TITLE.PM5

COMPRESSIBLE FLOW 899

dharm

\M-therm\Th16-2.pm5

V

V

1

2

= ρ

ρ

2

1

= ()

()

γ

γ

+

−+

1

12

12

12

M

M

...(ii)

T

T

2

1

=

[( ) ] [ ( )]

()

γγγ

γ

−+ −−

+

122 1

1

12 12

2 12

MM

M ...(iii)

Also M 22 = ()

()

γ

γγ

−+

−−

12

21

12

12

M

M

Objective Type Questions

Choose the Correct Answer :

1. All real fluids are
   (a) incompressible (b) compressible to some extent
   (c) compressible to any extent (d) none of the above.


2. A change in the state of a system at constant volume is called
   (a) isobaric process (b) isochoric process
   (c) isothermal process (d) adiabatic process.


3. A process during which no heat is transferred to or from the gas is called an
   (a) isochoric process (b) isobaric process
   (c) adiabatic process (d) isothermal process.


4. An adiabatic process is one which follows the relation
   (a) p
   ρ
   = constant (b) p
   ργ

= constant

(c) pn

ρ

= constant (n ≠ γ)(d) v = constant.

5. An isentropic flow is one which is
   (a) isothermal (b) adiabatic
   (c) adiabatic and irreversible (d) adiabatic and reversible.


6. Indica upto what Mach number can a fluid flow be considered incompressible?
   (a) 0.1 (b) 0.3
   (c) 0.8 (d) 1.0.


7. Which of the following is the basic equation of compressible fluid flow?
   (a) Continuity equation (b) Momentum equation
   (c) Energy equation (d) Equation of state
   (e) All of the above.


8. The velocity of disturbance in case of fluids is ...... the velocity of the disturbance in solids.
   (a) less than (b) equal to
   (c) more than (d) none of the above.


9. Sonic velocity (C) for adiabatic process is given as
   (a) C = γRT^3 (b) C = γRT

(c) C = γ^2 RT (d) C = γRT.

where γ = ratio of specific heats, R = gas constant, T = temperature.

10. The flow is said to be subsonic when Mach number is
    (a) equal to unity (b) less than unity
    (c) greater than unity (d) none of the above.