Section 10 Flashcards
A globe valve is the most suitable for applications, in which
a. fluid flow control is required.
b. fluid contains dispersed solid particles.
c. valve is required to be either fully open or fully closed.
d. one way flow is required.
a. fluid flow control is required.
2._____isused for measuring the static pressure exerted on the wall by a fluid flowing parallel to the wall in a pipeline.
a. Venturimeter
b. Pressure gauge
c. Pitot tube
d. Orificemeter
c. Pitot tube
One stoke (unit of kinematic viscosity) is equivalent to
a. 1 cm^2/second
b. 1 m^2/second
c. 1 gm/cm. second
d. 1 kg . m/second
a. 1 cm^2/second
Air vessel of a reciprocating pump is initially filled with
a. atmospheric air
b. compressed air
c. water
d. none of these
b. compressed air
The ratio of inertial forces to gravity forces is called the ___ number.
a. Mach
b. Froude
c. Euler
d. Weber
b. Froude
Power required by a centrifugal pump is proportional to (where, D = diameter, N = r.p.m)
a. N^2D^3
b. ND^2
c. N^2D
d. N^3D^5
d. N^3D^5
Equivalent length of a pipe fitting is
a. dependent on Reynolds number.
b. independent of Reynolds number.
c. dependent on the length of the pipe.
d. none of these.
a. dependent on Reynolds number.
Buckingham-π theorem states that in any physical problem including ‘n’ quantities having ‘m’ diamensions, the quantities can be arranged into __________ independent dimensionless parameters.
a. m
b. n
c. n-m
d. n/m
c. n-m
A fluid which has a linear relationship between the magnitude of applied shear-stress and the resulting rate of deformation is called a/an __________ fluid.
a. Newtonion
b. Non-Newtonion
c. ideal
d. incompressible
a. Newtonion
Existence of boundary layer in fluid flow is because of the
a. surface tension
b. fluid density
c. fluid viscosity
d. gravity forces
c. fluid viscosity
In case of laminar flow of fluid through a circular pipe, the
a. shear stress over the cross-section is proportional to the distance from the surface of the pipe.
b. surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder.
c. velocity profile varies hyperbolically and the shear stress remains constant over the cross-section.
d. average flow occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius).
b. surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder.
Which of the following facilitates close control of flow of fluids ?
a. Gate valve
b. Globe valve
c. Butterfly valve
d. Check valve
b. Globe valve
For an ideal fluid flow, Reynolds number is
a. 2100
b. 100
c. 0
d. ∞
d. ∞
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
a. 0.01 to 0.1
When a fluid flows over a solid surface, the
a. velocity is uniform at any cross-section.
b. velocity gradient is zero at the solid surface.
c. resistance between the surface & the fluid is lesser as compared to that between the fluid layers themselves.
d. velocity is not zero at the solid surface.
b. velocity gradient is zero at the solid surface.
Pick out the wrong statement about cavitation.
a. Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation.
b. Cavitation may be caused due to boiling of liquid by decreasing the pressure resulting in formation & collapse of vapor cavities.
c. Cavitation begins at higher static pressure and lower velocity in larger diameter pipelines resulting in audible noise.
d. Large scale cavitation can not damage pipeline, restrict fluid flow and damage steam turbine blades.
d. Large scale cavitation can not damage pipeline, restrict fluid flow and damage steam turbine blades.
The maximum delivery pressure of a reciprocating compressor may be about __________ kg/cm2.
a. 1000
b. 2000
c. 3000
d. 4000
d. 4000
The velocity for subsonic flow in a pipeline
a. increases in the downstream direction.
b. is constant.
c. decreases in the downstream direction.
d. is independent of the area of flow.
a. increases in the downstream direction.
Permanent pressure loss in a well designed venturimeter is about _____ percent of the venturi differential.
a. 1
b. 10
c. 30
d. 50
b. 10
The ratio of pressure forces to inertial forces is called the __________ number.
a. Froude
b. Euler
c. Reynold
d. Mach
b. Euler
Bernoulli’s equation for fluid flow is derived following certain assumptions. Out of the assumptions listed below, which set of assumptions is used in derivation of Bernoulli’s equation ?
