Momentum transfer
1. The fluid property, due to which, mercury does not wet the glass is surface tension. 2. Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds number exceeds 2100. 3. When the momentum of one fluid is used for moving another fluid, such a device is called a/an jet a/an jet pump. pump. 4. The normal stress is the same in all directions at a point in a fluid, when the fluid is having no motion of one fluid layer relative to the other. 5. Head developed by a centrifugal pump depends on its speed & impeller diameter. diameter . 6. Hydraulic mean depth D Dm! for a circular pipe of diameter "#" flowing full is $%&' #% (or a circular channel, at Dm ) $%* #, gives the condition for the maximum mean velocity 2 7. The head loss in turbulent flow in a pipe varies as veloci ve locity! ty! . ". +ost commonly used oint in the underground underground pipe lines is the sleeveoint #. -chedule number of a pipe, which is a measure of its wall thic.ness, is given by $$$ 0"/10. The net positive suction head N0-H! of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the suction minus vapor pressure pressure of the li1uid at suction temperature% temperature% 11. With increasing flow rate, the hydraulic efficiency of a centrifugal pump monotonically decreases% 12. The velocity profile for turbulent flow through a closed conduit is logarithmic% 13. 2n case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, number, whereas for a hydraulically rough pipe, the resistance to flow is governed governed by the relative roughness% Two pipes are said to have the same hydraulic roughness, when they have e1ual values of friction co$efficient for flo%s at e ual 'eynold num(er. 14. Water hammer in a pipeline results from the rapid pressure change due to a rapid change in the rate of flo%. 15. +olten soap mass is transported by a 3 gear pump% 16. The effect of compressibility in fluid f low is denoted by a number as )ach num(er. 17. Nominal si4e of the discharge pipe of a pump is usually *smaller usually *smaller than the nominal si4e of the inlet pipe% 1". The terminal velocity of a small sphere settling in a viscous fluid varies as the inverse of the fluid viscosity. 1#. 2f the discharge of a centrifugal pump is throttled, then its suction lift increases 20. (oot valves provided in pumps are directional control valves% control valves% 21. 5t high Reynolds number inertial forces control and viscous forces are unimportant. 22. 0ower loss in an orificemeter is more than that than that in a venturimeter% n 23. The terminal velocity of a particle moving through a fluid varies as dp % What is the value of n" for Newton"s law regime 0.5. 24. the normal range of exit cone angle of a venturimeter 2 to 5. $1 $1 25. The dimension of dynamic viscosity is )+ , % 26. 5 particle 5 of diameter $ microns settles in an oil of specific gravity $%6 and viscosity $ poise under -to.e"s law% 5 particle 7 with diameter &$ microns settling in the same oil will have a settling velocity one fourth as that of -. 27. The pitot static tube does not measure the statictotaldifferen statictotaldifference ce in static & dynamic pressure% 2". The fluid in which the shearing stress within it is proportional to the velocity gradient across the sheared section, is called a perfect fluid% perfect fluid% 2#. 2n fluid flow, cavitation is caused, if the flo% pressure approaches its vapor pressure at the prevailing temperature.
