Question Bank for Railways NTPC (Technical Ability) Fluid Mechanics and Machinery Fluid Mechanics

1)

Hydrodynamic and thermal boundary layer thickness are equal for Prandtl number:

A)

Equal to zero

B)

Less than 1

C)

Equal to 1

D)

More than 1

View Solution

2)

In a rotameter as the flow rate increases, the float:

A)

Rotates at higher speed

B)

Rotates at lower speed

C)

Rises in the tube

D)

Drops in the tube

View Solution

3)

A two-dimensional fluid flow is described by the velocity components \[u=5{{x}^{3}},\] \[v=-\,15{{x}^{2}}\,y.\] The stream function at point will be:

A)

\[2\,{{\text{m}}^{\text{2}}}\text{/s}\]

B)

\[2\,{{\text{m}}^{3}}\text{/s}\]

C)

\[10\,{{\text{m}}^{3}}\text{/s}\]

D)

\[20\,{{\text{m}}^{3}}\text{/s}\]

View Solution

4)

Match the following:

List-I		List-II
A.	Circular sewer maximum discharge	1.	Y= 0.938 D
B.	Maximum velocity in circular sewer	2.	Y=0.81 D
C.	Triangular Channel	3.	\[{{y}_{c}}=\frac{4}{5}\,E,\] \[\frac{v_{c}^{2}}{2g}=\frac{{{y}_{c}}}{4}\]
D.	Bourdon gauge	4.	\[{{y}_{c}}=\frac{2}{3}\,E,\] \[\frac{v_{c}^{2}}{2g}=\frac{{{y}_{c}}}{4}\]

Codes:

A)

A\[\to \]4, B\[\to \]3, C\[\to \]2, D\[\to \]1

B)

A\[\to \]3, B\[\to \]4, C\[\to \]1, D\[\to \]2

C)

A\[\to \]2, B\[\to \]3, C\[\to \]1, D\[\to \]4

D)

A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3

View Solution

5)

Aging of pipe implies:

A)

Pipe becoming smoother with time

B)

Relative roughness decreasing periodically

C)

Increase in absolute roughness periodically with time

D)

Increase in absolute roughness linearly with time

View Solution

6)

A nozzle has velocity head at outlet of 10m. If it is kept vertical the height reached by the stream is:

A)

100 m

B)

10 m

C)

\[\sqrt{10}\,m\]

D)

\[\frac{1}{\sqrt{10}}\]

View Solution

7)

Laminar sub-layer may develop during flow over a flat-plate. It exists in:

A)

Laminar zone

B)

Transition zone

C)

Turbulent zone

D)

Laminar and transition zone

View Solution

8)

The velocity components for a two dimensional incompressible flow of a fluid are \[u=x-4y.\] and \[v=-y-4x.\] It can be concluded that:

A)

The flow does not satisfy the continuity equation

B)

The flow is rotational

C)

The flow is irrotational

D)

None of the above

View Solution

9)

A \[\frac{1}{25}\] model of a ship it to be tested for estimating the wave drag. If the speed of the prototype is 1.0 m/s, then the speed at which the model must be tested is:

A)

0.04 m/s

B)

0.2 m/s

C)

5.0 m/s

D)

25.0 m/s

View Solution

10)

In which of the following cases frictional drag is predominating?

A)

1 and 2 only

B)

2 and 3

C)

2, 3 and 4 only

D)

1, 2 and 3 only

View Solution

11)

Match the following:

List-I		List-II
A.	Wave drage of a ship	1.	Cavitation in pumps and turbines
B.	Pressure coefficient	2.	\[\rho \,r.r\,{{L}^{3}}r\]
C.	Thoma numbers	3.	Re = 0.1
D.	Stokes Law	4.	\[\frac{\Delta \,p}{\rho \,{{\text{V}}^{\text{2}}}\text{/}\,\text{2}}\]

Codes:

A)

A\[\to \]1, B\[\to \]2, C\[\to \]4, D\[\to \]3

B)

A\[\to \]4, B\[\to \]3, C\[\to \]1, D\[\to \]2

C)

A\[\to \]1, B\[\to \]3, C\[\to \]4, D\[\to \]3

D)

A\[\to \]2, B\[\to \]4, C\[\to \]1, D\[\to \]2

View Solution

12)

The terminal velocity of small sphere falling in a viscous fluid is:

A)

Proportional to the diameter of the sphere

B)

Inversely proportional to the viscosity of the fluid

C)

Inversely proportional to the diameter of the sphere

D)

Proportional to the density of the fluid.

View Solution

13)

Which of the following statement is true?

A)

For an ideal fluid \[\mu =0.\] \[\rho =0\] constant, K =0

B)

A floating body is in stable, unstable or neutral equilibrium according to as the metacentric height is zero, positive or negative.

C)

The exact analysis of viscous flow problems can be made by Euler's equation

D)

The most economical diameter of a pipe is the one for which the annual fixed cost and annual power cost (to overcome friction) are minimum.

View Solution

14)

Which of the following statements is false?

A)

The lift force (per unit length) on a body depends on the density of the fluid

B)

For laminar flow through a pipe, the loss of head is directly proportional to velocity as well as viscosity of fluid

C)

A hydraulic jump occurs when a supercritical flow comes across sub critical flow

D)

At the stall point for the airfoil, the lift is minimum and the drag decreases sharply beyond it.

View Solution

15)

Which of the following is not a dimensionless group?

A)

\[\frac{\Delta \,p}{\rho \,{{N}^{2}}{{D}^{2}}}\]

B)

\[\frac{g\,H}{{{N}^{2}}\,{{D}^{2}}}\]

C)

\[\frac{\rho \,\omega \,{{D}^{2}}}{\mu }\]

D)

\[\frac{\Delta \,p}{\rho \,{{V}^{3}}}\]

View Solution

16)

For a real fluid moving with uniform velocity, the pressure:

A)

Depends upon depth and orientation

B)

is independent of depth but depends upon orientation

C)

is independent of orientation but depends upon depth

D)

is independent of both depth and orientation

View Solution

17)

Consider the following assumptions:

1. Steady flow

2. In viscid flow

3. Flow along a stream line

4. Conservative force field

For an ideal fluid, which of the statements are correct?

