Fluid Mechanics for Chemical Quiz 3

1 / 50

Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.) ?

d2/3

d1/3

2 / 50

Capacity of a hydraulic accumulator is defined in terms of maximum_______?

Volume available in the cylinder

Rate of falling of ram

Amount of energy stored

Flow rate through accumulator

3 / 50

Boundary layer thickness in turbulent flow over a flat plate increases as(where, d = distance from the leading edge.) ?

d4/5

d2/3

d1/3

4 / 50

Critical velocity in a pipe flow__________?

Increases as fluid viscosity increases

Independent of fluid density

None of these

Increases as pipe diameter increases

5 / 50

Differential manometer measures the______?

Atmospheric pressure

Sub-atmospheric pressure

None of these

Pressure difference between two points

6 / 50

Check valve is used for _________ flow?

Unidirectional

Very precise control of

None of these

Multidirectional

7 / 50

Boundary layer separation occurs when the______?

Pressure reaches a minimum

Velocity of sound is reached

Valve is closed in a pipeline

Cross-section of the channel is reduced

8 / 50

Dimension of surface tension is (where, F = force, L = length) ?

FL-1

F-2. L

F-1. L

F.L-2

9 / 50

Choose the set of pressure intensities that are equivalent ?

4.33 psi, 10 ft. of water, 20.7 inches of Hg

10 psi, 19.7 ft. of water, 23.3 inches of Hg

4.33 psi, 10 ft. of water, 8.83 inches of Hg

10 psi, 19.7 ft. of water, 5.3 inches of Hg

10 / 50

Design of the casing of centrifugal pump should be such as to minimise the_________?

Loss of static head

Back flow through impeller

None of these

Loss of kinetic head

11 / 50

Capacity of a rotary gear pump can be varied by___________?

Bleeding air into suction

Bypassing liquid from the suction or discharge line

All A., B. and C.

Changing the speed of rotation

12 / 50

Cavitation in a centrifugal pump can be avoided by keeping the___________?

Outlet pressure high

Inlet pressure low

Inlet pressure high

Outlet pressure low

13 / 50

Diaphragm pumps are used to transport__________?

Liquids

Slurries

Fluids

Solids

14 / 50

Cd is always _______ Cc?

Equal to

Greater than

Either more or less than

Less than

15 / 50

Buckingham-? theorem states that in any physical problem including ?n? quantities having ?m? dimensions, the quantities can be arranged into ______ independent dimensionless parameters?

n-m

n/m

16 / 50

Cavitation occurs in a centrifugal pump when the suction pressure is_________?

Equal to the developed head

Equal to the vapour pressure

Greater than the vapour pressure of the liquid at that temperature

Less than the vapour pressure of the liquid at that temperature

17 / 50

Dimension of absolute viscosity is__________?

MLT-1

MLT

ML-1T

ML-1T-1

18 / 50

Centrifugal compressors compared to reciprocating compressors___________?

Have quieter operation

All A., B. and C.

Have lower operating costs

Require less space

19 / 50

Cp/Cv is termed as___________?

Prandtl number

Weber number

Mach number

Adiabatic constant

20 / 50

Check valves are used________?

For unidirectional flow

For controlling water flow

In bends

At high pressure

21 / 50

Choose the correct set of dimensions of viscosity that are equivalent (where, F, M, L, T are dimensions for force, mass, length and time respectively) ?

ML-1T-3, F-1L2T

FL-2T, ML-1T-1

FLT, ML-1T-1

F-1L2T-1, MLT-3

22 / 50

Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, ? = surface tension of mercury)______?

1/?

1/d

23 / 50

Deformation drag, which is caused by widespread deformation of fluid around the immersed body______?

Occurs when NRe is very small

Depends mainly on cross-sectional shape

Is independent of body length

Is primarily a friction drag

24 / 50

Cavitation in a pump creates so many undesirable effects. Out of the following, which is not an undesirable effect created by cavitation ?

Develops noise

Increase in thrust

Decrease in effect

Develops high pressure

25 / 50

Centre of pressure in an immersed body is _______ the centre of gravity?

Either above or below; depends on the liquid density

Above

Below

26 / 50

Brownian movement is prominent in the particle size range of ______ microns in case of settling of a particle in a fluid?

100 to 1000

0.01 to 0.10

200 to 300

2 to 3

27 / 50

Curve III in the bellow diagram represents a/an_________?