30. The ratio of the depth of flow to the hydraulic radius for the most economical trape4oidal section, in open channel flow is 2. 31. The drag co8efficient for a bacterium moving in water at mm/s, will be of the following order of magnitude assume si4e of the bacterium to be micron and .inematic viscosity of 89
&
water to be $ m /s! 0.44. 32. (or Laminar flow through a pac.ed bed, the pressure drop is proportional to V s is the 2
superficial li1uid velocity and D p is the particle diameter! V s/D p 33. The maximum delivery pressure of compressors can be upto 1000 atmospheres% $1 34. #imension of surface tension iswhere, F ) force, L ) length! FL 35. :o8efficient of velocity is more than the coefficient of discharge% 36. 5ll pipes of a particular nominal si4e have the same outside diameter 37. (or the transfer of solution of thic. slurry, the pump used is a diaphragm pump% 3". +aximum theoretical suction lift for water at ';: by a centrifugal pump is *< ft% The same for water at 6$;: will be " ft% 3#. 0ressure drag does not depend upon the roughness of surface of the (ody pressure of main flo% only & length of the (ody in flo% direction. $1 $1 40. #imension of absolute viscosity is )+ , 41. ropeller pumps are axial flow pumps% 42. 7rownian movement is prominent in the particle si4e range of 2 to 3 microns in case of settling of a particle in a fluid% 43. (or a particle settling in water at its terminal settling velocity %eight(uoyancydrag. 44. 5 7ingham fluid of viscosity = ) $ 0a%s and yield stress, >$ ) $ ?0a, is shared between flat 8*
parallel plates separated by a distance of $ m% The top plate is moving with a velocity of m/s% The shear stress on the plate is 20 a. 45. The resistance wire used in a hot wire anemometer for conducting electrical current is made of tungsten. 46. Two dimensional stream function is constant along a stream line % 47. cavitation in centrifugal pump is due to +o% suction pressure. 4". #raining of shallow pits or sump is done by a sump pump, which is a single stage vertical pump% 4#. 5 hydraulic ram acts as a/an impulse pump% 50. The ratio of average fluid velocity to the maximum velocity in case of laminar flow of a Newtonion fluid in a circular pipe is 0.5 51. the correct set of dimensions of viscosity that are e1uivalent where, (, +, L, T are $2
$1 $1
dimensions for force, mass, length and time respectively!% + , )+ , 52. The line of action of the buoyant force passes through the centre of gravity of the displaced volume of the fluid 53. The friction factor for turbulent flow in a hydraulically smooth pipe depends only on Reynolds number% 54. The pressure at a point in a fluid is not the same in all directions, when the fluid is viscous and moving 55. The -to.e"s stream function applies to the cases of aial symmetry% 56. -lugging in a fluidised bed can be avoided by using shallo% (eds of solids and proper choice of particle sie. 57. The ratio of width to depth for the most economical rectangular section in open channel flow is 2 5". The simple pitot tube measures the total pressure% 5#. :apacity of a hydraulic accumulator is defined in terms of maximum amount of energy stored 60. Three piping networ.s as shown in the figure are placed hori4ontally% They are made using identical pipe segments and are subected to the same pressure drop across them% 5ssuming no pressure losses at unctions, the flow rates across the three networ.s are related as @ A @& A @*% 122
61. With diminishing cross8sectional area in case of subsonic flow in a converging no44le, the velocity increases, pressure decreases% 62. 7oundary layer separation is characterised by one of the conditions given below, where "Re" is the Reynolds number for the flow% -elect the appropriate conditions. 'e 881 decelerating flo% 63. +anometers measure the difference in pressure% 64. The fluid forces are not considered in the Navier8-to.e"s e1uation ,ur(ulent forces. 65. 2n turbulent flow, a rough pipe has the same friction factor as a smooth pipe %hen the roughness projections are much smaller than the thic9ness of the laminar film. 66. 