A. Fluid flow is frictionless & irrotational.
B. Fluid flow is steady.
C. Fluid flow is uniform & turbulent.
D. Fluid is compressible.
E. Fluid is incompressible.
a. A, C, D
b. B, D, E
c. A, B, E
d. A, D, E
c. A, B, E
Cavitation in a centrifugal pump results from
a. high discharge pressure
b. low barometric pressure
c. high discharge velocity
d. high discharge rate
b. low barometric pressure
For turbulent flow of newtonion fluid in a circular cross-section pipe, the ratio of maximum to average fluid velocity is
a. 0.5
b. 1
c. 0.66
d. < 0.5
b. 1
Water is flowing at 1 m/sec through a pipe (of 10 cm I.D) with a right angle bend. The force in Newtons exerted on the bend by water is
a. 102π
b. 5π/2
c. 52π
d. 5π/2
b. 5π/2
The time of oscillation of a floating body is
a. longer, if metacentric height is increased.
b. independent of the metacentric height.
c. dependent on the buoyant forces only.
d. none of these.
d. none of these.
What is the value of Fanning friction factor f ‘ for smooth pipe at NRe = 106 approximately ?
a. 0.003
b. 0.01
c. 0.1
d. 0.3
a. 0.003
Air vessel provided in a reciprocating pump is for
a. increasing the acceleration head.
b. making the friction in pipe uniform.
c. decreasing the acceleration head.
d. none of these.
b. making the friction in pipe uniform.
A hydraulic accumulator comprises of
a. a storage device and a control valve.
b. a cylinder and a plunger.
c. two pistons and two cylinders.
d. a storage tank and a ram pump.
b. a cylinder and a plunger.
Prandtl mixing length is
a. applicable to laminar flow problems.
b. a universal constant.
c. zero at the pipe wall.
d. none of these.
c. zero at the pipe wall.
A tube is specified by its
a. thickness only
b. outer diameter only
c. thickness & outer diameter both
d. inner diameter
c. thickness & outer diameter both
Bernoulli’s equation for steady, frictionless, continuous flow states that the __________ at all sections is same.
a. total pressure
b. total energy
c. velocity head
d. none of these
b. total energy
The hydraulic diameter of an annulus of inner and outer radii Ri and Ro respectively is
a. 4(Ro-Ri)
b. Ro-Ri
c. 2(Ro-Ri)
d. Ro + Ri
c. 2(Ro-Ri)
With the increase in depth, the hydrostatic pressure in an unaccelerated incompressible fluid (in a constant gravitational field)
a. decreases.
b. increases linearly.
c. increases exponentially.
d. remains constant.
b. increases linearly.
Ratio of inertial forces to surface tension forces is called the __________ number.
a. Euler
b. Froude
c. Mach
d. Weber
d. Weber
In open channel flow in a rectangular channel, the ratio between the critical depth and the initial depth, when a hydraulic jump occurs is
a. 0.5
b. 0.84
c. 1.84
d. 1.25
c. 1.84
The ratio of inertial forces to viscous forces is called the __________ number.
a. Weber
b. Mach
c. Froude
d. Reynold
d. Reynold
Enamels and paints are generally __________ fluid.
a. reheopectic
b. pseudo-plastic
c. thixotropic
d. dilatant
b. pseudo-plastic
Flow measurement in an open channel is done by a/an
a. venturimeter
b. orificemeter
c. weir
d. rotameter
c. weir
Newton’s law of viscosity relates the
a. shear stress and velocity.
b. velocity gradient and pressure intensity.
c. shear stress and rate of angular deformation in a fluid.
d. pressure gradient and rate of angular deformation.
c. shear stress and rate of angular deformation in a fluid.
The equivalent diameter for fluid flow through square cross section channel of side ‘x’, for pressure drop calculation purpose is given by
a. 4x
b. 2x
c. x
d. x
c. x
Hydraulic radius of 6” x 12” cross-section, is __________ inches.
a. 2
b. 0.5
c. 1.5
d. none of these
a. 2
Baffles in mixing tanks are provided to
a. reduce swirling and vortex formation.
b. increase the structural strength of the tank.
c. aid in rotational flow.
d. none of these
a. reduce swirling and vortex formation.
Which of the following equations is valid for laminar flow of a fluid through packed bed?
a. Fanning equation
b. Kozney - Karman equation
c. Hagen-Poiseuille equation
d. Blake-Plummer equation
b. Kozney - Karman equation
