7 Fluid Mechanics with Answers PDF

FLUID MECHANICS to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equ...

FLUID MECHANICS to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of SECTION 1 A.relative roughness. B. absolute roughness. 1. The fluid property, due to which, mercury does not wet the glass is C. friction co-efficient for flows at equal Reynold number. A.surface tension D.all (a), (b) & (c). B. viscosity C. cohesion 14. Water hammer in a pipeline results from the D.adhesion A.bursting of pipelines due to closure by a valve. B. rapid pressure change due to a rapid change in the rate of flow. 2. Laminar flow of a Newtonion fluid ceases to exist, when the Reynolds pressure increase due to closure of a valve resulting in decrease in rate of number exceeds C. flow. A.4000 B. 2100 D.none of these. C. 1500 D.3000 15. Molten soap mass is transported by a __________ pump. 3. When the momentum of one fluid is used for moving another fluid, such a A.diaphragm B. reciprocating device is called a/an C. gear D.centrifugal A.jet pump B. blower C. acid egg 16. Which of the following denotes the effect of compressibility in fluid flow? D.none of these A.Weber number B. Mach number 4. The normal stress is the same in all directions at a point in a fluid, when the C. Euler number fluid is D.Reynolds number A.non-viscous. B. incompressible. 17. Nominal size of the discharge pipe of a pump is usually __________ the C. both (a) and (b). nominal size of the inlet pipe. D.having no motion of one fluid layer relative to the other. A.smaller than B. larger than 5. Head developed by a centrifugal pump depends on its C. same as A.speed D.twice B. impeller diameter C. both (a) and (b) 18. The terminal velocity of a small sphere settling in a viscous fluid varies as D.neither (a) nor (b) the A.first power of its dimeter. 6. Hydraulic mean depth (Dm) for a circular pipe of diameter 'D' flowing full is B. inverse of the fluid viscosity. 0.25 D. For a circular channel, at Dm = 0.3 D, gives the condition for the C. inverse square of the diameter. maximum D.square of the difference in specific weights of solid & fluid. A.flow rate B. mean velocity 19. If the discharge of a centrifugal pump is throttled, then its suction lift C. both 'a' & 'b' A.increases D.neither 'a' nor 'b' B. decreases C. remains unchanged 7. The head loss in turbulent flow in a pipe varies D.data insufficient to predict A.as velocity B. as (velocity)2 20. Foot valves provided in pumps are __________ valves. C. inversely as the square of diameter A.relief D.inversely as the velocity B. three/four way C. pressure reducing 8. Most commonly used joint in the underground pipe lines is the D.directional control A.sleevejoint B. coupling 21. At high Reynolds number C. flange A.inertial forces control and viscous forces are unimportant. D.expansion joint B. viscous forces predominate. C. inertial forces are unimportant and viscous forces control. 9. Schedule number of a pipe, which is a measure of its wall thickness, is given D.none of these. by A.1000 P'/S 22. Power loss in an orificemeter is __________ that in a venturimeter. B. 100 P'/S A.less than C. 1000 S/P' B. same as D.10000 P'/S C. more than D.data insufficient, cannot be predicted 10. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the 23. The terminal velocity of a particle moving through a fluid varies as dpn. A.discharge. What is the value of n' for Newton's law regime ? B. suction. A.0.5 B. 1 C. suction minus vapor pressure of the liquid at suction temperature. C. 1.5 D.3 discharge minus vapor pressure of the liquid at the discharge D. temperature. 24. What is the normal range of exit cone angle of a venturimeter ? A.2 to 5 11. With increasing flow rate, the hydraulic efficiency of a centrifugal pump B. 7 to 15 A.monotonically decreases. C. 15 to 25 B. decreases and then increases. D.>25 C. remains constant. D.increases and then decreases. 25. The dimension of dynamic viscosity is A.ML-1T-1 B. L2T-1 12. The velocity profile for turbulent flow through a closed conduit is C. LT-2 D.ML-1T-2 A.logarithmic B. parabolic C. hyperbolic D.linear 26. A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stoke's law. A particle B with diameter 20 13. In case of hydraulically smooth pipe, the resistance to flow depends only on microns settling in the same oil will have a settling velocity the Reynolds number, whereas for a hydraulically rough pipe, the resistance  A.same as that of A. A.40 B. 34 B. one fourth as that of A. C. 8 D.37 C. twice as that of A. D.four times as that of A. 41. Pick out the wrong statement. A.Momentum transfer in laminar flow results from veclocity gradient. 