7ernoulli"s e1uation is dependent on the mechanical energy euation 67. The capacity of an accumulator is the maximum energy which it can store% 6". With increase in the temperature, viscosity of a li1uid decreases 6#. Bena8contracta pressure tapping is at a distance 0.5 d from the position of an orificemeter fitted in a pipe of internal diameter "d " 70. The pump impeller and the turbine runner in a hydraulic tor1ue converter have different diameters 71. Reciprocating pumps compared to centrifugal pumps are not subect to air binding% 72. The fluid property which matters for fall8ing rain drops to ac1uire spherical shape is its surface tension 73. The simple pitot tube does not measure the static pressure, dynamic pressure, velocity at the stagnation point 74. 7oundary layer separation occurs when the cross8section of the channel is reduced% 75. The head loss in turbulent flow in a pipe varies approximately as the s1uare of the velocity 76. (or flow through an orifice from a reservoir, the actual velocity at the vena con8tracta is given by C.V.&gh½ 77. The ratio of the hydraulic radius to the diameter of the channel, for maximum mean velocity of flow in a circular channel, in open channel flow is $%* 7". (or the free settling of a spherical particle through a fluid, the slope of, :#8log NRe , plot is $1 7#. 5 centrifugal pump loses prime after starting% The reason of this trouble may be incomplete priming too high a suction lift. lo% availa(le :;< and air lea9s in the suction pipe. "0. Benturimeter and orificemeter measures the average velocity of the fluid% "1. -urge tan.s are provided in high pressure water pipelines to reduce the water hammer "2. 2n turbulent flow, a rough pipe has the same friction factor as a smooth pipe when the roughness proections are much smaller than the thic.ness of the laminar f ilm% "3. Hydraulic intensifier is used for increasing the intensity of pressure of the li1uid% 8$%&' "4. the "7laussius e1uation", relating friction factor to the Reynolds number is f ) $%$C6%N Re "5. Hydrometer measures the specific gravity of li1uids based on the principles of buoyancy% 0ycnometer is used to measure the specific gravity of powder D grannular solids "6. Euler"s e1uation of motion is a statement expressing conservation of mass%
"7. #uring ageing of fluid carrying pipes, the absolute roughness increases linearly with time "". +ass velocity is independent of temperature D pressure, when the flow is steady and the cross8section is unchanged% "#. Bery small pressure difference F ' mm water coloumn! can be most conveniently measured by a/an inclined tu(e %ater manometer% 5 #0. (or pipe flows, head is proportional to 1/D at constant capacitywhere, D ) pipe diameter!%
#1. The energy e1uation, The energy e1uation, E ) internal energy/mass!, is applicable to E ) internal energy/mass!, is applicable to all compressi(le fluids. #2. 5 differential pressure cell is used for remote recording of pressure difference% #3. 2f more than two branches of pipes are to be connected at the same point, then use a/an tee #4. 2n case of a centrifugal pump, the ratio of total delivered pressure to pressure developed with the impeller is called the manometricefficiency% #5. 5cceleration head in a reciprocating pump does not change the wor. re1uirement of the pump #6. The ratio of inertial forces to elastic forces is called the )ach num(er% #7. (luid flow at increasing rate through a diverging pipe is an example of non$steady non$ uniform flow% #". The temperature in isentropic flow depends on +ach number only & & ##. 5 fluid element has a velocity B ) 8y % xi G &yx % % The motion at x, y! ) l/&, ! is rotational and compressible% 100. chec. in a centrifugal pump is provided in the discharge line% 101. :entrifugal pump is normally classified on the basis of the type of casing% 102. Where does the maximum stress occur in case of laminar flow of incompressible fluid in a closed conduit of diameter "d" 5t the wall 103. 2n case of isentropic flow, the speed of sound in an ideal gas is proportional to where, T ) absolute temperature ! T 1/2 104. 5pplying a pressure drop across a capillary results in a volumetric flow rate "Q" under laminar flow conditions% The flow rate for the same pressure drop, in a capillary of the same length but half the radius is Q /9 105.:hec. valves are used for unidirectional flow 106. Belocity distribution for flow between two fixed parallel plates varies parabolically across the section% 107.0riming is needed in a centrifugal pump% 10".5n ideal no44le design aims at minimising wall friction, suppressing boundary layer separation% 10#.