A)

1 and 2

B)

1, 2 and 4

C)

2, 3 and 4

D)

1, 3 and 4

View Solution

18)

The vertical component of force on a curved surface submerged in a static liquid is to the:

A)

Mass of the liquid above the curved surface

B)

Weight of the liquid above curved surface

C)

Product of pressure at C.G. multiplied by the area of the curved surface

D)

Product of pressure at C.G. multiplied by the projected area of the curved surface

View Solution

19)

A pipe friction test shows that, over the range of speeds used for the test, the non-dimensional friction factor \['f'\] varies inversely with Reynolds Number. From this, one can conclude that the:

A)

Fluid must be compressible

B)

Fluid must be ideal

C)

Pipe must be smooth

D)

Flow must be laminar

View Solution

20)

Chezy's formula is given by (m, i, C and V are, respectively, the hydraulic mean depth, slope of the channel, Chezy's constant and average velocity of flow)

A)

\[V=i\sqrt{mC}\]

B)

\[V=C\sqrt{i\,m}\]

C)

\[V=m\sqrt{i\,C}\]

D)

\[V=\sqrt{m\,i\,C}\]

View Solution

21)

The standard sea level atmospheric pressure is equivalent to:

A)

10.2 m of freshwater of \[\rho =998\,\,\text{kg/}{{\text{m}}^{\text{3}}}\]

B)

10.2 m of salt water \[\rho =1025\,\,\text{kg/}{{\text{m}}^{\text{3}}}\]

C)

25.5 m of kerosene of \[\rho =800\,\,\text{kg/}{{\text{m}}^{\text{3}}}\]

D)

6.4 m of carbon tetrachloride of \[\rho =1590\,\,\text{kg/}{{\text{m}}^{\text{3}}}\]

View Solution

22)

Which one of the following represents equilibrium of a static fluid? (Symbols have the usual meaning)

A)

\[\frac{dp}{dz}=-\frac{\rho }{g}\]

B)

\[\frac{dp}{g}\,=\,-\,\frac{dz}{\rho }\]

C)

\[\rho \,dp=-\frac{dz}{g}\]

D)

\[\frac{dp}{\rho }=-g\,dz\]

View Solution

23)

A tank with four equal vertical faces of width/ and depth h is filled up with a liquid. If the force on any vertical side is equal to the force at the bottom, then value of \[\frac{h}{l}\] will be:

A)

2

B)

\[\sqrt{2}\]

C)

1

D)

\[\frac{1}{2}\]

View Solution

24)

Match. List-I (Physical properties of fluid) with List-II (Dimension/Definitions) and select the correct answer using codes given below the Lists:

List-I		List-II
A.	Absolute viscosity	1.	\[\frac{du}{dy}\] is constant
B.	Kinematic viscosity	2.	Newton per metre
C.	Newtonian fluid	3.	Poise
D.	Surface tension	4.	\[\frac{Stress}{Strain}\] constant
		5.	Strokes

Codes:

A)

A\[\to \]5, B\[\to \]3, C\[\to \]2, D\[\to \]1

B)

A\[\to \]3, B\[\to \]5, C\[\to \]2, D\[\to \]4

C)

A\[\to \]5, B\[\to \]3, C\[\to \]4, D\[\to \]2

D)

A\[\to \]3, B\[\to \]5, C\[\to \]1, D\[\to \]2

View Solution

25)

If the governing equation for a flow field is given by \[{{\nabla }^{2}}\phi \,=\,0\] and the velocity is given by \[\overrightarrow{V}\,=\,\nabla \phi ,\] the:

A)

\[\nabla \times \overrightarrow{\nabla }=0\]

B)

\[\nabla \times \overrightarrow{V}=1\]

C)

\[{{\nabla }^{2}}\times \overrightarrow{\nabla }=1\]

D)

\[(\overrightarrow{\nabla }.\nabla )\,\overrightarrow{\nabla }=\frac{\partial \,\overrightarrow{\nabla }}{\partial \,t}\]

View Solution

26)

Which one of the following equations represents the continuity equation for steady compressible fluid flow?

A)

\[\nabla .\rho \,\overline{V}+\frac{\partial \rho }{\partial \,t}=0\]

B)

\[\nabla .\rho \,\overline{V}+\frac{\partial \rho }{\partial \,t}=0\]

C)

\[\nabla .\overline{V}=0\]

D)

\[\nabla .\rho \,\overline{V}=0\]

View Solution

27)

A liquid of specific gravity 0.82 flows with a velocity 4.4 m/s. Its velocity head is:

A)

0.82 m

B)

4.43 m

C)

1 m

D)

19.6 m

View Solution

28)

Match List-I with List-II and select the correct answer using the codes given below the Lists:

List-I		List-II
A.	Orifice meter	1.	Measurement of flow in channel
B.	Broad creasted weir	2.	Measurement of velocity in a pipe/ channel
C.	Pitol tube	3.	Measurement of flow in a pipe of may inclination
D.	Rotameter	4.	Measurement of upward flow in a vertical pipe

Codes:

A)

A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]2

B)

A\[\to \]1, B\[\to \]3, C\[\to \]2, D\[\to \]4

C)

A\[\to \]3, B\[\to \]1, C\[\to \]2, D\[\to \]4

D)

A\[\to \]1, B\[\to \]3, C\[\to \]4, D\[\to \]2

View Solution

29)

Decrease in temperature, in general, results in:

A)

An increase in viscosities of both gases and liquids

B)

A decrease in the viscosity of liquids and gases

C)

An increase in the viscosity of liquids and an decrease in that of gases

D)

A decrease in the viscosity of liquids and an increase in that of gases

View Solution

30)

Consider the following statements:

(1) Streak line indicates instantaneous position of particles of fluid passing through a point.