27. The pitot static tube does not measure the __________ pressure. B. A fluid in equilibrium is not free from shear stress. A.static C. The viscosity of a non-Newtonion fluid is a function of temperature only. B. total D.both (b) and (c) C. difference in static & dynamic D.all (a), (b) and (c) 42. Pressure drag does not depend upon the A.roughness of surface of the body. 28. The fluid in which the shearing stress within it is proportional to the B. pressure of main flow only. velocity gradient across the sheared section, is called a __________ fluid. C. length of the body in flow direction. A.Bingham D.all (a), (b) and (c) B. Newtonion C. perfect 43. Dimension of absolute viscosity is D.none of these A.ML-1T-1 B. MLT-1 C. ML-1T D.MLT 29. In fluid flow, cavitation is caused, if the A.fluid velocity decreases to zero. 44. __________ pumps are axial flow pumps. B. total energy decreases. A.Turbine C. both (a) and (b). B. Propeller D.flow pressure approaches its vapor pressure at the prevailing temperature. C. Diffuser D.none of these 30. The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is 45. Brownian movement is prominent in the particle size range of __________ A.0.5 B. 1 microns in case of settling of a particle in a fluid. C. 1.5 D.2 A.2 to 3 B. 0.01 to 0.10 31. The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of C. 200 to 300 the following order of magnitude (assume size of the bacterium to be 1 D.100 to 1000 micron and kinematic viscosity of water to be 10 -6m2/s). A.24000 B. 24 46. For a particle settling in water at its terminal settling velocity, which of the C. 0.24 D.0.44 following is true ? A.Buoyancy = weight + drag 32. For Laminar flow through a packed bed, the pressure drop is proportional to B. Weight = buoyancy + drag (Vs is the superficial liquid velocity and Dp is the particle diameter) C. Drag = buoyancy + weight A.Vs/Dp2 B. Vs2/Dp2 D.Drag = weight C. Vs2/Dp3 D.Vs/Dp3 47. A Bingham fluid of viscosity μ = 10 Pa.s and yield stress, τ0 = 10 KPa, is 33. The maximum delivery pressure of compressors can be upto __________ shared between flat parallel plates separated by a distance of 10 -3 m. The atmospheres. top plate is moving with a velocity of 1 m/s. The shear stress on the plate is A.10 B. 100 A.10 KPa C. 250 D.1000 B. 20 KPa C. 30 KPa 34. Dimension of surface tension is(where, F = force, L = length) D.40 KPa A.FL-1 B. F-1. L 48. Pick out the correct statement. C. F.L-2 A.A forced vortex occurs when fluid rotates as a solid about an axis. D.F-2. L B. In laminar flow, Newton's law of viscosity does not apply. C. A free vortex occurs, when fluidrotates as a solid. 35. Which of the following is not a dimension-less parameter ? D.In turbulent flow, there are neither cross-currents nor eddies. A.Euler number B. Specific gravity 49. Shear stress in a fluid flowing in a round pipe C. Fanning friction factor A.varies parabolically across the cross-section. D.None of these B. remains constant over the cross-section. C. is zero at the centre and varies linearly with the radius. 36. Co-efficient of velocity is __________ the coefficient of discharge. D.is zero at the wall and increases linearly to the centre. A.less than B. more than 50. The resistance wire used in a hot wire anemometer for conducting electrical C. equal to current is made of D.not related to A.copper B. tungsten C. chromium D.aluminium 37. All pipes of a particular nominal size have the same A.inside diameter SECTION 2 B. outside diameter 1. Two-dimensional stream function C. thickness A.relates velocity and pressure. D.none of these B. is constant along a stream line. C. is constant along an equipotential surface. 38. For the transfer of solution of thick slurry, the pump used is a __________ D.none of these. pump. A.reciprocating B. gear 2. What causes cavitation in centrifugal pump ? C. diaphragm D.centrifugal A.High suction pressure B. Low barometric pressure 39. Which of the following is not concerned with the fluid-particle interaction ? C. Low suction pressure A.Drag co-efficient D.High suction velocity B. Froude number C. Galileo number 3. Draining of shallow pits or sump is done by a sump pump, which is a D.Weber number __________ pump. A.single stage vertical 40. Maximum theoretical suction lift for water at 15°C by a centrifugal pump is B. centrifugal 34 ft. The same for water at 90°C will be __________ ft. C. plunger  D.diffuser C. total D.none of these 4. A hydraulic ram acts as a/an __________ pump. A.centrifugal 16. Capacity of a hydraulic accumulator is defined in terms of maximum B. reciprocating A.amount of energy stored. C. impulse B. flow rate through accumulator. D.parallel cylinder C. rate of falling of ram. D.volume available in the cylinder. 