(or ideally incompressible fluid, the +ach number will be 110.5 mono pump is a positive acting rotary pump% 111.Higher specific speed &$$8'$$! of a centrifugal pump indicates that the pump is of aial flow type% 112.The variable re1uired to be .nown in correlations used for estimating the horse power of a centrifugal gas compressor and hence its cost are 0% 2nlet pressure @% :ompressor rpm R% #elivery pressure -% Bolumetric flow rate at inlet% 5N-A = and ' 113.Theoretical head developed by a centrifugal pump does not depend upon the radius of speed of fluid velocity leaving the impeller% 114.5n ideal fluid is non8viscous, incompressible
115.the Hagen80oiseulle"s e1uation%
116.2n case of isentropic flow, the speed of sound in an ideal gas is proportional to where M ) molecular weight of the gas! /M 1/2 117.7oundary layer separation is caused by the reduction of pressure gradient to 4ero% 11".With increase in temperature, the vapor pressure of li1uids increases 11#.5 mercury specific gravity ) *%9! manometer connected across an orificemeter fitted in a pipe shows a manometer reading of & cms% 2f the manometer li1uid is changed to carbon tetrachloride specific gravity ) %9!, then for the same flow rate of water the new manometer reading will be 17 cms. 120.The ratio of wall drag to total drag in the -to.e"s law range is 2/3 121.Rotary vacuum pumps can reduce the absolute pressure to as low as 0.01 mm Hg% 122.5 pitched8blade turbine draws less po%er than a straight blade turbine% 123.The most suitable flow measuring device for the fluid flow measurement in a very large diameter pipeline is a pitot tube 124.5 centrifugal pump is called a turbine pump, if it is having a vaned diffusion casing 125.Remote control valve is a (utterfly valve% 126.:entre of pressure in an immersed body is (elo% the centre of gravity% 127.The centre of pressure is a point on the line of action of the resultant force. 12".The uniformity of a gas fluidised bed depends upon the sie surface properties of the solid particles% 12#.2n a fluidised bed reactor temperature is more or less uniform% 130.The flow of a li1uid through tapering pipe at a constant rate is an example of steady non uniform flo%. 131.5 perfect gas has constant specific heat. 132.2n a/an pitot tu(e, the flow rate of fluids is obtained by measuring the difference between the impact and the static pressure%
133.#uring fluid flow, variation of shear stress>! with velocity gradientat temperature is shown below in the figure
2n the above figure, 7inghom plastic is represented by the curve % 134.-peed of sound in an ideal gas depends on its temperature
5N-A 22
constant pressure
135.5 centrifugal pump designed for handling water = ) cp! will deliver less head & capacity when pumping a thic.er oil = ) *$ cp!% 136.2f "x" is the depth of flow in an open channel of large width, then the hydraulic radius is e1ual to 137.(or a given fluid flow rate, which of the following incurs maximum head loss >rifice meter 13".2n case of a pipe exit fitted with a no44le, the conversion of pressure head to .inetic head is facilitated% 13#.5 fluid whose apparent viscosity increases with shear rate is termed as the dilatants fluid% 140.Transition length for a turbulent fluid entering into a pipe is around 50 times the pipe diameter% 141.(or turbulent flow of an incompressible fluid through a pipe, the flow rate @ is proportional to 0!n, where 0 is the pressure drop% The value of exponent "n" is ? 1 142.Reciprocating pumps are not able to compete with the centrifugal pump for industrial use, mainly because these pumps have higher capital &maintenance cost. 143.the correct relationship for a centrifugal pump I where, # ) 2mpeller diameter, inches H ) $%'
