Steam and Gas Turbines Multiple Choice Questions on “Effect of Compressibility”.
1. When mach number is less than 1 flow is __________
a) Subsonic flow
b) Transonic flow
c) Supersonic flow
d) None of the mentioned
Answer: a
Clarification: For subsonic flow mach number is always less than one.
2. When mach number is equal to one then the flow is ___________
a) Subsonic flow
b) Transonic flow
c) Supersonic flow
d) None of the mentioned
Answer: b
Clarification: For transonic flow mach number is equal to one.
3. When mach number is greater than one flow is ___________
a) Subsonic flow
b) Transonic flow
c) Supersonic flow
d) None of the mentioned
Answer: c
Clarification: For supersonic flow mach number is always greater than one.
4. For subsonic flow density varies relatively.
a) True
b) False
Answer: b
Clarification: For subsonic flow density is relatively constant.
5. For transonic flow density change is ________ velocity change.
a) equal to
b) more than
c) less than
d) none of the mentioned
Answer: a
Clarification: For transonic flow density change is almost equal to velocity change.
6. For supersonic flow density changes ___________ velocity change.
a) faster than
b) slower than
c) equal to
d) none of the mentioned
Answer: a
Clarification: For supersonic flow density change is faster than velocity change.
7. In a supersonic flow density change is faster than velocity change by a factor of _________
a) Mach number
b) Square of mach number
c) Cube of mach number
d) None of the mentioned
Answer: b
Clarification: In supersonic flow density change is greater than velocity change by a factor of square of mach number.
8. For compressible flow mach number must be ____________ 0.3.
a) less than
b) equal to
c) greater than
d) none of the mentioned
Answer: c
Clarification: For compressible flow mach number should be greater than 0.3.
9. When normal shock waves occurring at an angle ____________ 90 degree then they are called as bow shock.
a) less than
b) greater than
c) equal to
d) none of the mentioned
Answer: b
Clarification: When normal shock waves occurring at an angle less than 90 degree they are called as oblique shock waves.
10. When oblique shock _________ the flow it is called as a bow shock.
a) detached from
b) added to
c) minimizes
d) none of the mentioned
Answer: a
Clarification: Due to flow conditions oblique shock may be attached or detached with flow, When oblique shock wave is detached with the flow it forms a bow shock.