(2) Streamlines are paths traced by a fluid particle with constant velocity.

(3) Fluid particles cornot cross streamlines irrespective of the type of flow.

(4) Streamlines converge as the fluid is accelerated, and diverge when retarded.

Which of these statements are correct?

A)

1 and 4

B)

1, 3 and 4

C)

1, 2, and 4

D)

2 and 3

View Solution

31)

If the diameter of a capillary tube is doubled, the capillary-rise will become:

A)

\[\sqrt{2}\] Times less

B)

Double

C)

Half

D)

\[\sqrt{2}\]Times more

View Solution

32)

A stepped pipeline with four different cross-sections discharges water at the rate of 2 litres per second. Match List-I (Areas of pipe is sq. cm) with List-II (velocities of water in cm/s) and select the correct answer using the codes given below the list:

List-I		List-II
A.	500	1.	4
B.	100	2.	5
C.	400	3.	10
D.	200	4.	15
		5.	20

Codes:

A)

A\[\to \]5, B\[\to \]1, C\[\to \]2, D\[\to \]3

B)

A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3

C)

A\[\to \]1, B\[\to \]4, C\[\to \]3, D\[\to \]4

D)

A\[\to \]3, B\[\to \]2, C\[\to \]5, D\[\to \]1

View Solution

33)

Fluid flow rate Q, can be measured easily with the help of a venturi tube, in which the difference of two pressures, \[\Delta \,P,\] measured at an upstream point and at the smallest cross-section of the tube, is used. If a relation \[\Delta \,P\propto {{Q}^{n}}\] exists, then n is equal to:

A)

\[\frac{1}{3}\]

B)

\[\frac{1}{2}\]

C)

1

D)

2

View Solution

34)

The drag force D on a certain object in a certain flow is a function of the coefficient of viscosity p, the flow speed, V and the body dimension L (for geometrically similar objects); then D is proportional to:

A)

\[L\,\mu \,V\]

B)

\[\frac{{{\mu }^{2}}{{V}^{2}}}{{{L}^{2}}}\]

C)

\[{{\mu }^{2}}{{V}^{2}}{{L}^{2}}\]

D)

\[\frac{\mu \,L}{V}\]

View Solution

35)

A metallic piece weighs 80 N in air and 60 N in water. The relative density of the metallic piece is about:

A)

8

B)

6

C)

4

D)

2

View Solution

36)

Match List-I (Nature of equilibrium of floating body) with List-II (Conditions for equilibrium) and select the correct answer using the codes given below the lists:

List-I (Nature of equilibrium of floating body)		List-II (Conditions for equilibrium)
A.	Unstable equilibrium	1.	\[\overline{MG}\,\,=\,\,0\]
B.	Netutral equilibrium	2.	M is above G M is below G
C.	Stable equilibrium	4.	\[\overline{BG}\,\,=\,\,0\]

Where M, G and B are metacentre, Centre of gravity and Centre of buoyancy respectively. Codes:

A)

A\[\to \]1, B\[\to \]3, C\[\to \]2

B)

A\[\to \]3, B\[\to \]1, C\[\to \]2

C)

A\[\to \]1, B\[\to \]3, C\[\to \]4

D)

A\[\to \]4, B\[\to \]2, C\[\to \]3

View Solution

37)

The velocity potential function in a two dimensional flow fluid is given by \[\phi ={{x}^{2}}-{{y}^{2}}.\] The magnitude of velocity at the point (1, 1) as:

A)

2

B)

4

C)

\[2\,\sqrt{2}\]

D)

\[4\,\sqrt{2}\]

View Solution

38)

The relations between shear stress \[\left( \tau \right)\] and velocity gradient for ideal fluids, Newtonian fluids and non-Newtonian fluids are given below. Select the correct combination:

A)

\[\tau =0\,;\] \[\tau =\mu \,{{\left( \frac{du}{dy} \right)}^{2}};\] \[\tau =\mu \,{{\left( \frac{du}{dv} \right)}^{3}}\]

B)

\[\tau =0\,;\] \[\tau =\mu \,{{\left( \frac{du}{dy} \right)}^{2}}\,;\] \[\tau =\mu \,{{\left( \frac{du}{dy} \right)}^{2}}\]

C)

\[\tau =\mu \,\left( \frac{du}{dy} \right)\,\,;\] \[\tau =\mu \,{{\left( \frac{du}{dy} \right)}^{2}};\] \[\tau =\mu \,{{\left( \frac{du}{dy} \right)}^{3}}\]

D)

\[\tau =\mu \,\left( \frac{du}{dy} \right)\,;\] \[\tau =\mu \,{{\left( \frac{du}{dy} \right)}^{2}};\] \[\tau =0\]

View Solution

39)

Consider the following statements:

1. For stream function to exist, the flow should be irrotational.

2. Potential functions are possible even though continuity is not satisfied.

3. Stremlines diverge where the flow is accelerated.

4. Bernoulli's equation will be satisfied for flow across a cross-section.

Which of the above statements is/are correct?