Head developed, ft of li1uid pumped N ) -peed of pump, rpm! is # ) J<$ H /N 144.pipe bends will incur the largest head loss K8bend 145.the most efficient and best for measuring very small flow rate of gases 'otameter 146.When the water is warm, the height to which it can be lifted by a pump decreases due to reduced vapour pressure. 147.0ipes having diameter < inches or more are designated by their outside diameter 8* 8* 14".Biscosity of water at <$;: lies in the range of $%' x $ to x $ .g/m%s 14#.5 centrifugal pump has the following specificationsA 0ower ) < H%0% -peed ) J$$ rpm Head ) J metres (low ) $$$ litres/minutes% 2f its speed is halved, the new discharge will be 500 litres/minute% & 8 150.The dimension of .inematic viscosity is L T 151.5 pipe of 2%#% < m is bifurcated into two pipes of 2%#% & m each% 2f the average velocity of water flowing through the main pipe is ' m/sec, the average velocity through the bifurcated pipes is 10 m/sec 152.Lower 7WM means lo%er cross$section of the tube% 153.(or laminar flow of Newtonion fluid in a circular pipe, the velocity distribution is a function of the distance "d" measured from the centre line of the pipe, and it follows a para(olic 154.The 0randtl mixing length is useful for computing laminar flo% pro(lems % 155.N 2Re /N Fr is called the @alileo number% 156.The location of centre of pressure, which defines the point of application of the total pressure force on the surface, can be calculated by applying the principle of moments according to which sum of the moment of the resultant force about an axis is e1ual to the sum of the components about the same axis% The centre of pressure of a rectangular surface of width "w "! immersed vertically in a static mass of fluid is at a depth ofwhere, y ) depth of the li1uid! 2y /3 157.5s the velocity B and thus the Reynolds number of a flow past a sphere increases from very low value, the drag force for Re FF increases linearly %ith A. 15".-elf8priming centrifugal pump can be used for (ooster service pumping liuid fertilisers e.g. liuid :< 3! pumping industrial %astes. 15#.Water hammer is caused, when water flowing in a pipe is suddenly brought to rest by closing the valve% The extent of pressure thus produced due to water hammer depends on the pipe length, fluid velocity in the pipe, time ta.en to close the valve% 160.0ascal"s law is valid, only when the f luid is at rest% 161.5 centrifugal pump is used to pump water through a hori4ontal distance of '$ m, and then raised to an overhead tan. $ m above% The pipe is smooth with an 2%# of '$ mm% What head m *
of water! must the pump generate at its exit E! to deliver water at a flow rate of $%$$ m /sI The
(anning friction factor, f is $%$$9&%
ANS: m
162.The pressure head of a flow meter remains constant for rotameter 163.5 venturimeter can not be used for the direct measurement of datum difference in the stretch of pipeflow 164.5 double acting reciprocating pump compared to a single acting pump of almost same si4e wor.ing under same pressure levels! would give almost double discharge 165.The rate of shear versus the shear stress curves are time dependent for thiotropic rheopectic 166.2n Newton"s law range, the drag co8efficient for the motion of spherical particle in a stationary fluid is 0.44 2 167.5 pressure of $ m head of water is e1uivalent to #" 9:/m . 16".5 pressure head of *&$ metres of water in meters of ::l< sp%gr ) %9! will be 200 16#.the ?o4ney8?arman e1uation valid for low NRe! for fluid flow through a pac.ed bed of solids%
170.The ratio of the wall drag to the form drag in the -to.e"s law range for motion of spherical particles in a stationary fluid! is 2 171.(or turbulent flow in smooth circular pipe, the velocity distribution is a function of the distance "d" measured from the wall of the pipe and the friction velocity "v", and it follows a logarithmic 172.+aintenance cost of a centrifugal pump for a particular duty is the least% 173.:ho.ing in case of pipe flow means that a specified mass flo% rate can not (e achieved% 174.Belocity of li1uid hydrocarbon fuels in a pipeline can not be measured by magnetic flowmeters, because their electrical conductivity is very low/small% 175.The nominal si4e of a hose pipe is specified by its B.C% 176.Transition from laminar flow to turbulent flow is aided by the surface roughness and curvature i%e%sharp corners!, vibration%,pressure gradient and the compressibility of the flowing medium% 177.(or flow of fluids through pac.ed bed, the superficial velocity is less than the average velocity through channels. 17".C d is always greater than C c% 17#.7uoyant force depends on the %eight of the floating (ody.
