in 30 seconds, find the total acceleration
at the middle of the pipe at 15th second.
Q.4
Dervie the Bernaulli's theorem along with its assumptions. How it is modified for
practical applications?
Q.5
A horizontal venturimeter with inlet diameter 30 cm and throat diameter 10 cm is used to
measure the flow of water. The pressure intensity at the inlet is 13.734 N/cm2 while the
vacuum pressure head at the throat is 37 cm of mercury. Find the rate of flow. Find also
the value of Cd for the venturimeter. assume that 4% of the differential head is lost
between the inlet and throat.
Q.6
An external cylindrical mouthpiece of diameter 150 mm is discharging water under a
constant head of 6 m. Determine the discharge and absolute pressure head of water at
vena-contracta. Take Cd = 0.855 and Cc for vena contracta = 0.62. Atmospheric pressure
head = 10.3 m of water.
SECTION-C
Q.7
A body has the cylindrical upper portion of 3 m diameter and 1.8 m deep. The lower
portion is a curved one, Which displaces a volume of 0.6 m3 of water. The centre of
buoyancy of the curved portion is at a distance of 1.95 m below the top of the cylinder.
The centre of gravity of the whole body is 1.20 m below the top of the cylinder. The total
displacement of water is 3.9 tonnes. Find the meta-centric height of the body.
Q.8
For a town water supply, the main pipe line of diameter 0.4 m is required. As pipes more
than 0.35 m diameter are not readily available, two parallel pipes of same diameter were
used for water supply. If the total discharge in the parallel pipe is same as in the single
main pipe. Find the diameter of the parallel pipe. Assume the co-efficient of friction same
for all pipes.
Q.9
The frictional torque T of a disc of diameter D rotating at a speed N in a fluid of viscosity
and density in a turbulent flow is given bv
5
2
T D N
.
2
D N
Prove this by the method of dimensions.
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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This post was last modified on 04 November 2019