A)

1, 2, 3 and 4

B)

1, 3 and 4

C)

3 and 4

D)

2 only

View Solution

40)

Match List-I (Device) with List-II (Use) and select the correct answer using the codes given below the lists:

List-I (Device)		List-II (Use)
A.	Picot tube	1.	Boundary shear stress
B.	Preston tube	2.	Turbuleny velocity fluctuations
C.	Flow Nozzle	3.	The total head
D.	Hot wire anemometer	4.	Flow rate

Codes:

A)

A\[\to \]4, B\[\to \]2, C\[\to \]3, D\[\to \]1

B)

A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]2

C)

A\[\to \]4, B\[\to \]1, C\[\to \]3, D\[\to \]2

D)

A\[\to \]3, B\[\to \]2, C\[\to \]4, D\[\to \]1

View Solution

41)

Flow separation is caused by:

A)

Thinning of boundary layer thickness to zero

B)

A negative pressure gradient

C)

A positive pressure gradient

D)

Reduction of pressure to local vapour pressure

View Solution

42)

A laminar flow is taking place in a pipe. Match List-I (Term) with List-II (Expression) and select the correct answer using the codes given below the lists:

List-I (Term)		List-II (Expression)
A.	Discharge, Q	1.	\[\frac{16\mu }{\rho \,VD}\]
B.	Pressure drop, \[\frac{\Delta P}{L}\]	2.	\[\frac{\pi \,{{d}^{3}}\Delta p}{128\,\mu L}\]
C.	Friction factor, \[f\]	3.	\[\frac{32\,\mu \,V}{{{D}^{2}}}\]
		4.	\[\frac{\pi {{d}^{4}}\Delta p}{128\,\mu L}\]

Codes:

A)

A\[\to \]2, B\[\to \]3, C\[\to \]4

B)

A\[\to \]4, B\[\to \]3, C\[\to \]1

C)

A\[\to \]4, B\[\to \]1, C\[\to \]3

D)

A\[\to \]1, B\[\to \]4, C\[\to \]2

View Solution

43)

The magnus effect is defined as:

A)

The generation of lift per unit drage force

B)

The circulation induced in an aircraft wing

C)

The separation of boundary layer near the trailing edge of a slender body

D)

The generation of lift on a rotating cylinder in a uniform flow.

View Solution

44)

A \[\frac{1}{25}\] model of a ship is to be tested for estimating the wave drag. If the speed of the ship is 1 m/s, then the speed at which the model must be tested is:

A)

0.04 m/s

B)

0.2 m/s

C)

5.0 m/s

D)

25.0 m/s

View Solution

45)

Consider the following statements for a two- dimensional potential flow:

1. Laplace equation for stream function must be satisfied.

2. Laplace equation for velocity potential must be satisfied.

3. Stremlines and equipotential lines are mutually perpendicular.

4. Streamlines can intersect each other in very high speed flows.

Which of the above statement s are correct?

A)

1 and 4

B)

2 and 4

C)

1, 2 and 3

D)

2, 3 and 4

View Solution

46)

Which of the following equations are forms of continuity equations?

(\[\overrightarrow{V}\]is the velocity and \[\forall \] is volume)

1. \[{{A}_{1}}{{\overrightarrow{V}}_{1}}={{A}_{2}}\overrightarrow{{{V}_{2}}}\]

2. \[1\frac{du}{\partial x}+\frac{dv}{\partial y}=0\]

3. \[\int\limits_{S}{\rho \overrightarrow{V}\,.\,dA+\int\limits_{\forall }{\rho \,d\forall =0}}\]

4. \[\frac{1}{r}\,\,\frac{\partial \,\left( r{{v}_{r}} \right)}{\partial r}+\frac{\partial {{v}_{z}}}{\partial z}=0\]

Select the correct answer using the codes below:

Codes:

A)

1, 2, 3 and 4

B)

1 and 2

C)

3 and 4

D)

2, 3 and 4

View Solution

47)

A solid P floats with half of its volume immersed in water and solid Q floats with two-thirds of the volume immersed in water. The densities of solider P and Q are in ratio:

A)

1 : 2

B)

1 : 3

C)

2 : 3

D)

3 : 4

View Solution

48)

The Bernoulli's equation refers to conservation of:

A)

Mass

B)

linear momentum

C)

Angular momentum

D)

energy

View Solution

49)

The continuity equation in a differential form is:

A)

\[\frac{dA}{A}+\frac{dV}{V}+\frac{dp}{\rho }=\text{constant}\]

B)

\[\frac{A}{dA}+\frac{V}{dV}+\frac{\rho }{dp}=\text{constant}\]

C)

\[\frac{dA}{A}+\frac{dV}{V}+\frac{dp}{\rho }=0\]

D)

\[AdA+VdV+p\,d\rho =0\]

View Solution

50)

Velocity defect in boundary layer theory is defined as:

A)

The error in the measurement of velocity at any point in the boundary layer

B)

The difference between the velocity at a point within the boundary layer and the free stream velocity

C)

The difference between the velocity at any point within the boundary layer and the velocity nearer the boundary

D)

The ratio between the velocity at a point in the boundary layer and the free stream velocity.

View Solution

51)

The drage coefficient for laminar flow varies with Reynolds number (Re) as:

A)

\[{{\operatorname{Re}}^{1/2}}\]

B)

Re

C)

\[{{\operatorname{Re}}^{-1}}\]

D)

\[{{\operatorname{Re}}^{-1/2}}\]

View Solution

52)

Match List-I (Basic Ideal Flow) with List-II (Example) and select the correct answer using the codes given below the lists:

List-I (Basic Ideal Flow)		List-II (Example)
A.	Superposition of a uniform flow over a doublet	1.	Flow over a half Rankine body
B.	Superposition of a uniform flow over a source and sink	2.	Flow over a Rankine oval
C.	Superposition of a uniform flow over a source	3.	Flow over a rotating body
D.	Superposition of a free vortex flow along with a uniform flow over a doublet	4.	Flow over a stationary body

Codes:

A)

A\[\to \]4, B\[\to \]1, C\[\to \]2, D\[\to \]3

B)

A\[\to \]3, B\[\to \]2, C\[\to \]1, D\[\to \]4

C)

A\[\to \]4, B\[\to \]2, C\[\to \]1, D\[\to \]3

D)

A\[\to \]3, B\[\to \]1, C\[\to \]2, D\[\to \]4

View Solution

53)

The square root of the ratio of inertia force to gravity force is called:

A)

Reynolds number

B)

Froude number

C)

Mach number

D)

Euler number

View Solution

54)

The thickness of turbulent boundary layer at a distance x from the leading edge over a flat plate varies as:

A)

\[{{x}^{4/5}}\]

B)

\[{{x}^{1/2}}\]

