Fluid Mechanics Reference Guide

Properties of Fluids

A substance which deforms continuously under the action of shear stress is called
a) liquid
b) gas
c) fluid
d) solid

Practical fluids possess
a) viscosity
b) surface tension
c) compressibility
d) all of the above

An ideal fluid is
a) frictionless and incompressible
b) obeys Newton's law of viscosity
c) is similar to gas
d) is very viscous

Variation in volume of liquid with variation in pressure is called
a) plasticity
b) viscosity
c) compressibility
d) none of the above

Poise is the unit of
a) mass density
b) kinematic viscosity
c) viscosity
d) none of the above

Stoke is the unit of
a) surface tension
b) pressure gradient
c) kinematic viscosity
d) none of the above

If the volume of a liquid weighing 3 kg is 4 m³, then 0.75 is its
a) specific weight
b) mass
c) specific gravity
d) none of these

Water belongs to
a) Newtonian fluids
b) non-Newtonian fluids
c) compressible fluids
d) none of these

Hooke's law for solid is analogous to
a) Newton's law of viscosity
b) Pascal's law
c) Boundary layer theory
d) Continuity equation

The viscosity of liquid varies with temperature
a) directly proportional
b) inversely proportional
c) decreases with temperature
d) none of the above

The viscosity of gases varies with temperature
a) directly proportional
b) inversely proportional
c) constant
d) none of the above

Surface tension is the force
a) per unit length
b) per unit area
c) per unit volume
d) all of the above

Falling drops of water become spheres due to
a) adhesion
b) cohesion
c) surface tension
d) viscosity

The pressure difference inside and outside a droplet of water is given by
a) ΔP = σ/r
b) ΔP = 2σ/r
c) ΔP = 4σ/r
d) ΔP = σ/2r

The phenomenon of rising of a liquid surface in a tube of small diameter relative to the adjacent normal level of the liquid is known as
a) capillary rise
b) capillary fall
c) rising
d) none of the above

Capillary rise is proportional to
a) surface tension
b) unit weight of water
c) diameter of pipe
d) none of the above

The capillary rise or fall of liquid is given by
a) 80cosθ/d
b) 40cosθ/d
c) 4σcosθ/ρgd
d) none of the above

Cavitation is caused by
a) Low pressure
b) High pressure
c) Low velocity
d) High velocity

Cavitation is collapsed by
a) Low pressure
b) High pressure
c) Low velocity
d) High velocity

The property making liquids oppose relative motion between layers is:
a) Surface tension
b) Coefficient of viscosity
c) Viscosity
d) Osmosis

Weight per unit volume at STP is:
a) Specific weight (γ)
b) Mass density (ρ)
c) Specific gravity (SG)
d) None

Viscosity affects flow rate:
a) Effects
b) No effect
c) Both
d) None

Newtonian stress-strain is:
a) Linear (τ = μ(du/dy))
b) Parabolic
c) Hyperbolic
d) Inverse

Oil with γ=7.85 kN/m³ has SG:
a) 0.8
b) 1.0
c) 1.2
d) 1.6

Bulk modulus shows volume:
a) Constant
b) Decreases
c) Increases
d) None

Given V₁=0.04m³@50kg/cm², V₂=0.039m³@150kg/cm², bulk modulus is:
a) 400 kg/cm²
b) 4000 kg/cm²
c) 40×10⁵ kg/cm²
d) 40×10⁶ kg/cm²

Fluids in equilibrium cannot sustain:
a) Tensile stress
b) Compressive stress
c) Shear stress
d) Bending stress

Property resisting tensile stress:
a) Compressibility
b) Surface tension
c) Cohesion
d) Adhesion

Vapor pressure over a concave surface is:
a) Less than over plane surface
b) Equal to plane surface
c) Greater than plane surface
d) Zero

When pressure increases, fluid density:
a) Decreases
b) Increases
c) Remains same
d) May increase/decrease

Condition for liquid boiling:
a) Pabs ≥ Pvapor
b) Pabs ≤ Pvapor
c) Pabs = Pvapor
d) Pabs ≤ Pvapor

Ideal flow obeys:
a) Continuity equation (A₁V₁ = A₂V₂)
b) Newton's viscosity law
c) Newton's 2nd law
d) Dynamic viscosity

Gas viscosity arises from:
a) Cohesion (liquid property)
b) Temperature
c) Molecular momentum transfer
d) None

A fluid which obeys the Newton's law of viscosity is termed as
a) Real fluid
b) Ideal fluid
c) Newtonian fluid
d) Non-Newtonian fluid

The property of fluid by virtue of which it offers resistance to shear is called
a) Surface tension
b) Adhesion
c) Cohesion
d) Viscosity

Practical fluids
a) Are viscous
b) Possess surface tension
c) Are compressible
d) All of the above

