Velocity profile
for a Bingham plastic fluid flowing (under laminar conditions) in a pipe is
(A)
Parabolic
(B)
Flat
(C)
Flat near the wall and parabolic in the
middle
(D)
Parabolic near the wall and flat in the
middle
(GATE 2002)
Answer: (D)
A lubricant 100
times more viscous than water would have a viscosity (in Pa.S)
(A)
0.01
(B)
0.1
(C)
1
(D)
10
(GATE 2002)
Answer: (B)
The inlet
velocity of water (ρ = 1000 kg/m3) in a right angled bed reducer is
V1=1 m/s, as shown below. The inlet diameter is D1 = 0.8
m and outlet diameter D2 = 0.4 m. The flow is turbulent and the
velocity profiles at the inlet and outlet are flat (plug flow). Gravitational
forces are negligible.
(A)
7500 N/m2
(B)
8000 N/m2
(C)
8500 N/m2
(D)
9000 N/m2
(GATE 2001)
Answer: (A)
The operation of
a rotameter is based on
(A)
Variable flow area
(B)
Rotation of a turbine
(C)
Pressure drop across a nozzle
(D)
Pressure at a stagnation point
(GATE 2001)
Answer: (A)
A Bingham fluid
of viscosity µ = 10 Pa.s and a yield stress τ0 = 10 Kpa, is sheared
between flat parallel plates separated by a distance 10-3 m. The top
plate is moving with a velocity of 1 m/s. The shear stress on the plate is
(A)
10 Kpa
(B)
20 kpa
(C)
30 Kpa
(D)
40Kpa
(GATE 2001)
Answer: (B)
For laminar flow
of shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the
pressure gradient will increase by a factor of
(A)
2
(B)
<2
(C)
>2
(D)
½
(GATE 2000)
Answer: (B)
A pipe of ID 4 m
is bifurcated into two pipes of ID 2 m each. If the average velocity of water
flowing through the main pipe is 5 m/s, the average velocity through the
bifurcated pipes is
(A)
20 m/s
(B)
10 m/s
(C)
7.07 m/s
(D)
5 m/s
(GATE 1999)
Answer: (B)
In centrifugal
pumps, cavitation occurs when pressure of the impeller eye or vane becomes
(A)
Less than atmospheric pressure
(B)
More than liquid vapour pressure
(C)
Less than liquid vapour pressure
(D)
More than atmospheric pressure
(GATE 1999)
Answer: (C)
For a laminar
flow through a packed bed the pressure drop is proportional to (Vs
is superficial liquid and Dp is the particle diameter).
(GATE 1999)
Answer: (A)
For flow through
a horizontal system, the ratio of exit pressure to inlet pressure is found to
be greater than one.
(A)
The system is converging pipe line
(B)
The system is a diverging pipeline
(C)
The system is a pipeline of uniform
diameter
(D)
The observation is not possible
(GATE 1998)
Answer: (B)
Boundary layer
separation is characterized by one of the following conditions given below,
where Re is the Reynolds number for flow. Select the appropriate conditions.
(A)
Re << 1, accelerating flow
(B)
Re >> 1, accelerating flow
(C)
Re << 1, decelerating flow
(D)
Re >> 1, decelerating flow
(GATE 1998)
Answer: (D)
A globe valve is
most suitable for application in which
(A)
The valve is required to be either fully
open or fully closed
(B)
Flow control is required
(C)
The fluid contains dispersed particles
(D)
One-way flow is required
(GATE 1998)
Answer: (B)
For a laminar
flow of a fluid through a packed bed of spheres of diameter ‘d’, the pressure
drop per unit length of bed depends upon the sphere diameter as
(A)
D
(B)
D2
(C)
D4
(D)
1/D2
(GATE 1997)
Answer: (D)
A 0.5 m high bed
made up of a 1 mm diameter glass spheres (density 2500 kg/m3) is to
be fluidized by water (density 2500 kg/m3). If at the point of
incipient fluidization, the bed voidage is 40%, the pressure drop across the
bed is
(A)
4.4 Kpa
(B)
2.94 Kpa
(C)
3.7 Kpa
(D)
1.5 Kpa
(GATE 1997)
Answer: (A)
Two iron pipes
of the same nominal diameter but different schedule numbers will have
(A)
The same inside diameter
(B)
The same outside diameter
(C)
The same wall thickness
(D)
None of the above
(GATE 1997)
Answer: (B)
The hydraulic
radius for flow in a rectangular duct of cross-sectional dimensions H, W is
(GATE 1998)
Answer: (B)
The hydraulic
diameter of an annulus of inner and outer radii Ri and Ro
respectively is
(GATE 1997)
Answer: (C)
For the laminar
flow of a fluid in a circular pipe of radius R, the Hagen-Poiseulle equation
predicts that volumetric flow rate to be proportional to
(A)
R
(B)
R2
(C)
R4
(D)
R0.5
(GATE 1997)
Answer: (C)
A rotameter
through which air at room temperature and atmospheric pressure is flowing,
gives a certain reading for a flow rate of 100 cc/s. If helium (molecular
weight is 4) is used and the rotameter shows the same reading the flow rate is
(A)
26 cc/s
(B)
42 cc/s
(C)
269 cc/s
(D)
325 cc/s
(GATE 1996)
Answer: (C)
Tooth paste is
(A)
Bingham plastic
(B)
Pseudoplastic
(C)
Newtonian fluid
(D)
Dilatant fluid
(GATE
1996)
Answer: (A)
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