Compressible Flow: Master Gas Behavior Under Varying Conditions

Question 1

Which of the following is a convergent-divergent nozzle?

Accepted Answer

Laval nozzle

Answer

Supersonic nozzle

Answer

Converging nozzle

Answer

Venturi nozzle

Question 2

What is the primary purpose of a diffuser in a compressible flow system?

Accepted Answer

To increase pressure

Answer

To decrease pressure

Answer

To increase velocity

Answer

To decrease velocity

Question 3

Which of the following dimensionless parameters is used to characterize compressible flow?

Accepted Answer

Mach number

Answer

Reynolds number

Answer

Prandtl number

Answer

Nusselt number

Question 4

What is the relationship between the stagnation and static temperatures for isentropic flow?

Accepted Answer

T_stagnation = T_static * (1 + (γ - 1) * M^2 / 2)

Answer

T_stagnation = T_static

Answer

T_stagnation = T_static / (1 + (γ - 1) * M^2 / 2)

Answer

T_stagnation = T_static * (1 - (γ - 1) * M^2 / 2)

Question 5

What is the shape of the Mach cone created by a supersonic object?

Accepted Answer

Conical

Answer

Spherical

Answer

Cylindrical

Answer

Parabolic

Question 6

Which of the following is a characteristic of compressible flow?

Accepted Answer

Flow can be non-adiabatic

Answer

Density remains constant with pressure and temperature

Answer

Pressure waves propagate at subsonic speeds

Answer

Viscosity plays a significant role

Question 7

In a converging-diverging nozzle, the flow will be supersonic in the:

Accepted Answer

Diverging section only

Answer

Converging section only

Answer

Both converging and diverging sections

Answer

Neither converging nor diverging section

Question 8

A flow with a Mach number less than 1 is considered to be:

Accepted Answer

Subsonic

Answer

Supersonic

Answer

Transonic

Answer

Hypersonic

Question 9

In a convergent-divergent nozzle, where does the flow reach Mach number unity?

Accepted Answer

Throat

Answer

Exit

Answer

Inlet

Answer

Nowhere

Question 10

Which of the following is a key characteristic of a diffuser?

Accepted Answer

Converts kinetic energy to pressure energy

Answer

Increases flow velocity

Answer

Decreases flow temperature

Answer

Produces a shock wave

Question 11

In a normal shock wave, what is the relationship between the upstream and downstream Mach numbers?

Accepted Answer

Upstream Mach number is always greater than downstream Mach number

Answer

Downstream Mach number is always greater than upstream Mach number

Answer

Upstream Mach number is equal to downstream Mach number

Answer

The relationship depends on the specific conditions

Question 12

What is the effect of a shock wave on the flow entropy?

Accepted Answer

Increases entropy

Answer

Decreases entropy

Answer

Does not affect entropy

Answer

Can both increase or decrease entropy

Question 13

Which of the following is NOT a type of diffuser?

Accepted Answer

Supersonic

Answer

Convergent

Answer

Divergent

Answer

Subsonic

Question 14

What is the purpose of a supersonic nozzle?

Accepted Answer

To increase the flow velocity beyond sonic speed

Answer

To decrease the flow velocity below sonic speed

Answer

To create a shock wave

Answer

To reduce the flow temperature

Question 15

A diffuser is used to convert supersonic flow into subsonic flow. Which of the following is a key design consideration for a diffuser?

Accepted Answer

Gradually increasing the area

Answer

Maintaining a constant area

Answer

Gradually decreasing the area

Answer

Using a curved surface

Question 16

Which characteristic is unique to compressible flow compared to incompressible flow?

Accepted Answer

Mach number can exceed unity

Answer

Density variation is negligible

Answer

Velocity remains relatively constant

Answer

Pressure is independent of temperature

Question 17

In an isentropic flow process, which property remains unchanged?

Accepted Answer

Entropy

Answer

Temperature

Answer

Velocity

Answer

Pressure

Question 18

A shock wave is characterized by:

Accepted Answer

Sudden jump in flow properties

Answer

Continuous change in flow properties

Answer

Decrease in pressure and temperature

Answer

Increase in entropy

Question 19

In a normal shock wave, the Mach number downstream is:

Accepted Answer

Always less than 1

Answer

Always greater than 1

Answer

Equal to 1

Answer

Cannot be determined without additional information

Question 20

In a diffuser, the flow velocity typically:

Accepted Answer

Decreases

Answer

Increases

Answer

Remains constant

Answer

Varies based on the diffuser design

Question 21

What is the maximum velocity attainable in a converging nozzle?

Accepted Answer

Speed of sound

Answer

Twice the speed of sound

Answer

Three times the speed of sound

Answer

Sonic velocity

Question 22

What is the effect of a shock wave on flow parameters?

Accepted Answer

Increases entropy and decreases velocity

Answer

Decreases entropy and increases velocity

Answer

Increases both entropy and velocity

Answer

Decreases both entropy and velocity

Question 23

What is the purpose of a Laval nozzle?

Accepted Answer

To accelerate a fluid to supersonic speeds

Answer

To decelerate a fluid from supersonic to subsonic speeds

Answer

To regulate the flow rate of a fluid

Answer

To mix two fluids

Question 24

Which of the following is NOT a type of shock wave?

Accepted Answer

De Laval shock

Answer

Normal shock

Answer

Oblique shock

Answer

Expansion shock

Question 25

What is the significance of the Prandtl-Meyer expansion fan?