1"0.:haracteristic curves for a centrifugal pump plotted against its capacity is shown in the diagram% x, y and 4 denote respectively
ANS: head, efficiency and 7%H%0% 1"1.Li1uid delivery by centrifugal pump starts, only when the head developed by it is e1ual to the manometric head% 1"2.The speed of sound in an ideal gas varies as the temperature 1"3.The maximum head that can be developed by a single impeller is 250$300 ft 1"4.The ratio of hydrodynamic boundary layer to thermal boundary layer thic.ness in case of li1uid metals is ? 1 1"5.The general relationship between speed N, head H, power 0 and discharge @ for a centrifugal &
*
pump is @∝N A H∝N A 0∝N 1"6.What is the ratio of the velocity at the axis of the pipe to the mean velocity of flow in case of pipe flow under viscous conditionI -:; 2 1"7.(oot valve provided in the pump is a (ac9 pressure valve% 1"".The discharge co8efficient for an orificemeter does not depend upon the pipe length% 1"#.Which of the following options will facilitate the achievement of a very high head say *$ metres! in case of a centrifugal pumpI -:; )ounting of t%o or more impellers in series on a single shaft% 1#0.5n e1uipotential line is normal to the velocity vector at every point%
1#1.-pecific speed for a centrifugal pump is 1#2.0ath followed by water et issuing from the bottom of a water tan. will be a para(ola verte (eing at the opening!. 1#3.Which of the following produces maximum pressure difference for transportation of gases I -:; Dompressors. 1#4.(or flow through a venturi at a particular discharge, the correct relationships among velocities at point O, P and Q would be ANS: A2 8 A1 and A 2 8 A3
1#5.#rag co8efficient in hindered settling is al%ays greater than that in free settling% 1#6.Efficiency of power transmission ! through a circular pipe is given by ht 8 hf !/ht, which has a maximum value of 66.6 percent% 1#7.Sne dimensional fluid flow implies the flo% in %hich transverse components are ero
1#". @ravity Crag Euoyant,forces act on a particle moving through a stationary f luid
1##.2n frictional fluid flow, the 1uantity, , is not constant along a streamline. 200.Hydraulic radius is the ratio of flo% area to %etted perimeter. 2 201.The unit of bul. modulus of elasticity for a li1uid in -%2% unit is :/m 202.0ower re1uirement of fans having constant wheel diameter varies as cu(e of 3333333333 fan speed% 203.2n the low Reynolds number region, the drag force on a sphere is proportional to A 204.The continuity e1uation represents the conservation of mass. 205.Experimental study of laminar fluid flow through a circular tube was conducted by
depth of H from the air8water iterfaceI The balloon is of radius $% m and is filled with air% 211.(or the laminar flow of a fluid in a circular pipe of radius R, the Hagen80oisseule e1uation 4
predicts the volumetric flow rate to be proportional to ' 212.2nterstage coolers are provided in a multistage compressor to save po%er in compressing a given volume to a given pressure. 213.:onsider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a li1uid of constant density at a particular discharge capacity% With decrease in the capacity of the pump, the :;< reuired. E< reuired (y the pump. head of the liuid pumped. 3333333333 decreases% 214.Reynolds number is the ratio of inertial forces to viscous forces. 215.(or the manometer set up shown in the figure, the pressure difference P A 8 P B is given by
ANS: H 8 air!Mh
216.The discharge through a venturimeter depends upon pressure drop only. & 217.N% second/m is the ;.B. unit of dynamic viscosity. 21".The distance between metacentre and 33 centre of gravity 33333333 is called metacentric height% 21#.:hec. valve is used for 333 unidirectional 3333333 flow% 220.:apacity of a rotary gear pump can be varied by changing the speed of rotation. (leeding air into suction. (ypassing liuid from the suction or discharge line. 221.(or a given Reynolds number, in a hydraulically smooth pipe, further smoothening 33 (rings a(out no further reduction of 33333333 the friction factor% 222.0ower number is the ratio of drag stress to inertial stress. 223.(or the same flow rate of a fluid, the pressure drop is the least for venturimeter 224.The valve commonly used in pipes larger than & dia is a gate valve 225.(oot valves are provided in the suction line of a centrifugal pump to avoid priming every time %e start the pump. 226.5n ideal fluid is frictionless & incompressi(le% 227.2n area meter e%g%, rotameter!, with increase in the fluid flow rate, the pressure drop is almost constant.