None of these

Pseudo plastic fluid

Dilatent fluid

Ideal plastic

28 / 50

Cocks are used to control _____?

Any liquid

Water

None of these

Solids

29 / 50

Centrifugal pump can?t be used to pump _______?

Molten sodium (used as a coolant in Fast Breeder Reactor)

Thick molten soap at 80?C

Moderately viscous vegetable oil used in soap industry

None of the above

30 / 50

Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f1 and that for smooth pipe is f2. Pick out the correct statement ?

f1 = f2

f1 > f2

f1 < f2

Data not sufficient to relate f1 & f2

31 / 50

Choking in case of pipe flow means that a_____?

Specified mass flow rate cannot be achieved

None of these

Valve is closed in the line

Restriction in flow cross-section area occurs

32 / 50

Colebrook equation for friction factor in turbulent flow is given by, f-0.5 = -4 loge [(?/D) + (1.26/NRe ?F). It reduces to Nikuradse equation for a value of (?/D) equal to ___________?

0.5

33 / 50

Differential manometer measures the_____?

Pressure gradient

Absolute pressure

Gauge pressure

Pressure difference

34 / 50

Centre of pressure of a plane surface of arbitrary shape immersed vertically in a static mass of fluid_________?

Is independent of the specific weight of the fluid

Is at the centroid of the plane surface

Lies above the centroid of the plane surface

Is different for different fluids

35 / 50

Creeping flow around a sphere is defined, when particle Reynolds number is_____?

< 500

> 2.5

< 0.1

< 2100

36 / 50

Co-efficient of discharge (Cd) is defined as actual discharge/theoretical discharge and is equal to Cc . Cv; where Cc = Co-efficient of contraction and Cv = co-efficient of velocity. Cd of an orifice is usually about___________?

0.42

0.98

0.62

0.82

37 / 50

Check in a centrifugal pump is_________?

Generally a globe valve

Provided in the discharge line

All A., B. and C.

Provided to prevent liquid from backing up through the pump when the pump is turned off or accidently stops running

38 / 50

Centrifugal pump is normally classified on the basis of the_________?

Number of blades in impeller

Type of casing

Impeller blade angle

rpm

39 / 50

Buoyant force___________?

Depends on the weight of the floating body

Depends on the depth of the submergence of the floating body

None of these

For non-symmetrical bodies is not vertical

40 / 50

Dimension of kinematic viscosity is_______?

MLT-1

L2T

L2T-2

L2T-1

41 / 50

Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of constant density at a particular discharge capacity. With decrease in the capacity of the pump, the ________ decreases?

BHP required by the pump

All A., B. and C.

Head of the liquid pumped

NPSH required

42 / 50

Diaphragm valves are used for handling ________ fluids?

Corrosive

Solid suspended

Non-Newtonian

Viscous

43 / 50

Disc compensators are provided in large diameter fuel gas carrying pipelines to__________?

Account for contraction/expansion of pipe due to temperature changes of the surroundings

Make the pipe joint leak-proof

Keep the pipe in proper orientation

Account for the pressure variation side the pipeline

44 / 50

Co-efficient of velocity is _____ the coefficient of discharge?

Not related to

More than

Equal to

Less than

45 / 50

Cd for the orifice plate varies from _____?

0.58 to 0.8

0.93 to 0.98

0.02 to 0.03

0.2 to 0.3

46 / 50

Check valve provided in the discharge line of a centrifugal pump serves the purpose of controlling the________?

Discharge pressure

Back flow of fluid in the event of stoppage of pump

All A., B. and C.

Flow of liquid during operation of the pump

47 / 50

Centrifugal pumps as compared to reciprocating pumps___________?

Deliver fluid with pulsating/fluctuating discharge

Can be run with discharge line valve closed for a short interval

Do not need priming

Run at a lower speed for the same discharge

48 / 50

Cavitation can be prevented by_________?

Maintaining the suction head sufficiently greater than the vapour pressure

Suitably designing the pump

Maintaining suction head = developed head

Maintaining suction head lower than the vapour pressure

49 / 50

Dean number is concerned with the______?

Psychrometry

Power consumption in agitated vessels

Fluid flow through helical pipes

Fluid-particle interaction

50 / 50

Capillary tube method of viscosity measurement is based on the _________?

Navier-stokes equation

Stoke?s law

None of these

Hagen-Poiseuille?s equation

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