C)

\[{{x}^{1/5}}\]

D)

\[{{x}^{3/5}}\]

View Solution

55)

For two-dimensionaly fluid element in x-y plane the rotational component is given by:

A)

\[{{\omega }_{z}}=\frac{1}{2}\,\,\left( \frac{\partial u}{\partial x}-\frac{\partial v}{\partial y} \right)\]

B)

\[{{\omega }_{z}}=\frac{1}{2}\,\,\left( \frac{\partial u}{\partial x}+\frac{\partial v}{\partial y} \right)\]

C)

\[{{\omega }_{z}}=\frac{1}{2}\,\,\left( \frac{\partial v}{\partial x}-\frac{\partial u}{\partial y} \right)\]

D)

\[{{\omega }_{z}}=\frac{1}{2}\,\,\left( \frac{\partial v}{\partial x}-\frac{\partial u}{\partial y} \right)\]

View Solution

56)

Which of the following relations must hold for an irrotational two-dimensional flow in the \[x-y\] plane:

A)

\[\frac{\partial v}{\partial y}-\frac{\partial u}{\partial x}=0\]

B)

\[\frac{\partial u}{\partial z}-\frac{\partial v}{\partial x}=0\]

C)

\[\frac{\partial w}{\partial y}-\frac{\partial v}{\partial z}=0\]

D)

\[\frac{\partial v}{\partial x}-\frac{\partial u}{\partial y}=0\]

View Solution

57)

The coefficient of friction \[f\] in terms of shear stress \[{{\tau }_{0}}\] is given by:

A)

\[f=\frac{\rho {{v}^{2}}}{2{{\tau }_{0}}}\]

B)

\[f=\frac{{{\tau }_{0}}}{\rho {{v}^{2}}}\]

C)

\[f=\frac{2{{\tau }_{0}}}{\rho {{v}^{2}}}\]

D)

\[\frac{2\rho {{v}_{0}}}{{{\tau }_{0}}}\]

View Solution

58)

Velocity distribution in a turbulent boundary layer follows:

A)

Logarithmic law

B)

Parabolic law

C)

Linear law

D)

Cubic law

View Solution

59)

What is the discharge for laminar flow through a pipe of diameter 40 mm having centre line velocity of 1.5 m/s?

A)

\[\frac{3\pi }{59}\,{{\text{m}}^{\text{3}}}\text{/s}\]

B)

\[\frac{3\pi }{2,500}\,{{\text{m}}^{\text{3}}}\text{/s}\]

C)

\[\frac{3\pi }{5000}\,{{\text{m}}^{\text{3}}}\text{/s}\]

D)

\[\frac{3\pi }{10000}\,{{\text{m}}^{\text{3}}}\text{/s}\]

View Solution

60)

Which one of the following is the expression for momentum thickness \[\theta \] of a boundary layer?

A)

\[\theta ={{\int\limits_{0}^{\delta }{\left[ 1-\frac{U}{{{U}_{0}}} \right]}}^{2}}\,dy\]

B)

\[\theta ={{\int\limits_{0}^{\delta }{\left[ 1-\frac{U}{{{U}_{0}}} \right]}}^{2}}\,dy\]

C)

\[\theta =\int\limits_{0}^{\delta }{\,\frac{U}{{{U}_{0}}}\left[ 1-\frac{U}{{{U}_{0}}} \right]}\,\,dy\]

D)

\[\theta =\int\limits_{0}^{\delta }{\,\frac{U}{{{U}_{0}}}\left[ 1-\,{{\left( \frac{U}{{{U}_{0}}} \right)}^{2}} \right]}\,\,dy\]

View Solution

61)

The displacement thickness at. Section, for an air stream \[\left( \rho \,\,=\,\,1.2\,\,\text{kg/}{{\text{m}}^{\text{3}}} \right)\] moving with a velocity of 10 m/s over a flat plate is 0.5 mm. What is the loss of mass rate of flow of air due to boundary layer formation in kg per meter width of plate per second?

A)

\[6\times {{10}^{-3}}\]

B)

\[6\times {{10}^{-5}}\]

C)

\[3\times {{10}^{-3}}\]

D)

\[2\times {{10}^{-3}}\]

View Solution

62)

In a laminar boundary layer over a flat plate, what would be the ratio of wall shear stresses \[{{\tau }_{1}}\] and \[{{\tau }_{2}}\] at the two sections which lie at distances \[{{x}_{1}}=30\,\,cm\] and \[{{x}_{2}}=90\,\,cm\] from the leading edge of the plate?

A)

\[\frac{{{\tau }_{1}}}{{{\tau }_{2}}}=3.0\]

B)

\[\frac{{{\tau }_{1}}}{{{\tau }_{2}}}=\frac{1}{3}\]

C)

\[\frac{{{\tau }_{1}}}{{{\tau }_{2}}}=\,\,{{\left( 3.0 \right)}^{1/2}}\]

D)

\[\frac{{{\tau }_{1}}}{{{\tau }_{2}}}=\,\,\left( 3.0 \right)\]

View Solution

63)

Which one of the following is caused by the occurrence of a normal shock in the diverging section of a convergent-divergent nozzle?

Select the correct answer using the codes given below:

A)

1 only

B)

1 and 2

C)

2 and 3

D)

1 and 4

View Solution

64)

A circular plate of 1.5 m diameter is submerged in water with its greatest and least depths below the water surface being 2m and 0.75m respectively. When is the approximate magnitude of the total thrust on one face of the plate?

A)

24 kN

B)

28 kN

C)

12 kN

D)

16 kN

View Solution

65)

Which one of the following statements is correct? A steady flow of diverging straight steam lines:

A)

Is a uniform flow with local acceleration

B)

Has convective normal acceleration

C)

Has convective tangential acceleration

D)

Has both convective normal and tangential accelerations.

View Solution

66)

Which one of the following is the expression of the rotational component for a two-dimensional fluid element in \[x-y\]plane?