Accepted Answer

It describes the supersonic flow around a sharp corner

Answer

It predicts the pressure drop in a diverging nozzle

Answer

It determines the maximum flow rate through a convergent-divergent nozzle

Answer

It explains the formation of shock waves

Question 26

Which of the following is NOT an assumption of isentropic flow analysis?

Accepted Answer

Irreversible

Answer

Adiabatic

Answer

Frictionless

Answer

Constant enthalpy

Question 27

Which of the following equations is commonly used to calculate the pressure ratio across a normal shock wave in compressible flow?

Accepted Answer

Rankine-Hugoniot equation

Answer

Bernoulli equation

Answer

Euler equation

Answer

Navier-Stokes equation

Question 28

Which of the following properties remains constant across a reversible adiabatic flow process?

Accepted Answer

Entropy

Answer

Temperature

Answer

Pressure

Answer

Density

Question 29

In isentropic flow, which of the following quantities remains constant?

Accepted Answer

Entropy

Answer

Temperature

Answer

Velocity

Answer

Pressure

Question 30

Which type of nozzle is employed to accelerate a gas to supersonic speeds?

Accepted Answer

Convergent-Divergent

Answer

Convergent

Answer

Divergent

Answer

Venturi

Question 31

Which of the following factors does NOT influence the propagation speed of a shock wave?

Accepted Answer

Gas viscosity

Answer

Gas pressure

Answer

Gas temperature

Answer

Gas density

Question 32

Which of the following is NOT a distinctive characteristic of a shock wave?

Accepted Answer

Isentropic

Answer

Supersonic

Answer

Compressive

Answer

Associated with sudden entropy rise

Question 33

What is the Mach number at the throat of a converging nozzle?

Accepted Answer

1

Answer

1.5

Answer

1.2

Answer

0.5

Question 34

Which device is specifically designed to expand supersonic flow?

Accepted Answer

Diverging nozzle

Answer

Converging nozzle

Answer

Venturi

Answer

Pipe

Question 35

What is the total pressure change experienced in a subsonic diffuser?

Accepted Answer

Increase

Answer

Zero

Answer

Cannot be determined

Answer

Decrease

Question 36

How does a normal shock wave impact the velocity of the flow passing through it?

Accepted Answer

Causes a decrease in velocity

Answer

Causes an increase in velocity

Answer

Causes oscillations in velocity

Answer

No change in velocity

Question 37

What is the nature of the pressure drop experienced across a shock wave in supersonic flow?

Accepted Answer

Irreversible

Answer

Adiabatic

Answer

Isentropic

Answer

Reversible

Question 38

Which set of equations can be employed to calculate the pressure ratio across a normal shock wave?

Accepted Answer

Rankine-Hugoniot equations

Answer

Euler equations

Answer

Bernoulli equation

Answer

Navier-Stokes equations

Question 39

Which characteristic defines compressible flow?

Accepted Answer

Significant changes in density with pressure and temperature variations

Answer

Absence of shock waves

Answer

Negligible changes in velocity with distance

Question 40

In a diffuser, the flow velocity:

Accepted Answer

Decreases

Answer

Increases

Answer

Becomes supersonic

Answer

Remains constant

Question 41

Which of the following is NOT a dimensionless parameter used in compressible flow analysis?

Accepted Answer

Reynolds number

Answer

Mach number

Answer

Prandtl number

Question 42

A supersonic flow is characterized by a Mach number that is:

Accepted Answer

Greater than 1

Answer

Equal to 1

Answer

Less than 1

Question 43

In an isentropic flow through a converging-diverging nozzle, the critical pressure ratio is defined as:

Accepted Answer

The pressure ratio at which the flow velocity at the throat reaches the speed of sound (Mach 1)

Answer

The pressure ratio at which the flow becomes supersonic throughout the nozzle

Answer

The pressure ratio at which the flow velocity at the exit reaches the speed of sound (Mach 1)

Question 44

A shock wave is characterized by a:

Accepted Answer

Sudden and sharp increase in pressure and temperature over a very short distance

Answer

Region of constant pressure and temperature

Answer

Gradual change in pressure and temperature

Question 45

Which of the following is NOT a characteristic of an isentropic flow?

Accepted Answer

Irreversible heat transfer

Answer

Adiabatic

Answer

Reversible

Answer

Frictionless

Question 46

A diffuser is a device designed to:

Accepted Answer

Slow down a supersonic flow and increase its pressure

Answer

Speed up a supersonic flow and decrease its pressure

Answer

Slow down a subsonic flow and decrease its pressure

Question 47

When a converging-diverging nozzle operates under choked conditions, the Mach number at the throat is:

Accepted Answer

1

Answer

Greater than 1

Answer

Zero

Answer

Less than 1

Question 48

The stagnation temperature of a compressible flow is defined as:

Accepted Answer

The temperature the flow would have if brought to rest isentropically (without any heat loss or friction)

Answer

The temperature at which the flow becomes sonic

Answer

The actual temperature of the flow

Question 49

The Fanno flow model is primarily used in compressible flow analysis to:

Accepted Answer

Analyze the flow of a compressible fluid in a constant area duct with friction

Answer

Analyze the flow with heat transfer in a constant area duct

Answer

Analyze the flow with variable area in a frictionless duct

Question 50

Which of the following is a major application of compressible flow principles?

Accepted Answer

Design of jet engines

Answer

Design of gears

Answer

Design of hydraulic systems

Question 51

The Prandtl-Meyer expansion wave is a phenomenon observed in:

Accepted Answer

Supersonic flow around a sharp corner

Answer

Flow through a converging nozzle

Answer

Flow through a diffuser

Answer

Subsonic flow around a corner