22".#rag co8officient :#, in -to.e"s law range is given by
22#.2n power law, , then the fluid is :e%tonian 230.The buoyant force acting on a floating body is dependent on the %eight of the liuid displaced.
231.5 Newtonion fluid is that for %hich shear & deformation are related as 232.2n case of end to end connection of two or more pipes in series, the same rate of flo% passes through each pipe% 233.Which of the following e1uations applies to the fluid flow through a pac.ed bed for very large Reynolds number I-:; Ela9e$llummer euation 234.The flow of gas along a pipe in the direction of decreasing pressure causes decrease in its specific volume 235.:entrifugal pump can"t be used to pump thic9 molten soap at "0FD. 236.5 stream line is fied in space in steady flo% % [email protected] is an example of a dilatent 23".:orrection for capillary effect in manometers used for pressure measurement! need not be applied, if diameter of the manometer tube is 8 12.5 mm% 23#.#ifferential manometer measures the pressure difference 240.The pressure and power re1uirement of a gas fan at constant speed D capacity varies directly as the gas density% 241.2sothermal turbulent flow of a fluid results in decrease of its pressure, which depends on the %all roughness 'eynolds num(er % 242.7oundary layer thic.ness in laminar flow over a flat plate increases aswhere, d ) distance from the leading edge%! d 1/2 243.Mradually varied flow in open channel is a/an steady non$uniform flow% 244.The line of action of the buoyant force acts through the centroid of the displaced volume of fluid. 245.:avitation in a centrifugal pump can be avoided by .eeping the inlet pressure high 246.Bane anemometer rotates an element at a speed determined (y the velocity of the fluid in %hich the meter is immersed. 247.The peripherial velocity at inlet of a centrifugal pump having inlet diameter of &' cms and rotating at 6'$ rpm is 12.4 m/sec%
24".Laminar flow is characterised by the nonexistence of pressure fluctuation eddies deviating velocities. 24#.The length of the tube necessary for the boundary layer to reach the centre of the tube and for fully developed flow to be established is called the transition length% 250.Hydraulic diameter for non8circular ducts is e1ual to four times the area of f low divided by the perimeter% 251.Terminal velocity is a constant velocity %ith no acceleration 252.:onsider two pipes of same length and diameter through which water is passed at the same velocity% The friction f actor for rough pipe is f and that for smooth pipe is f &% 0ic. out the correct statement. f 1 8 f 2 2
253.(or an incompressible fluid, the bul. modulus of elasticity is G :/m 254.5 fluid is a substance, that flo%s %hen even a small shear is applied to it. 255.The pressure intensity is the same in all directions at a point in a fluid %hen there is no motion of one fluid layer relative to an adjacent layer. 256.Which of the following must be followed by the flow of a fluid real or ideal!I 2! Newton"s law of viscosity% 22! Newton"s second law of motion% 222! The continuity e1uation% 2B! Belocity of boundary layer must be 4ero relative to boundary% B! (luid cannot penetrate a boundary% -:; BB BBB A 257.+ach number is defined as the ratio of the local f low velocity to the sonic velocity in the fluid% (or what value of +ach number, the gases are considered incompressible I -:; ? 0.3 25".7oundary layer exists in flow of real fluids% 25#.Rubber latex is an example of pseudoplastic fluid% 260.Belocity head on sudden enlargement in a hori4ontal pipe is converted into pressure head% 261.The frictional resistance in laminar flow does not depend on the area of surface in contact% 262.Mradually varying fluid flow is an example of non$steady uniform flow% 263.#rag is the force component exerted on an immersed obect, the component (eing parallel to theflo% direction. 