A)

\[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial v}{\partial x}-\frac{\partial u}{\partial y} \right)\]

B)

\[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial v}{\partial x}-\frac{\partial u}{\partial y} \right)\]

C)

\[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial v}{\partial x}-\frac{\partial v}{\partial y} \right)\]

D)

\[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial u}{\partial x}+\frac{\partial v}{\partial y} \right)\]

View Solution

67)

What is the percentage error in the estimation of the discharge due to an error of 2% in the measurement of the reading of a differential manometer connected to an orifice meter?

A)

4

B)

3

C)

2

D)

1

View Solution

68)

Which one of the following is the characteristics a fully developed laminar:

A)

The pressure drop in the flow direction is zero

B)

The velocity profile changes uniformly in the flow direction

C)

The velocity profile does not change in the flow direction

D)

The Reynolds number for the flow is critical.

View Solution

69)

Which one of the following is the correct relationship between the boundary layer thickness \[\delta ,\] displacement thickness \[\delta *\] and the momentum thickness \[\theta ?\]

A)

\[\delta <\delta *>\theta \]

B)

\[\delta *>\theta >\delta \]

C)

\[\theta >\delta >\delta *\]

D)

\[\theta >\delta *>\delta \]

View Solution

70)

The thickness of turbulent boundary layer at a distance x from the leading edge on a flat plate varies as:

A)

\[{{x}^{4/5}}\]

B)

\[{{x}^{3/5}}\]

C)

\[{{x}^{1/2}}\]

D)

\[{{x}^{1/5}}\]

View Solution

71)

When a fait plate of \[0.1\,{{m}^{2}}\] area is pulled at a constant velocity of 30 cm/s parallel to another stationary plate pocaled at a distance 0.01 cm from it and the space in between filled with a fluid of dynamic viscosity \[=\,\,0.01\,\,\text{Ns/}{{\text{m}}^{\text{2,}}}\] the force required to be applied is

A)

0.3 N

B)

3 N

C)

10 N

D)

16 N

View Solution

72)

Which one of the following is the continuity equation in differential form? (The symbols have usual meanings)

A)

\[\frac{dA}{A}+\frac{dV}{V}+\frac{d\rho }{\rho }=\text{constant}\]

B)

\[\frac{dA}{A}+\frac{dV}{V}+\frac{d\rho }{\rho }=0\]

C)

\[\frac{A}{dA}+\frac{V}{dV}+\frac{\rho }{d\rho }=\text{constant}\]

D)

\[AdA+VdA+\rho d\rho =0\]

View Solution

73)

What will be the maximum efficiency of the pipeline if one-third of the available head in flow through the pipeline is consumed by friction?

A)

33.33%

B)

50.00%

C)

66.66%

D)

75.00%

View Solution

74)

Which one of the following is satisfied if the flow is irrotational for a two-dimensional fluid element in the \[x-y\] plane?

A)

\[\frac{\partial v}{\partial x}=\frac{\partial u}{\partial y}\]

B)

\[\frac{\partial v}{\partial x}=\frac{\partial u}{\partial y}\]

C)

\[\frac{\partial u}{\partial x}=\frac{\partial v}{\partial y}\]

D)

\[\frac{\partial u}{\partial x}=\frac{\partial v}{\partial y}\]

View Solution

75)

The velocity distributions in laminar boundary layer is given by the relation \[u/{{u}_{\infty }}=\,y/\delta .\] what is the momentum thickness for the boundary layer?

A)

\[\delta /2\]

B)

\[\delta /3\]

C)

\[\delta /4\]

D)

\[\delta /6\]

View Solution

76)

How the Von-Karman momentum integral equation expressed is (\[\theta \] is momentum thickness)?

A)

\[\frac{{{\tau }_{0}}}{\frac{1}{2}\,\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\]

B)

\[\frac{{{\tau }_{0}}}{2\,\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\]

C)

\[\frac{{{\tau }_{0}}}{\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\]

D)

\[\frac{{{\tau }_{0}}}{\frac{1}{3}\,\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\]

View Solution

77)

Air (kinematic viscosity \[=15\times {{10}^{-6}}{{\text{m}}^{\text{2}}}\text{/s}\]) with a free stream velocity of 10 m/s flows over a smooth two- dimensional flat plate. If the critical Reynolds number is \[5\times 10,\] what is the maximum distance from the leading edge up to which laminar boundary layer exists?

A)

30 cm

B)

75 cm

C)

150 cm

D)

300 cm

View Solution

78)

Using the Prandtl's mixing length concept, how is the turbulent shear stress expressed?

A)

\[\rho l\,\overline{\frac{du}{dy}}\]

B)

\[\rho {{l}^{2}}\,\overline{\frac{du}{dy}}\]

C)

\[\rho l\,{{\left( \overline{\frac{du}{dy}} \right)}^{2}}\]

D)

\[\rho {{l}^{2}}\,{{\left( \overline{\frac{du}{dy}} \right)}^{2}}\]

View Solution

79)

Consider the following statements:

The state of stress in a fluid consists of normal pressure only if the fluid:

1. is at rest

2. Is in uniform motion

3. Has non-uniform velocity profile

4. Has zero viscosity.

Which of the statements given above are correct?

A)

1, 2 and 3

B)

1, 2 and 4

C)

1, 3 and 4

D)

2, 3 and 4

View Solution

80)

Darcy-Weisback equation for the head loss in a flow through a pipe is given by \[{{h}_{1}}=4\,fl{{v}^{2}}\] (2gd) (the symbols have the usual meaning). For the laminar flow through a circular pipe, how does the friction factor \[f\] vary with the Reynolds number (Re):

A)

\[f=\text{8/Re}\]

B)

\[f=16\text{/Re}\]

C)

\[f=32\text{/Re}\]

D)

\[f=64\text{/Re}\]

View Solution

81)

The velocity distribution in laminar boundary layer is given by the relation \[u/{{u}_{x}}=y/\delta .\] What is the displacement thickness for the boundary layer?

