Fluid Mechanics and Thermal Sciences - Online Test
Q1. A single degree of freedom system having mass 1 kg and stiffness 10kN/m
initially at rest is subjected to an impulse force of magnitude 5 kN for 10-4 seconds. The amplitude in mm of the resulting free vibration is
Answer : Option C
Explaination / Solution:
No Explaination.
Q2. Two large diffuse gray parallel plates, separated by a small distance, have
surface temperatures of 400 K and 300 K. If the emissivities of the surfaces are
0.8 and the Stefan-Boltzmann constant is 5.67 × 10-4 W / m2 K4, the net radiation
heat exchange rate in kW / m2 between the two plates is
Answer : Option A
Explaination / Solution:
Q3. A hinged gate of length 5 m, inclined at 30° with the horizontal and with water
mass on its left, is shown in figure below. Density of water is 1000 kg / m2. The
minimum mass of the gate in kg per unit width (perpendicular to the plane of
paper), required to keep it closed is
Answer : Option D
Explaination / Solution:
No Explaination.
Q4. The pressure, temperature and velocity of air flowing in a pipe are 5 bar, 500 K
and 50 m/s, respectively. The specific heats of air at constant pressure and at
constant volume are 1.005 kJ/kgK and 0.718 kJ/kgK, respectively. Neglect
potential energy. If the pressure and temperature of the surroundings are 1 bar
and 300 K, respectively, the available energy in kJ/kg of the air stream is
Answer : Option B
Explaination / Solution:
No Explaination.
Q5. Water (specific heat, cp = 4.18 kJ / kgK) enters a pipe at a rate of 0.01 kg/s and
a temperature of 20 C° . The pipe, of diameter 50 mm and length 3m, is
subjected to a wall heat flux 
f q''w = 2500x, where x is in m and in the direction of flow (x=0 at the inlet), the
bulk mean temperature of the water leaving the pipe in °C is
Answer : Option B
Explaination / Solution:
Q6. Water (specific heat, cp = 4.18 kJ / kgK) enters a pipe at a rate of 0.01 kg/s and a temperature of 20 C° . The pipe, of diameter 50 mm and length 3m, is subjected to a wall heat flux
If q''w = 5000, and the convection heat transfer coefficient at the pipe outlet is 1000 W / m2K, the temperature in °C at the inner surface of the pipe at the outlet
Answer : Option D
Explaination / Solution:
No Explaination.
Q7. In a simple Brayton cycle, the pressure ration is 8 and temperatures at the
entrance of compressor and turbine are 300 K and 1400 K, respectively. Both
compressor and gas turbine have isentropic efficiencies equal to 0.8. For the
gas, assume a constant value of cp (specific heat at constant pressure) equal to
1 kJ/kgK and ratio of specific heats as 1.4. Neglect changes in kinetic and
potential energies.
The power required by the compressor in kW/kg of gas flow rate is
Answer : Option C
Explaination / Solution:
Q8. In a simple Brayton cycle, the pressure ration is 8 and temperatures at the
entrance of compressor and turbine are 300 K and 1400 K, respectively. Both
compressor and gas turbine have isentropic efficiencies equal to 0.8. For the
gas, assume a constant value of cp (specific heat at constant pressure) equal to
1 kJ/kgK and ratio of specific heats as 1.4. Neglect changes in kinetic and
potential energies.
The thermal efficiency of the cycle in percentage (%) is
Answer : Option A
Explaination / Solution:
No Explaination.
Q9. If a closed system is undergoing an irreversible process, the entropy of the system
Answer : Option D
Explaination / Solution:
No Explaination.
Q10. A coolant fluid at 30°C flows over a heated flat plate maintained at a constant temperature of 100°C. The boundary layer temperature distribution at a given location on the plate may be
approximated as T = 30 + 70 exp (-y) where y (in m) is the distance normal to the plate and T is
in °C. If thermal conductivity of the fluid is 1.0W/m2K, the local convective heat transfer coefficient
(in W/ K) at that location will be
Answer : Option B
Explaination / Solution:
No Explaination.
