Test: Compressible Flow & Flow Through Open Channel - 2 - Mechanical Engineering MCQ

In isentropic flow between two points, the stagnation:[ 

For one-dimensional is entropic flow in a diverging passage, if the initial static pressure is P₁ and the initial Mach number is M₁ ( (M₁ < 1),then for the down stream flow  

Consider the following statements: 
1. De Laval nozzle is a subsonic nozzle.
2. Supersonic nozzle is a converging passage.
3. Subsonic diffuser is a diverging passage.
Which of these statements is/are correct?

The critical pressure ratios for the flow of dry saturated and superheated steam through a nozzle are respectively.  

If the cross-section of a nozzle is increasing in the direction of flow insupersonic flow, then in the down stream direction. 

Steam pressures at the inlet and exit of a nozzle are 16 bar and 5·2 barrespectively and discharge is 0·28 m³/s. Critical pressure ratio is 0.5475.If the exit pressure is reduced to 3·2 bar then what will be the flow ratein m³/s?  

Assertion (A): For pressure ratio greater than the critical pressure ratio, a convergent-divergent nozzle is required.  
Reason (R): Divergent portion increases the flow area which increasesthe mass flow rate.

Shear stress in a turbulent flow is due to:  

Reynolds stress may be defined as the 

Consider the following statements regarding a hydraulic jump:
1. There occurs a transformation of super critical flow to sub-criticalflow.  
2. The flow is uniform and pressure distribution is due to hydrostatic force before and after the jump.
3. There occurs a loss of energy due to eddy formation and turbulence.
Which of these statements are correct?

A convergent divergent nozzle is designed for a throat pressure 2.2MPa. If the pressure at the exit is 2.3 MPa, then the nature of the flow at the exit will be: 

Consider the following statements for compressible flow through avarying area passage: 
1. For a convergent nozzle, if the exit pressure is less than critical,external flow will not be isentropic.
2. Supersonic-subsonic diffuser would appear similar to nozzle and works without irreversibility.
Which of the statements given above is/are correct?

Which one of the following is proper for a normal shock wave?

Which of the following parameters decrease across a normal shock wave?  
1. Mach number
2. Static pressure
3. Stagnation pressure
4. Static temperature
Select the correct answer using the codes given below:

Assertion (A): A convergent-divergent nozzle may give supersonic orsubsonic flow at the exit even if the throat is choked.  
Reason (R): Depending on the back pressure ratio P_b/P_o the divergent part of the nozzle may act as a supersonic nozzle or a subsonic diffuser.

In a normal shock in a gas, the:  

Across a normal shock wave in a converging-diverging nozzle foradiabatic flow, which of the following relations are valid? 

In a normal shock in a gas:  

The fluid property that remains unchanged across a normal shockwave is:

A normal shock:  

Consider the following statements pertaining to one-dimensional isentropic flow in a convergent-divergent passage  
1. A convergent-divergent passage may function as a supersonicnozzle or a venturi depending on the back pressure.
2. At the throat, sonic conditions exits for subsonic or supersonic flowat the outlet.
3. A supersonic nozzle discharges fluid at constant rate even if the exit pressure is lower than the design pressure.
4. A normal shock appears in the diverging section of the nozzle if the back pressure is above the design pressure but below a certain minimum pressure for venturi operation.
Which of these statements are correct?

Consider the following statements: 
Across the normal shock, the fluid properties change in such a mannerthat the
1. Velocity of flow is subsonic
2. Pressure increases
3. Specific volume decreases
4. Temperature decreasesOf these correct statements are

Which one of the following is correct?  
In a normal shock wave in one dimensional flow,

Assertion (A): A normal shock wave can occur at any section in aconvergent-divergent nozzle. 
Reason (R): A normal shock wave occurs only when the flow of the fluidis supersonic and the subsequent flow after the shock is subsonic.

Assertion (A): A normal shock always makes a supersonic flow of acompressible fluid subsonic, but an oblique shock may not ensure subsonic flow after the shock.  
Reason (R): A normal shock reduces the stagnation pressure and stagnation enthalpy considerably whereas the loss at oblique shock isminimized.

A converging diverging nozzle is connected to a gas pipeline.  
At the inlet of the nozzle (converging section) the Mach number is
2. Itis observed that there is a shock in the diverging section.
What is thevalue of the Mach number at the throat?

Introduction of a Pitot tube in a supersonic flow would produce