A)

\[\delta \]

B)

\[\delta /2\]

C)

\[\delta /3\]

D)

\[\delta /4\]

View Solution

82)

Which one of the following equations gives the velocity distribution across a circular pipe having a viscous flow?

A)

\[u={{u}_{\max }}\,[1-{{(r/R)}^{2}}]\]

B)

\[u={{u}_{\max }}\,[{{R}^{2}}-{{r}^{2}}]\]

C)

\[u={{u}_{\max }}\,{{[1-(r/R)]}^{2}}\]

D)

\[u={{u}_{\max }}\,{{[1+(r/R)]}^{2}}\]

View Solution

83)

In a two-dimensional fluid flow,\[u=6x+xy.\] which one of the following gives the component of the velocity to satisfy the continuity equation?

A)

\[6x+xy\]

B)

\[6+xy\]

C)

\[-\,\left( 6x+xy \right)\]

D)

\[-\,\left( 6y+\frac{1}{2}\,{{y}^{2}} \right)\]

View Solution

84)

If \[u=ax\] and \[v=-\,ay\] give the velocity distribution for a two-dimensional flow, what is the equation of a stream line passing through the point (3, 1)?

A)

\[xy=3\]

B)

\[x+y=4\]

C)

\[x+3y=6\]

D)

\[{{x}^{2}}y=9\]

View Solution

85)

Consider the following statements:

1. Boundary-layer thickness in laminar flow is greater than that of turbulent flow.

2. Boundary-layer thickness of turbulent flow is greater than that of laminar flow.

3. Velocity distributes uniformly in a turbulent boundary-layer.

4. Velocity has a gradual variation in a laminar boundary layer.

Which of the statements given above are correct?

A)

1, 3 and 4 only

B)

1, 2, 3 and 4

C)

1 and 2 only

D)

2, 3 and 4, only

View Solution

86)

Motion economy is better achieved by

A)

Method study

B)

Time study

C)

Work space design

D)

Process planning.

View Solution

87)

Which one of the following is the correct statement? The velocity profiles for fully developed laminar and turbulent flow, respectively, in a pipe are:

A)

Parabolic and parabolic

B)

Parabolic and elliptic

C)

Linear and 1/7 power law

D)

Parabolic and 1/7 power law

View Solution

88)

Which one of the following is the correct statement? For the case of laminar flow between two fixed parallel plates, the shear stress is

A)

Constant across the passage

B)

Maximum at the Centre and zero at the boundary

C)

Zero all through the passage

D)

Maximum at the boundary and zero at the centre

View Solution

89)

Consider the following statements:

The coefficient of discharge \[{{C}_{d}}\] of a venturimeter takes into account.

1. The effect of roughness of the surface

2. Non-uniform velocity distributions at inlet and throat section.

3. Reynolds number of flow

4. Discharge

5. Length of throat

6. Diameter of throat

7. Diameter ratio

Which of the statements given above are correct?

A)

1, 2, 4 and 5

B)

1, 4, 5 and 6

C)

1, 2, 3 and 7

D)

2, 6 and 7

View Solution

90)

Which one of the following expresses the error in discharge due to error in the measurement of head over a triangular notch?

A)

\[\frac{dQ}{Q}=\frac{5dH}{2H}\]

B)

\[\frac{dQ}{Q}=\frac{3dH}{2H}\]

C)

\[\frac{dQ}{Q}=\frac{7dH}{2H}\]

D)

\[\frac{dQ}{Q}=\frac{1dH}{2H}\]

View Solution

91)

Which one of the following is the correct statement? A differential manometer connected to a pitotstatic tube used for measuring fluid velocity gives:

A)

Static pressure

B)

Total pressure

C)

Dynamic pressure

D)

Difference between total pressure and dynamic pressure.

View Solution

92)

Which one of the following correctly represents the shear stress distribution across a section of a circular pipe having a viscous flow?

A)

\[\tau =\frac{\partial p{{r}^{2}}}{\partial x}\]

B)

\[\tau =\frac{\partial p\left( r/2 \right)}{\partial x}\]

C)

\[\tau =-\,\,\frac{\partial p\left( r/2 \right)}{\partial x}\]

D)

\[\tau =\frac{\partial p\left( r \right)}{\partial x}\]

View Solution

93)

A pipe of diameter D conveying a discharge Q is to be replaced by parallel pipes of smaller diameter d to discharge the same quantity. What will be the ratio of \[\frac{D}{d}\,?\](\[f\]Is same for all pipes)

A)

\[\frac{D}{d}=2\]

B)

\[\frac{D}{d}=\sqrt{2}\]

C)

\[\frac{D}{d}={{4}^{1/5}}\]

D)

\[\frac{D}{d}={{4}^{1/3}}\]

View Solution

94)

Match List-I (Forms of Bernouli'sEquation ) with List-II (Units of these forms) and select the correct answer using codes given below the lists:

List-I (from of Bernouli?s Equation)		List-II (Units of these forms)
A.	\[p+wz+\frac{\rho {{V}^{2}}}{2}\]	1.	Total energy per unit volume
B.	\[\frac{p}{\acute{A}}+gz+\frac{{{V}^{2}}}{2}\]	2.	Total energy per unit mass
C.	\[\frac{p}{w}+z+\frac{{{V}^{2}}}{2g}\]	3.	Total energy per unit weight

Codes:

A)

A\[\to \]1, B\[\to \]2, C\[\to \]3

B)

A\[\to \]1, B\[\to \]3, C\[\to \]2

C)

A\[\to \]2, B\[\to \]1, C\[\to \]3

D)

A\[\to \]2, B\[\to \]3, C\[\to \]1

View Solution

95)

Which one of the following is the correct statement? A frictionless, incompressible fluid flows steadily through a convergent nozzle, then its.

