## Friday, February 22, 2019

### Fluid Mechanics (Objective Questions With Answers)

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01. In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow?
(A) Discharge of water by a centrifugal pump being run at a constant rpm
(B) Water flow in the suction and discharge pipe of a reciprocating pump
(C) Water discharge from a vertical vessel in which constant level is maintained
(D) Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe

02. Stoke's equation is valid in the Reynolds number range
(A) 0.01 to 0.1
(B) 0.1 to 2
(C) 2 to 10
(D) 10 to 100

03. Which of the following is the most common pump for pumping either raw sewage or sludge?
(A) Electromagnetic pump
(B) Centrifugal pump
(C) Reciprocating pump
(D) Gear pump

04. Purpose of relief valve in a reciprocating pump is to
(A) Protect the pump against developing excessive pressure
(B) Facilitate unidirectional flow of liquid
(C) Reduce the discharge pressure
(D) Control the rate of discharge

05. In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes
(A) Less than atmospheric pressure
(B) More than liquid vapor pressure
(C) Less than liquid vapor pressure
(D) More than atmospheric pressure

06. In isotropic turbulence, the __________ are equal to each other.
(A) Temporal velocity components
(B) Mean square of velocity fluctuations in the three co-ordinate directions
(C) Root mean square of velocity fluctuations in the three co-ordinate directions
(D) None of these

07. When the water is warm, the height to which it can be lifted by a pump
(A) Decreases due to reduced viscosity
(B) Decreases due to reduced vapour pressure
(C) Increases due to increased vapour pressure
(D) Decreases due to increased frictional resistance

08. What is the maximum theoretical suction lift (metres) of a reciprocating pump?
(A) 5
(B) 10
(C) 50
(D) 100

09. Pressure drop in a fluidised bed reactor is __________ that in a similar packed bed reactor.
(A) Less than
(B) Greater than
(C) Same as
(D) None of these

10. Which of the following facilitates close control of flow of fluids?
(A) Gate valve
(B) Globe valve
(C) Butterfly valve
(D) Check valve