Fluid is a substance that
a) Cannot be subjected to shear forces
b) Always expands until it fills any container
c) Cannot remain at rest under action of any shear force
d) None of these

Dimensions of surface tension are
a) MT⁻²
b) ML°T
c) ML r²
d) ML²T²

The tendency of a liquid surface to contract is due to the following property
a) Cohesion
b) Adhesion
c) Viscosity
d) Surface tension

The property of a fluid which enables it to resist tensile stress is known as
a) Compressibility
b) Surface tension
c) Cohesion
d) Adhesion

Dynamic viscosity of most of the gases with rise in temperature
a) Increases
b) Decreases
c) Remain unaffected
d) Unpredictable

Stoke is the unit of
a) Kinematic viscosity in C.G.S. units
b) Kinematic viscosity in M.K.S. units
c) Dynamic viscosity in M.K.S. units
d) Dynamic viscosity in S.I. units

The unit of viscosity is
a) Metres² per sec
b) kg-sec/metre
c) Newton-sec per metre²
d) Newton-sec per meter

The viscosity of water at 20°C is
a) One stoke
b) One centistoke
c) One poise
d) One centipoise

The unit of dynamic viscosity in S.I. units is
a) N-m/s²
b) N-s/m²
c) Poise
d) Stoke

The ratio of absolute viscosity to mass density is known as
a) Specific viscosity
b) Viscosity index
c) Kinematic viscosity
d) Coefficient of viscosity

Unit of surface tension is
a) Energy/unit area
b) Velocity/unit area
c) Both of the above
d) It has no units

Capillary action is due to the
a) Surface tension
b) Cohesion of the liquid
c) Adhesion of the liquid molecules and the molecules on the surface of a solid
d) All of the above

Free surface of a liquid behaves like a sheet and tends to contract to smallest possible area due to the
a) Force of adhesion
b) Force of cohesion
c) Force of friction
d) Force of diffusion

Choose the wrong statement
a) Viscosity of a fluid is that property which determines the amount of its resistance to a shearing force
b) Viscosity is due primarily to interaction between fluid molecules
c) Viscosity of liquids decreases with increase in temperature
d) Viscosity of liquids is appreciably affected by change in pressure

A perfect gas
a) Has constant viscosity
b) Has zero viscosity
c) Is incompressible
d) None of the above

Fluid Statics

Pascal's law states that pressure at a point is equal in all directions
a) in a liquid at rest
b) in a fluid at rest
c) in a laminar flow
d) in a turbulent flow

To measure atmospheric pressure, we use
a) Barometer
b) Piezometer
c) Manometers
d) Differential manometers

The pressure less than atmospheric pressure is known as
a) suction pressure
b) vacuum pressure
c) negative pressure
d) all of the above

The atmospheric pressure varies with
a) altitude
b) temperature
c) weather conditions
d) all of the above

Differential manometers are used to measure
a) pressure in water channels, etc
b) difference in pressure at two points
c) atmospheric pressure
d) very low pressure

Piezometers are used to measure
a) pressure in water channels, etc
b) difference in pressure at two points
c) atmospheric pressure
d) very low pressure

The pressure in pipe flow is normally
a) less than atmospheric pressure
b) equal to atmospheric pressure
c) more than atmospheric pressure
d) none of the above

1 m head is equivalent to
a) 0.1 kg/cm²
b) 0.2 kg/cm²
c) 0.3 kg/cm²
d) 0.4 kg/cm²

An oil of specific gravity 0.7 and pressure 0.14 kgf/cm² will have the height of oil as
a) 70 cm of oil
b) 2m of oil
c) 20 cm of oil
d) 80 cm of oil

When a body is placed over a liquid, it will sink down if:
a) Gravitational force equals the up-thrust
b) Gravitational force is less than up-thrust
c) Gravitational force exceeds up-thrust
d) None of these

A floating body oscillates about:
a) C.G.
b) Pressure center
c) Buoyancy center
d) Metacentre

Body returning to original position when tilted is:
a) Neutral
b) Stable (M above G)
c) Unstable
d) None

When a liquid-filled cylinder rotates, the surface becomes:
a) Triangular
b) Paraboloid
c) Elliptical
d) None

When a tank accelerates horizontally, the liquid surface:
a) Stays horizontal
b) Tilts (falls at front, rises at back)
c) Falls only at front
d) Falls only at back

For SG_metal=7 in SG_Hg=13.6, submerged fraction is:
a) 0.5
b) 0.4
c) 0.515
d) 0.6

Ideal manometer liquid has:
a) High surface tension
b) Low surface tension
c) Irrelevant surface tension
d) High density/viscosity

Inclined vs U-tube sensitivity ratio:
a) sinθ
b) 1/sinθ
c) cosθ
d) 1/cosθ

When a body is placed over a liquid, it will sink down if
a) Gravitational force is equal to the up-thrust of the liquid
b) Gravitational force is less than the up-thrust of the liquid
c) Gravitational force is more than the up-thrust of the liquid
d) None of the above

In an immersed body, centre of pressure is
a) At the centre of gravity
b) Above the centre of gravity
c) Below the centre of gravity
d) Could be above or below e.g. depending on density of body and liquid

The resultant upward pressure of the fluid on an immersed body is called
a) Up-thrust
b) Buoyancy
c) Center of pressure
d) All the above are correct

Center of buoyancy is the
a) Centroid of the displaced volume of fluid
b) Center of pressure of displaced volume
c) Does not exist
d) None of the above

When a body floating in a liquid is displaced slightly, it oscillates about
a) C.G. of body
b) Center of pressure
c) Center of buoyancy
d) Metacentre

For a body floating in a liquid the normal pressure exerted by the liquid acts at
a) Bottom of the body
b) C.G. of the body
c) Metacentre
d) All points on the surface of the body

A piece of metal of specific gravity 7 floats in mercury of specific gravity 13.6. What fraction of its volume is under mercury?
a) 0.5
b) 0.4
c) 0.515
d) 0.5

When a cylindrical vessel containing liquid is resolved, the surface of the liquid takes the shape of
a) A triangle
b) A paraboloid
c) An ellipse
d) None of these

A pressure of 25 m of head of water is equal to
a) 25 kN/m²
b) 245 kN/m²
c) 2500 kN/m²
d) 2.5 kN/m²

The point in the immersed body through which the resultant pressure of the liquid may be taken to act is known as
a) Meta center
b) Center of pressure
c) Center of buoyancy
d) Center of gravity

Center of pressure compared to e.g. is
a) Above it
b) Below it
c) At same point
d) Above or below depending on area of body

The centre of gravity of the volume of the liquid displaced by an immersed body is called
a) Centre of gravity
b) Centre of pressure
c) Metacentre
d) Centre of buoyancy

According to the principle of buoyancy a body totally or partially immersed in a fluid will be lifted up by a force equal to
a) The weight of the body
b) More than the weight of the body
c) Less than the weight of the body
d) Weight of the fluid displaced by the body

The pressure measured with the help of a pressure gauge is called
a) Atmospheric pressure
b) Gauge pressure
c) Absolute pressure
d) Mean pressure

The absolute pressure is equal to
a) Gauge pressure + atmospheric pressure
b) Gauge pressure - atmospheric pressure
c) Atmospheric pressure - gauge pressure
d) Gauge pressure - vacuum pressure

The intensity of pressure on an immersed surface __________ with the increase in depth.
a) Does not change
b) Increases
c) Decreases
d) None of these

Buoyant force is
a) The resultant force acting on a floating body
b) The resultant force on a body due to the fluid surrounding it
c) Equal to the volume of liquid displaced
d) The force necessary to maintain equilibrium of a submerged body

Metacentric height is given as the distance between
a) The center of gravity of the body and the metacentre
b) The center of gravity of the body and the center of buoyancy
c) The center of gravity of the body and the center of pressure
d) Center of buoyancy and metacentre

The most economical section of a rectangular channel is one which has hydraulic mean depth or hydraulic radius equal to
a) Half the depth
b) Half the breadth
c) Twice the depth
d) Twice the breadth

The most economical section of a trapezoidal channel is one which has hydraulic mean depth equal to
a) 1/2 × depth
b) 1/2 × breadth
c) 1/2 × sloping side
d) 1/4 × (depth + breadth)

A bucket of water is hanging from a spring balance. An iron piece is suspended into water without touching sides of bucket from another support. The spring balance reading will
a) Increase
b) Decrease
c) Remain same
d) Increase/decrease depending on depth of immersion

A balloon lifting in air follows the following principle
a) Law of gravitation
b) Archimedes principle
c) Principle of buoyancy
d) All of the above

One litre of water occupies a volume of
a) 1000 cm³
b) 250 cm³
c) 500 cm³
d) 100 cm³

The volume of a fluid __________ as the pressure increases.
a) Remains same
b) Decreases
c) Increases
d) None of these

The capillary rise at 20°C in a clean glass tube of 1 mm bore containing water is approximately
a) 5 mm
b) 10 mm
c) 20 mm
d) 30 mm

Surface tension has the units of
a) Newton-sec/m
b) Newton/m²
c) Newton/m
d) Newton

Fluid is a substance which offers no resistance to change of
a) Pressure
b) Flow
c) Shape
d) Volume

A fluid is said to be ideal, if it is
a) Incompressible
b) Viscous and incompressible
c) Inviscous and compressible
d) Inviscous and incompressible

Choose the wrong statement
a) The center of buoyancy is located at the center of gravity of the displaced liquid
b) For stability of a submerged body, the center of gravity of body must lie directly below the center of buoyancy
c) If C.G. and center of buoyancy coincide, the submerged body must lie at neutral equilibrium for all positions
d) All floating bodies are stable

Surface tension has the units of
a) Newton-sec/m
b) Newton/m²
c) Newton/m
d) Newton

Fluid is a substance which offers no resistance to change of
a) Pressure
b) Flow
c) Shape
d) Volume

The kinematic viscosity is the
a) Ratio of absolute viscosity to the density of the liquid
b) Ratio of density of the liquid to the absolute viscosity
c) Product of absolute viscosity and density of the liquid
d) Product of absolute viscosity and mass of the liquid

Choose the correct relationship
a) Specific gravity = gravity × density
b) Dynamic viscosity = kinematic viscosity × density
c) Gravity = specific gravity × density
d) Kinematic viscosity = dynamic viscosity × density

Surface energy per unit area of a surface is numerically equal to
a) Atmospheric pressure
b) Surface tension
c) Force of adhesion
d) Force of cohesion

The viscosity of water is __________ than that of mercury.
a) Higher
b) Lower
c) Same as
d) None of these

The intensity of pressure at any point, in a liquid, is __________ to the depth of liquid from the surface.
a) Equal
b) Directly proportional
c) Inversely proportional
d) None of these

The center of gravity of the volume of the liquid displaced by an immersed body is called
a) Metacentre
b) Center of pressure
c) Center of buoyancy
d) Center of gravity

The pressure less than atmospheric pressure is known as
a) Suction pressure
b) Vacuum pressure
c) Negative gauge pressure
d) All of these

The normal stress in a fluid will be constant in all directions at a point only if
a) It is incompressible
b) It has uniform viscosity
c) It has zero viscosity
d) It is at rest

Metacentric height is the distance between the metacentre and
a) Water surface
b) Center of pressure
c) Center of gravity
d) Center of buoyancy

In immersed bodies, center of pressure is:
a) At C.G.
b) Above C.G.
c) Below C.G.
d) Variable

Fluid Kinematics

The imaginary line drawn such that the tangents at its all points indicates the direction of the velocity of the fluid particles at each point, is called
a) path line
b) stream line
c) potential line
d) streak line

In fluids, steady flow occurs when
a) condition of flow changes steadily with time
b) condition of flow not change with time
c) condition of flow remains the same at the adjacent point
d) velocity vector remains constant at a point

Uniform flow is said to occur when
a) size and shape of the cross-section in a particular length remain constant
b) size and shape of the cross-section change along length
c) friction loss in the particular length of the channel will be more than the drop in elevation
d) frictional loss in the particular length of the channel will be less than the drop in elevation

If the velocity, pressure, density, etc., do not change at a point with respect to time, the flow is called
a) uniform
b) incompressible
c) nonuniform
d) steady

If the velocity, pressure, density, etc., change at a point with respect to time, the flow is called
a) uniform
b) compressible
c) unsteady
d) incompressible

If the velocity in a fluid flow does not change with respect to the length of direction flow, it is called
a) steady flow
b) uniform flow
c) incompressible flow
d) rotational flow

If the velocity in a fluid flow changes with respect to the length of direction flow, it is called
a) unsteady flow
b) compressible flow
c) rotational flow
d) none of the above

If the density of a fluid is constant from point to point in a flow region, it is called
a) steady flow
b) incompressible flow
c) uniform flow
d) rotational flow

If the density of a fluid changes from point to point in a flow region, it is called
a) steady flow
b) incompressible flow
c) non-uniform flow
d) compressible flow

If the velocity of fluid particles varies from point to point in magnitude and direction, as well as from instant to instant, the flow is said to be
a) laminar
b) turbulent flow
c) uniform flow
d) non-uniform flow

The flow in which path of individual fluid particles of liquid cross each other is called
a) uniform flow
b) turbulent flow
c) stream line flow
d) none of the above

A steady uniform flow is through a
a) long pipe at decreasing rate
b) long pipe at constant rate
c) long pipe at increasing rate
d) none of the above

A flow whose streamline is represented by a curve is called:
a) One-dimensional flow
b) Two-dimensional flow
c) Three-dimensional flow
d) Four-dimensional flow

The path traced by a single particle of smoke issuing from a cigarette is a
a) Streamline
b) Flow line
c) Path line
d) Streakline

Laminar flow is also called
a) Steady flow
b) Uniform flow
c) Unsteady flow
d) Streamline or viscous flow

A streamline is a line
a) Connecting mid points of a flow cross-section
b) Drawn normal to the velocity vector at any point
c) Connecting points of equal velocity in a flow
d) Tangent to which at any point gives the direction of velocity

For a two-dimensional flow field, the equation of streamline is
a) u dy = v dx
b) du/dy = dv/dx
c) dx/u = dy/v
d) dy/dx = v/u

Steady irrotational flow of an incompressible fluid is called
a) Streamline flow
b) Potential flow
c) Shear flow
d) Creeping flow

During the opening of a valve, the flow is
a) Laminar
b) Unsteady
c) Uniform
d) Rotational

If ψ is the stream function, then velocity components u and v are given by:
a) u = ∂ψ/∂y, v = ∂ψ/∂x
b) u = ∂ψ/∂x, v = ∂ψ/∂y
c) u = -∂ψ/∂y, v = ∂ψ/∂x
d) u = ∂ψ/∂x, v = -∂ψ/∂y

The continuity equation ∇·V = 0 is valid for
a) ideal fluid flow only
b) incompressible fluids, whether flow is steady or unsteady
c) steady flow, whether compressible or incompressible flow
d) incompressible fluids and steady flow only

Flow of water in river is example of
a) One dimensional flow
b) Laminar flow
c) Two dimensional flow
d) Three dimensional flow

If φ is a potential function, then velocity components u and v are given by
a) u = -∂φ/∂x, v = -∂φ/∂y
b) u = ∂φ/∂x, v = ∂φ/∂y
c) u = ∂φ/∂y, v = ∂φ/∂x
d) u = -∂φ/∂y, v = -∂φ/∂x

Vorticity is given by
a) 1.5 times rotation
b) Two times rotation
c) Three times rotation
d) equal to rotation

The local acceleration in the direction of x is given by
a) ∂u/∂x
b) ∂u/∂t
c) Du/Dt
d) None of these

If velocity in a fluid flow does not change with respect to length of direction of flow, it is called
a) Uniform flow
b) Steady flow
c) Incompressible flow
d) Rotational flow

If density of fluid is constant from point to point in a flow region, it is called
a) Unsteady flow
b) Irrotational flow
c) Incompressible flow
d) none of the above

If the velocity, pressure, density etc. do not change at a point with respect to time, the flow is called
a) Uniform
b) Steady
c) Non-uniform
d) incompressible

A streamline and an equipotential line in a flow field:

a) Are parallel to each other
b) Are perpendicular to each other
c) Intersect at an acute angle
d) Are identical

Steady flow occurs when
a) The direction and magnitude of the velocity at all points are identical
b) The velocity of successive fluid particles, at any point, is the same at successive periods of time
c) The magnitude and direction of the velocity do not change from point to point in the fluid
d) The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane

Non uniform flow occurs when
a) The direction and magnitude of the velocity at all points are identical
b) The velocity of successive fluid particles, at any point, is the same at successive periods of time
c) Velocity, depth, pressure, etc. change from point to point in the fluid flow
d) The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane

A one dimensional flow is one which
a) Is uniform flow
b) Is steady uniform flow
c) Takes place in straight lines
d) Involves zero transverse component of flow

In a forced vortex, the velocity of flow everywhere within the fluid is
a) Maximum
b) Minimum
c) Zero
d) Nonzero finite

According to Bernoulli's equation
a) Z + p/w + v²/2g = constant
b) Z + p/w - v²/2g = constant
c) Z - p/w + v²/2g = constant
d) Z - p/w - v²/2g = constant

The loss of pressure head in case of laminar flow is proportional to
a) Velocity
b) (Velocity)²
c) (Velocity)³
d) (Velocity)⁴

The loss of head due to viscosity for laminar flow in pipes is (where d = Diameter of pipe, l = Length of pipe, v = Velocity of flow, w = Specific weight of the flowing liquid)
a) 4
b) 8
c) 16
d) 32

The velocity at which the flow changes from laminar flow to turbulent flow is called
a) Critical velocity
b) Velocity of approach
c) Sub-sonic velocity
d) Super-sonic velocity

Reynolds number is significant in
a) Supersonics, as with projectile and jet propulsion
b) Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
c) Simultaneous motion through two fluids where there is a surface of discontinuity, gravity forces, and wave making effect, as with ship's hulls
d) All of the above

The flow in a pipe is neither laminar nor turbulent when Reynold number is
a) Less than 2000
b) Between 2000 and 2800
c) More than 2800
d) None of these

Flow through a hole in wash basin is:
a) Steady flow
b) Uniform flow
c) Free vortex
d) Forced vortex

Gradually varied flow is
a) Steady uniform
b) Non-steady non-uniform
c) Non-steady uniform
d) Steady non-uniform

A flow through a long pipe at constant rate is called
a) Steady uniform flow
b) Steady non-uniform flow
c) Unsteady uniform flow
d) Unsteady non-uniform flow

A flow through a long pipe at decreasing rate is called __________ uniform flow.
a) Steady
b) Unsteady
c) Both A and B
d) None of these

According to Bernoulli's equation for steady ideal fluid flow
a) Principle of conservation of mass holds
b) Velocity and pressure are inversely proportional
c) Total energy is constant throughout
d) The energy is constant along a streamline but may vary across streamlines

Bernoulli equation deals with the law of conservation of
a) Mass
b) Momentum
c) Energy
d) Work

Reynold's number is the ratio of inertia force to
a) Pressure force
b) Elastic force
c) Gravity force
d) Viscous force

The continuity equation is connected with
a) Open channel/pipe flow
b) Compressibility of fluids
c) Conservation of mass
d) Steady/unsteady flow

Which of the following statement is correct?
a) In a compressible flow, the volume of the flowing liquid changes during the flow
b) A flow, in which the volume of the flowing liquid does not change, is called incompressible flow
c) When the particles rotate about their own axes while flowing, the flow is said to be rotational flow
d) All of the above

True one-dimensional flow occurs when
a) The direction and magnitude of the velocity at all points are identical
b) The velocity of successive fluid particles, at any point, is the same at successive periods of time
c) The magnitude and direction of the velocity do not change from point to point in the fluid
d) The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane

The discharge in an open channel corresponding to critical depth is
a) Zero
b) Minimum
c) Maximum
d) None of these

The total energy of each particle at various places in the case of perfect incompressible fluid flowing in continuous stream
a) Keeps on increasing
b) Keeps on decreasing
c) Remain constant
d) May increase/decrease

The flow in which each liquid particle has a definite path and their paths do not cross each other is called
a) One dimensional flow
b) Streamline flow
c) Steady flow
d) Turbulent flow

In one dimensional flow, the flow
a) Is steady and uniform
b) Takes place in straight line
c) Takes place in curve
d) Takes place in one direction

Fluid Dynamics

A flow is said to be laminar when
a) the fluid particles move in a zig-zag way
b) the Reynold's number is high
c) the fluid particles move in layers parallel to the boundary
d) none of the above

If the fluid particles move in straight lines and all the lines are parallel to the surface, the flow is called
a) turbulent
b) uniform
c) compressible
d) laminar

An orifice is called a large orifice if water head is
a) two times the diameter
b) three times the diameter
c) five times the diameter
d) ten times the diameter

Venturimeter is used to measure
a) discharge (rate of flow)
b) point velocity
c) static pressure
d) all of the above

What is the relationship between Orificemeter diameter and pipe diameter?
a) Orificemeter diameter is 0.5 times the pipe diameter
b) Orificemeter diameter is one third times the pipe diameter
c) Orificemeter diameter is one fourth times the pipe diameter
d) Orificemeter diameter is equal to the pipe diameter

In Venturi's divergent section:
a) Constant pressure
b) Pressure increases
c) Pressure decreases
d) Mass-dependent

The coefficient of discharge is __________ the coefficient of velocity:
a) Less than
b) Same as
c) More than
d) None

A flow where viscosity dominates inertia is called:
a) Steady flow
b) Unsteady flow
c) Laminar flow
d) Turbulent flow

A notch measures:
a) Pressure
b) Discharge (Q)
c) Velocity
d) Volume

Coefficient of velocity (Cv) is:
a) Actual velocity/theoretical velocity at vena contracta
b) Contracta area/orifice area
c) Actual/theoretical discharge
d) None

Identify the Bernoulli's equation where each term represents energy per unit mass
a) v²/2g + p/w + z = constant
b) v²/2 + p/ρ + gz = constant
c) pv²/g + gp/ρ = constant
d) None of these

Study of fluid motion with the forces causing the flow is known as
a) Kinematics of fluid flow
b) Dynamatics of fluid flow
c) Dynamics of fluid flow
d) None of above

The term v²/2g is known as
a) Potential energy
b) Pressure energy
c) Kinetic energy per unit weight
d) None of the above

The term p/w is known as
a) Kinetic energy per unit weight
b) Pressure energy
c) Pressure energy per unit weight
d) Potential energy

The term Z is known as
a) Potential energy
b) Potential energy per unit weight
c) Pressure energy
d) Pressure energy per unit weight

The difference of pressure head (h) measured by mercury-oil differential manometer is given by
a) (S₂ - S₁)x
b) (S₁/S₂)x
c) (S₂/S₁)x
d) (S₂ - S₁)x

Pitot-tube is used to measure
a) Discharge
b) Average Velocity
c) Velocity at a point
d) Pressure at a point

Venturimeter is used to measure
a) Discharge
b) Average velocity
c) Velocity at a point
d) Pressure at a point

Orifice meter is used to measure
a) Discharge
b) Average velocity
c) Velocity at a point
d) Pressure at a point

The rate of flow through venturimeter varies as
a) H
b) H²
c) H³/²
d) H¹/²

The kinetic energy correction factor for laminar flow through a circular pipe is approximately equal to
a) 1.0
b) 1.5
c) 2.0
d) 2.25

The Bernoulli's equation deals with the law of conservation of
a) mass
b) work
c) length
d) energy

Which of the following is not the assumption made in Bernoulli's equation?
a) The fluid is ideal
b) The fluid is compressible
c) The flow is irrotational
d) The flow is steady

The working principle of venturimeter is based on
a) Bernoulli's equation
b) Momentum equation
c) Continuity equation
d) None of the above

The difference between the total head line and the hydraulic grade line represents the:
A. Piezometric head
B. Pressure head
C. Elevation head
D. Velocity head

In which of the following conditions can the Bernoulli equation not be used?

a) Viscous flow
b) Incompressible fluid
c) Steady flow
d) Laminar flow

The pressure of the liquid flowing through the divergent portion of a Venturimeter
a) Remains constant
b) Increases
c) Decreases
d) Depends upon mass of liquid

An opening in the side of a tank or vessel such that the liquid surface with the tank is below the top edge of the opening, is called
a) Weir
b) Notch
c) Orifice
d) None of these

A weir is said to be narrow-crested weir, if the width of the crest of the weir is __________ half the height of water above the weir crest
a) Equal to
b) Less than
c) More than
d) None of these

When the water level on the downstream side of a weir is above the top surface of a weir, the weir is known as
a) Narrow-crested weir
b) Broad-crested weir
c) Ogee weir
d) Submerged weir

Coefficient of velocity is defined as the ratio of
a) Actual velocity of jet at vena contracta to the theoretical velocity
b) Area of jet at vena contracta to the area of orifice
c) Actual discharge through an orifice to the theoretical discharge
d) None of the above

The error in discharge (dQ/Q) to the error in measurement of head (dH/H) over a triangular notch is given by
a) dQ/Q =3/2 × (dH/H)
b) dQ/Q =2 × (dH/H)
c) dQ/Q =5/2 × (dH/H)
d) dQ/Q =3 × (dH/H)

According to Manning's formula, the discharge through an open channel is (where M = Manning's constant)
a) A ×M ×m1/2 ×i2/3
b) A ×M ×m2/3 ×i1/2
c) A1/2 × M2/3 × m × i
d) A2/3 × M1/3 × m × i

Differential manometer is used to measure
a) Pressure in pipes, channels etc.
b) Atmospheric pressure
c) Very low pressure
d) Difference of pressure between two points

An air vessel is provided at the summit in a siphon to
a) Avoid interruption in the flow
b) Increase discharge
c) Increase velocity
d) Maintain pressure difference

The hammer blow in pipes occurs when
a) There is excessive leakage in the pipe
b) The pipe bursts under high pressure of fluid
c) The flow of fluid through the pipe is suddenly brought to rest by closing of the valve
d) The flow of fluid through the pipe is gradually brought to rest by closing of the valve

The velocity of jet of water travelling out of opening in a tank filled with water is proportional to
a) Head of water (h)
b) h²
c) √h
d) h/2

According to Darcy's formula, the loss of head due to friction in the pipe is (where f = Darcy's coefficient, l = Length of pipe, v = Velocity of liquid in pipe, and d = Diameter of pipe)
a) flv²/2gd
b) flv²/gd
c) 3flv²/2gd
d) 4flv²/2gd

The discharge through a convergent mouthpiece is __________ the discharge through an internal mouthpiece of the same diameter and head of water.
a) Equal to
b) One-half
c) Three fourth
d) Double

Venturimeter is used to
a) Measure the velocity of a flowing liquid
b) Measure the pressure of a flowing liquid
c) Measure the discharge of liquid flowing in a pipe
d) Measure the pressure difference of liquid flowing between two points in a pipe line

The Cipoletti weir is a __________ weir.
a) Rectangular
b) Triangular
c) Trapezoidal
d) Circular

The maximum discharge over a broad crested weir is
a) 0.384 Cd × L × H¹/²
b) 0.384 Cd × L × H³/²
c) 1.71 Cd × L × H¹/²
d) 1.71 Cd × L × H³/²

A Piezometer tube is used only for measuring
a) Low pressure
b) High pressure
c) Moderate pressure
d) Vacuum pressure

Pressure of the order of 10⁻⁶ torr can be measured by
a) Bourdon tube
b) Pirani Gauge
c) Micro-manometer
d) Ionisation gauge

A pitot tube is used to measure the
a) Velocity of flow at the required point in a pipe
b) Pressure difference between two points in a pipe
c) Total pressure of liquid flowing in a pipe
d) Discharge through a pipe

The critical depth meter is used to measure
a) Velocity of flow in an open channel
b) Depth of flow in an open channel
c) Hydraulic jump
d) Depth of channel

Flow of water in a pipe about 3 metres in diameter can be measured by
a) Orifice plate
b) Venturimeter
c) Rotameter
d) Pitot tube

Which of the following instruments is used to measure flow on the application of Bernoulli's theorem?
a) Venturimeter
b) Orifice plate
c) Nozzle
d) All of the above

Momentum Analysis

Principle of similitude forms the basis of
a) Comparing two identical equipments
b) Designing models so that the result can be converted to prototypes
c) Comparing similarity between design and actual equipment
d) Hydraulic designs

The rise of liquid along the walls of a revolving cylinder about the initial level is __________ the depression of the liquid at the axis of rotation.
a) Same as
b) Less than
c) More than
d) None of these

Euler's dimensionless number relates the following
a) Inertial force and gravity
b) Viscous force and inertial force
c) Viscous force and buoyancy force
d) Pressure force and inertial force

The ratio of the inertia force to the __________ is called Euler's number
a) Pressure force
b) Elastic force
c) Surface tension force
d) Viscous force

Select the correct statement
a) Weber's number is the ratio of inertia force to elastic force
b) Weber's number is the ratio of gravity force to surface tension force
c) Weber's number is the ratio of viscous force to pressure force
d) Weber's number is the ratio of inertia force to surface tension force

For similarity, in addition to models being geometrically similar to prototype, the following in both cases should also be equal
a) Ratio of inertial force to force due to viscosity
b) Ratio of inertial force to force due to gravitation
c) Ratio of inertial force to force due to surface tension
d) All the four ratios of inertial force to force due to viscosity, gravitation, surface tension, and elasticity

Mach number is significant in
a) Supersonics, as with projectiles and jet propulsion
b) Full immersion or completely enclosed flow, as with pipes, aircraft wings, nozzles etc.
c) Simultaneous motion through two fluids where there is a surface of discontinuity, gravity force, and wave making effects, as with ship's hulls
d) All of the above

When the Mach number is between __________ the flow is called super-sonic flow
a) 1 and 2.5
b) 2.5 and 4
c) 4 and 6
d) 1 and 6

A flow is called hyper-sonic, if the Mach number is
a) Less than unity
b) Unity
c) Between 1 and 6
d) None of these

A flow is called super-sonic if the
a) Velocity of flow is very high
b) Discharge is difficult to measure
c) Mach number is between 1 and 6
d) None of these

The value of bulk modulus of a fluid is required to determine
a) Reynold's number
b) Froude's number
c) Mach number
d) Euler's number

A piece of wood having weight 5 kg floats in water with 60% of its volume under the liquid. The specific gravity of wood is
a) 0.83
b) 0.6
c) 0.4
d) 0.3

The specific weight of sea water is __________ that of pure water.
a) Same as
b) Less than
c) More than
d) None of these

Alcohol is used in manometers because
a) It has low vapour pressure
b) It is clearly visible
c) It has low surface tension
d) It can provide longer column due to low density

The discharge over a rectangular notch is
a) Inversely proportional to H³/²
b) Directly proportional to H³/²
c) Inversely proportional to H⁵/²
d) Directly proportional to H⁵/²

According to Francis formula, the discharge over a rectangular weir is (where n = Number of end contractions)
a) (2/3) × Cd (L - nH) × √(2g) × H²
b) (2/3) × Cd (L - 0.1nH) × √(2g) × H³/²
c) (2/3) × Cd (L - nH) × √(2g) × H⁵/²
d) (2/3) × Cd (L - nH) × √(2g)

Similitude and Physical Modeling

Euler's number relates:
a) Inertial/gravity forces
b) Viscous/inertial forces
c) Viscous/buoyancy forces
d) Pressure/inertial forces

For complete similarity between model and prototype, which ratios must match?
a) Inertial/viscous (Re)
b) Inertial/gravitational (Fr)
c) Inertial/surface tension (We)
d) All dimensionless ratios (Re, Fr, We, Ma)

Similitude principle is used for:
a) Comparing identical equipment
b) Scaling model results to prototypes
c) Design-actual comparison
d) Hydraulic designs

The torque required to overcome viscous resistance of a collar bearing is (where R1 and R2 = External and internal radius of collar)
a) ×
b)
c)
d) × ( - )

The Newton's law of resistance is based on the assumption that the
a) Planes of the body are completely smooth
b) Space around the body is completely filled with the fluid
c) Fluid particles do not exert any influence on one another
d) All of the above

The force exerted by a moving fluid on an immersed body is directly proportional to the rate of change of momentum due to the presence of the body. This statement is called
a) Newton's law of motion
b) Newton's law of cooling
c) Newton's law of viscosity
d) Newton's law of resistance

In order that flow takes place between two points in a pipeline, the differential pressure between these points must be more than
a) Frictional force
b) Viscosity
c) Surface friction
d) All of the above

The power absorbed (in watts) in overcoming the viscous resistance of a footstep bearing is
a) μN²R²/1800t
b) μN²R²/3600t
c) μN²R²/7200t
d) μN²R²/900t

In a footstep bearing, if the speed of the shaft is doubled, then the torque required to overcome the viscous resistance will be
a) Double
b) Four times
c) Eight times
d) Sixteen times

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