A)

Energy must decrease

B)

Velocity must decrease

C)

Pressure must decrease

D)

Momentum must decrease

View Solution

96)

Which one of the following statements is correct stability of a floating body:

A)

M should lie between G and B (in that order)

B)

M should lie above B and G (in that order)

C)

M should lie below B and G (in that order)

D)

M should coincide with B and G

View Solution

97)

Consider the following statements:

A rectangular block of wood of size \[L\times B\times H\]float in water in such a way that:

(1) The longest dimension is vertical

(2) The longest dimension is horizontal

(3) The metacentre is above Centre of gravity

(4) The Centre of buoyancy is above the Centre of gravity

Which of the statements given above is/are correct?

A)

1 only

B)

2 only 3, only

C)

2, 3 and 4

D)

1, 3 and 4

View Solution

98)

Bernoulli's equation is derived by making which one of the following assumptions?

A)

The flow is steady only

B)

The flow is uniform and incompressible

C)

The flow is non-viscous, uniform and steady

D)

The flow is steady, non-viscous, incompressible and irrotational.

View Solution

99)

A skater weighing 1000 N skates at a speed of 20 m/s on ice maintained at \[0{}^\circ C.\] the average skating area supporting the skater is \[0.001\,{{m}^{2}}\] and the coefficient of friction between the skatesandice is 0.02. What will be the average thickness of a film of water existing at the interface between the skater and ice? (Take dynamic viscosity of water as \[0.001\,\text{Ns/}{{\text{m}}^{\text{2}}}\])

A)

\[{{10}^{-5m}}\]

B)

\[{{10}^{-6}}\]

C)

\[{{10}^{-2}}\]

D)

Not possible to estimate since there cannot be a possibility, of formation of a thin film of water at interface

View Solution

100)

Flow separation is likely to take place when the pressure gradient in the direction of flow is:

A)

Zero

B)

Adverse

C)

Slightly favourable

D)

Strongly favourable

View Solution

101)

The vertical component of the hydrostatic force on a submerged curved surface is the:

A)

Mass of liquid vertically above it

B)

Weight of the liquid vertically above it

C)

Force on a vertical projection of the surface

D)

Product of pressure at the centroid and the surface area

View Solution

102)

If a hydraulic press has a ram of 12.5 cm diameter and plunger of 1.25 cm diameter, what force would be required on the plunger to raise a mass of 1 tonne on the ram?

A)

981 N

B)

98.1 N

C)

9.81 N

D)

0.98 N

View Solution

103)

A liquid mass readjusts itself and undergoes a rigid body type of motion when it is subjected to a:

A)

Constant angular velocity

B)

Constant angular acceleration

C)

Linearly varying velocity

D)

Linearly varying acceleration

View Solution

104)

In a two-dimensional flow, where u is the x-component and v is the y-component of velocity, the equation of streamline is given by:

A)

\[udx-vdy=0\]

B)

\[vdx-udy=0\]

C)

\[uv\,dx-dy=0\]

D)

\[udx+vdy=0\]

View Solution

105)

The continuity equation \[\frac{\partial u}{\partial x}+\frac{\partial v}{\partial y}+\frac{\partial w}{\partial z}=0\] is valid only for:

A)

Ideal fluid flow

B)

Incompressible fluid whether the flow is steady or not

C)

Steady flow, whether is compressible or not

D)

Steady flow and compressible fluids

View Solution

106)

From a reservoir, water is drained through two pipes of 10 cm and 20 cm diameter respectively. If the frictional head loss in both the pipes is same, then the ratio of discharge through the larger pipe to that through the smaller pipe will be:

A)

\[\sqrt{2}\]

B)

\[2\sqrt{2}\]

C)

4

D)

\[4\sqrt{2}\]

View Solution

107)

While water passes through a given pipe at a mean velocity 'V, the flow is found to change from laminar to turbulent. If another fluid of specific gravity 0.8 and coefficient of viscosity 20% of that of water, is passed through the same pipe, the transition of flow from laminar to turbulent is expected if the flow velocity is:

A)

2V

B)

V

C)

V/2

D)

V/4

View Solution

108)

A hydraulic jump is formed in a 5.0 wide rectangular channel with sequent depths of 0.2 m and 0.8 m. The discharge in the channel, in \[{{\text{m}}^{\text{3}}}\text{/s,}\] is:

A)

2.43

B)

3.45

C)

4.43

D)

5.00

View Solution

109)

If the velocity distribution in a turbulent boundary layer is given by \[\frac{u}{{{u}_{\infty }}}={{\left( \frac{y}{\delta } \right)}^{1/9}}\] then the ratio of displacement thickness to nominal boundary layer thickness will be:

A)

1.0

B)

0.6

C)

0.3

D)

0.1

View Solution

110)

The barometric pressure at the base of mountain is 750 mm Hg and at the top 600 mm Hg. If the average air density is \[1\,\,\text{kg/}{{\text{m}}^{\text{3}}}\text{,}\] the height of the mountain is approximately:

A)

2000 m

B)

3000 m

C)

4000 m

D)

5000 m

View Solution

111)

At the interface of a liquid and a gas at rest, the pressure is:

A)

Higher on the concave side compared to that on the convex side

B)

Higher on the convex side compared to that on the concave side

C)

Equal on both sides

D)

Equal to surface tension divided by radius of curvature on both sides

View Solution

112)

A rectangular tank of base size \[3\,m\,\,\times \,\,3\,m\] contains oil of specific gravity 0.8 upto a height of 8 m. When it is accelerated at \[2.45\,\text{m/}{{\text{s}}^{\text{2}}}\] vertically upwards, the force on the base of the tank will be:

A)

29400 N

B)

38240 N

C)

78400 N

D)

49050 N

View Solution

113)

Match List-I with List-II and select the correct answer using the codes given below the lists:

List-I (Device)		List-II (Use)
A.	Barometer	1.	Gauge pressure
B.	Hydrometer	2.	Local atmospheric pressure
C.	U-tube manometer	3.	Relative density
D.	Bourden gauge	4.	Pressure differential

Codes: