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WorksheetsFM & FM OBT -II SY A AY-2022-23 Sem II
Total questions: 32
Worksheet time: 17mins
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According to Darcy's formula, the loss of head due to friction in the pipeIs ------- f = coefficient of friction l = length of pipeY == average velocity of liquid in the pipe, and. d = diameter of the pipe
4flV2/ 2gd
flV2/ 2gd
4flV/ 2gd
4flV2/ gd
0.079 / Re0.25
0.316 / R0.25
64/Re
0.0025 / R0.25
V = m √i C
V = C √i m
V= AC √i m
V = m √iC
The coefficient of friction in the relation hf = 4 f l V2/2gd for laminar flow in a circular pipe was found to be 0.01. This corresponds to a flow Reynold's number equal to
400
800
1600
2000
V1 2 – V2 2 / 2g
(V1 – V2)2 / 2g
(V1 – V2/ 2g)2
0.5V2/ 2g
Kc = (1/ Cc – 1 )2
Kc=1 − Cc2
Kc = (1- Cc )2
Kc = (1/ Cc2 – 1 )2
V 2 / 2g
V12 – V22 ) / 2g
0.5V2/ 2g
0.5V2/ 4g
V2 / 2g
0.5V2/ 2g
0.5V2/ 4g
(V12 – V22) / 2g
1. The Buckingham’s-Pi theorem is widely used in the dimensional analysis
and expresses the resulting equation in terms of
the dependent and independent variables
n dimensionless parameters
(n - m) dimensionless parameters
geometric, kinematic and dynamic variables
If the number of fundamental dimensions equal 'm' then the repeating
variables shall be equal to
m and none of the repeating variables shall represent the dependent
variable.
m + 1 and one of the repeating variables shall represent the dependent
variable
m + 1 and none of the repeating variables shall represent the dependent
varia
m and one of the repeating variables shall represent the dependent
variable
Which of the following rules are used in choosing the repeating variables
in dimensional analysis?
(i) Repeating variables should include the dependent variables
(ii) Repeating variables should contain all primary units used in describing
the variables in the problem
(iii) Repeating variables should combine among themselves
(iv) Repeating variables should not contain the dependent variables.
Select the correct answer using the codes given below
Codes:
(i) and (ii)
(ii) and (iii)
(ii) and (iv)
(iii) and (iv)
1. A dimensionless group formed with variable ρ (density), ω (angular velocity), µ
(dynamic viscosity), and D (characteristic diameter) is
pωµ /D2
µ/pωD2
µD2pω
pωµD
In which of the following the friction drag is generally larger than the pressure
drag
a circular disc or plate held normally to flow
a sphere
a cylinder
an airfoil
In stream-lined bodies the drag is mainly due to
pressure
skin friction
compressibility
gravitational wave
The drag coefficient is defined by
FD / ρAU2
2 FD / ρAU2
4 FD / ρAU2
2 FD / AU2
When pressure drag over a body is large as compared to the friction drag,
then the shape of the body is that of
a bluff body
an airfort
a streamlined body
a two-dimensional body
Efficiency of power transmission through the pipe is given by
where H = total head at inlet h1= head lost due to friction
H –h1/ H
H / H + h1
H − h1 / H + h1
2H / H + h1
The length of a pipe is 1 km and its diameter is 20 cm. If the diameter of
an equivalent pipe is 40 cm, then its length is
32 km
20 km
8 km
15 km
A compound pipe with diameters d1, d2 and d3 having lengths l1, l2 and l3 is
replaced by an equivalent pipe of uniform diameter de and he
same length le as that of the compound pipe. The size of the equivalent
pipe is given by
le /de2= l1 /d12 + l2 /d22 + l3 /d32
le /de5= l1 /d15 + l2 /d25 + l3 /d35
le /de4= l1 /d14 + l2 /d24 + l3 /d34
le /de3= l1 /d13 + l2 /d23 + l3 /d33
In series-pipe problems
the head loss is the same through each pipe
the discharge is the same through each pipe
a trial solution is not necessary
the discharge through each pipe is added to obtain the total discharge
Two pipe systems are said to be equivalent when
head loss and discharge are the same in the two systems
length of pipe and discharge are the same in the two systems
friction factor and length are the same in the two systems
length and diameter are the same in the two systems