264.To handle smaller 1uantity of fluid at higher discharge pressure, use a reciprocating pump% 265.:oc.s are used to control any liuid 266.2f in a flow field, between any two points, then the flow must be steady incompressi(le irrotational. $2 267.The dimension of surface tension is ), 26".Rubber latex is an example of a pseudoplastic fluid% 26#.The phenomenon occuring during pumping of a li1uid solution containing dissolved gases, which may come out of the solution giving rise to gas poc.ets, is termed as cavitation 270.Wor.ing of a tur(ine pump characterises mixed flow% 271.The e1uivalent diameter for pressure drop calculation for a fluid flowing through a rectangular cross8section channels having sides " " D "y " is given by -:; 272.The rate of change of moment of momentum represents the torue applied by the fluid% 273.C d for the orifice plate varies from 0.5" to 0." 5/2 274.The discharge through a B8notch weir varies as < 275.Water flow rate in a pipe of *%' metres diameter can be most economically and conveniently measured by a/an pitot tu(e 276.The specific speed of a pump is defined as the speed of a unit of such a si4e, that it delivers unit discharge at unit head. 277.2n case of venturimeters, friction losses are about 2 percent of maximum velocity head% 27".With increase in the schedule number of a pipe of a particular nominal si4e, the %all thic9ness also increases B.C. of the pipe decreases >.C. of the pipe remains constant. 27#.Turbine impeller is effective over %ide range of viscosities% 2"0.(riction produced by the formation of wa.es is called the form friction
2"1.Barious efficiencies of a centrifugal pump are related as where, m ) mechanical efficiency v ) volumetric efficiency% ma ) manometric efficiency o ) overall efficiency! -:; m ) v % ma 2"2.When the pipe Reynold"s number is 9$$$, the flow is generally tur(ulent
2"3.(anning e1uation is given by % 2t is applicable to laminartur(ulent region flow% 2"4.With a constant diameter impeller of a centrifugal pump head varies as the suare of speed% 2"5.(or water, when the pressure increases, the viscosity first decreases, and then increases
2"6.The head loss due to sudden expansion is -:; 2"7.Location of vena8contracta in an orificemeter does not depend upon the type of orifice% 2"".5t low Reynolds number viscous forces control and inertial forces are unimportant. 2"#.(or laminar flow through a closed conduit Ama 2Aav 2#0.2n Newton"s law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass varies as the suare root of its diameter% 2#1.Knsteady uniform flow is represented by flow through a/an long pipe at decreasing rate% 2#2.2f 7lausius or #arcey friction factor is "f " then the (anning friction factor is e1ual to f 1/4 2#3.While starting a centrifugal pump, its delivery valve should be .ept closed. 2#4.(or flow past a flat plate, if x is the distance along the plate in the direction of flow, the boundary layer thic.ness is proportional to 1/2 2#5.Belocity at a certain point in case of streamline flow is constant independent of time 2#6.-ewage sludge is an example of the Eingham plastic fluid% 2#7.2n case of a rotameter, the density of the float material is more than that of the li1uid it replaces% 2#".+ultistage centrifugal pumps are generally used for high head. 2##.The fluid et discharging from a & diameter orifice has a diameter of %C' at its vena8 contracta% The co8efficient of contraction is 0.766 * 300.5 bed consists of particles of density &$$$ .g/m % 2f the height of the bed is %' metres and its porosity $%9, the pressure drop re1uired to fluidise the bed by air is 11.77 9a 301.:avitation in a pump creates so many undesirable effects% Sut of the following, which is not an undesirable effect created by cavitation I-:; Cevelops high pressure 302.(or a specific centrifugal air blower operating at constant speed D capacity, the power re1uirement and pressure vary directly as gas density. .
303.
