Fluid Mechanics and Thermal Sciences - Online Test
Q1. For flow through a pipe of radius R, the velocity and temperature distribution are as follows:
where C1 and C2 are constants 
with Um being the mean velocity of flow. The value of Tm is
where C1 and C2 are constants with Um being the mean velocity of flow. The value of Tm is
Answer : Option C
Explaination / Solution:
Q2.
The speed of an engine varies from 210 rad/s to 190 rad/s. During the cycle the
change in kinetic energy is found to be 400 Nm. The inertia of the flywheel in
kg/m2 is
Answer : Option A
Explaination / Solution:
No Explaination.
Q3. Steam enters an adiabatic turbine operating at steady state with an enthalpy of 3251.0 kJ/kg and
leaves as a saturated mixture at 15 kPa with quality (dryness fraction) 0.9. The enthalpies of the
saturated liquid and vapor at 15 kPa are hf = 225.94 kJ/kg and hg = 2598.3 kJ/kg respectively.
The mass flow rate of steam is 10 kg/s. Kinetic and potential energy changes are negligible. The
power output of the turbine in MW is
Answer : Option C
Explaination / Solution:
Q4. Oil flows through a 200 mm diameter horizontal cast iron pipe (friction factor, f = 0.0225) of
length 500 m. The volumetric flow rate is 0.2 m3/s. The head loss (in m) due to friction is (assume g = 9.81 m/s2)
Answer : Option A
Explaination / Solution:
4f = 0.0225 
L = 500 m
Q = 0.2 m3/s
Q5. An ideal gas of mass m and temperature T1 undergoes a reversible isothermal process from an
initial pressure P1 to final pressure P2. The heat loss during the process is Q. The entropy change ∆S of the gas is
Answer : Option B
Explaination / Solution:
No Explaination.
Q6. Which one of the following configurations has the highest fin effectiveness?
Answer : Option A
Explaination / Solution:
For a given configuration, Thin, closely spaced fins can achieve maximum heat transfer area.
Hence, more effective.
Q7. The velocity triangles at the inlet and exit of the rotor of a turbo-machine are shown. V denotes
the absolute velocity of the fluid, W denotes the relative velocity of the fluid and U denotes the
blade velocity. Subscripts 1 and 2 refer to inlet and outlet respectively. If V2 = W1 and V1 = W2,
then the degree of reaction is
Answer : Option C
Explaination / Solution:
No Explaination.
Q8. A room contains 35 kg of dry air and 0.5 kg of water vapor. The total pressure and temperature of
air in the room are 100 kPa and 25℃ respectively. Given that the saturation pressure for water at
25℃ is 3.17 kPa, the relative humidity of the air in the room is
Answer : Option D
Explaination / Solution:
No Explaination.
Q9. An incompressible fluid flows over a flat plate with zero pressure gradients. The boundary layer
thickness is 1 mm at a location where the Reynolds number is 1000. If the velocity of the fluid
alone is increased by a factor of 4, then the boundary layer thickness at the same location, in mm
will be
Answer : Option C
Explaination / Solution:
No Explaination.
Q10. A solid steel cube constrained on all six faces is heated so that the temperature rises uniformly by
∆T. If the thermal coefficient of the material is α. Young’s modulus is E and the Poissons’s ratio
is υ, the thermal stress developed in the cube due to heating is
Answer : Option A
Explaination / Solution:
No Explaination.