5. The ratio of average fluid velocity to the maximum velocity in case of laminar flow of a Newtonion fluid in a circular pipe is 17. Three piping networks as shown in the figure are placed horizontally. They A.0.5 B. 1 are made using identical pipe segments and are subjected to the same C. 2 D.0.66 pressure drop across them. Assuming no pressure losses at junctions, the flow rates across the three networks are related as Q1 : Q2 : Q3. 6. Choose the correct set of dimensions of viscosity that are equivalent (where, F, M, L, T are dimensions for force, mass, length and time respectively). A.FL-2T, ML-1T-1 B. FLT, ML-1T-1 C. ML-1T-3, F-1L2T D.F-1L2T-1, MLT-3 7. The line of action of the buoyant force passes through the centre of gravity of the A.submerged body. B. displaced volume of the fluid. C. volume of fluid vertically above the body. D.horizontal projection of the body. 8. Pick out the wrong statement. The shear stress at the pipe (dia = D, length = L) wall in case of laminar A. A. 1:3: 2 B. 1:2:3 flow of Newtonion fluids is C. 1:2:2 D. 1:2:2 B. 18. With diminishing cross-sectional area in case of subsonic flow in a In the equation, the value of 'n' for converging nozzle, the pseudoplastic and dilatent fluids are < 1 and >1 respectively. A.velocity increases Shear stress for Newtonion fluid is proportional to the rate of shear in the B. pressure decreases C. direction perpendicular to motion. C. both (a) & (b) With increase in the Mach number >0.6, the drag co-efficient decreases in D.neither (a) nor (b) D. case of compressible fluids. 19. Boundary layer separation is characterised by one of the conditions given 9. The friction factor for turbulent flow in a hydraulically smooth pipe below, where 'Re' is the Reynolds number for the flow. Select the A.depends only on Reynolds number. appropriate conditions. B. does not depend on Reynolds number. A.Re > 1, accelerating flow D.none of these. C. Re >1, decelerating flow 10. The pressure at a point in a fluid is not the same in all directions, when the fluid is viscous and 20. Manometers measure the __________ pressure. A.moving B. static A.vacuum as well as the atmospheric C. cold D.hot B. difference in C. absolute D.gage 11. What causes convective acceleration in fluid flow ? A.Steep slope in flow 21. Which of the following fluid forces are not considered in the Navier-Stoke's B. Unsteady nature of flow equation? C. Non-uniformity of flow A.Gravity forces D.Turbulence in flow B. Viscous forces C. Pressure forces 12. The Stoke's stream function applies to the D.Turbulent forces A.irrotational flow only. B. ideal/non-viscous fluids only. 22. Which of the following may be termed as a variable orifice flowmeter ? C. cases of axial symmetry. A.Rotameter D.none of these. B. Pitot tube C. V-notch 13. Slugging in a fluidised bed can be avoided by using D.All (a), (b) and (c) A.tall narrow vessel. B. deep bed of solids. 23. In turbulent flow, a rough pipe has the same friction factor as a smooth pipe C. shallow beds of solids and proper choice of particle size. A.in the zone of complete turbulence. D.very large particles. when the roughness projections are much smaller than the thickness of B. the laminar film. 14. The ratio of width to depth for the most economical rectangular section in C. everywhere in the transition zone. open channel flow is D.when the friction factor is independent of the Reynold's number. A.0.5 B. 1 C. 1.5 D.2 24. Air vessel provided in a reciprocating pump A.smoothens the flow by avoiding pulsations. 15. The simple pitot tube measures the __________ pressure. B. increases the volumetric efficiency of the pump. A.static C. saves the pump from the danger of cavitation. B. dynamic D.none of these.  38. A centrifugal pump loses prime after starting. The reason of this trouble 25. Bernoulli's equation is dependent on the may be A.first law of thermodynamics. A.incomplete priming. B. third law of thermodynamics. B. too high a suction lift. C. law of conservation of momentum. C. low available NPSH and air leaks in the suction pipe. D.none of these. D.all (a), (b), and (c). 26. The capacity of an accumulator is the maximum 39. Venturimeter and orificemeter measures the __________ of the fluid. A.energy which it can store. A.pressure B. discharge which it can deliver. B. maximum velocity C. liquid which it can store. C. average velocity D.none of these. D.point velocity 27. With increase in the temperature, viscosity of a liquid 40. Surge tanks are provided in high pressure water pipelines to A.increases A.store a definte quantity ofwater all the time, B. decreases B. reduce the water hammer. C. remains constant C. facilitate easy dismantling of pipeline for cleaning and maintenance. D.may increase or decrease; depends on the liquid D.none of these. 28. Vena-contracta pressure tapping is at a distance __________ from the 41. Working principle of manometer comprises of balancing a coloumn of position of an orificemeter fitted in a pipe of internal diameter 'd' liquid against the pressure to be measured. Inclined tube manometer is A.d especially used for the measurement of __________ pressure. B. 0.5 d A. small differential C. 2d B. atmospheric D.4d C. absolute D. gage 29. The pump impeller and the turbine runner in a hydraulic torque converter A.have the same diameter. 42. Isotropic turbulence occurs B. have different diameters. A. where there is no velocity gradient. C. are directly coupled. B. at higher temperatures. D.none of these. C. only in Newtonion fluids. D. none of these. 30. Reciprocating pumps compared to centrifugal pumps A.deliver liquid at uniform pressure. 43. The co-efficient of drag and lift for an incompressible fluid depends on the B. can handle slurries more efficiently. A. Reynolds number C. are not subject to air binding. B. Froude number D.can be operated with delivery valve closed. C. Mach number D. all (a), (b) and (c) 31. The fluid property which matters for fall-ing rain drops to acquire spherical shape is its 44. Euler's equation of motion states, that at every point, the A.pressure A. fluid momentum is constant. B. height of descend B. force per unit mass equals acceleration. C. viscosity C. rate of mass outflow is equal to the rate of mass inflow. D.surface tension D. none of these. 32. The simple pitot tube does not measure the 45.The Navier-Stokes equation deals with the law of conservation of A.static pressure. A. mass B. dynamic pressure. B. energy C. velocity at the stagnation point. C. both (a) & (b) D.all (a), (b) and (c). D. momentum 33. Boundary layer separation occurs when the 46. Hydraulic intensifier is used for increasing the A.pressure reaches a minimum. A. rate of velocity of liquid supply. B. cross-section of the channel is reduced. B. rate of flow through delivery pipeline of a pump. C. valve is closed in a pipeline. C. intensity of pressure of the liquid. D.velocity of sound is reached. D. momentum rate through delivery pipe. 34. The head loss in turbulent flow in a pipe varies 47. Which of the following is the 'Blaussius equation', relating friction factor to A.directly as the velocity. the Reynolds number? B. inversely as the square of the velocity. A. f = 0.079.NRe-0.25 C. approximately as the square of the velocity. B. f-0.5 = 4.07 loge (NRef)-0.6 D.inversely as the square of the diameter. 35. For flow through an orifice from a reservoir, the actual velocity at the vena con-tracta is given by A.2gh C. D. none of these B. C.V. 2gh C. Cd 2gh 48. Hydrometer measures the specific gravity of liquids based on the principles D.Cc 2gh of buoyancy. Pycnometer is used to measure the specific gravity of A. powder & grannular solids 36. The ratio of the hydraulic radius to the diameter of the channel, for B. liquids maximum mean velocity of flow in a circular channel, in open channel flow C. low melting point semi-solids is D. all 'a', 'b' & 'c' A.0.3 B. 0.9 C. 0.03 D.0.66 49. Euler's equation of motion is a statement expressing A. conservation of mass. 37. For the free settling of a spherical particle through a fluid, the slope of, C D- B. conservation of energy. log NRe , plot is C. Newton's first law of motion. A.1 B. -1 D. Newton's second law of motion. C. 0.5 D.-0.5 50. During ageing of fluid carrying pipes, the  A. pipe becomes smoother with use. B. union B. friction factor increases linearly with time. C. tee C. absolute roughness decreases with time. D. none of these. D. absolute roughness increases linearly with time. 10. In case of a centrifugal pump, the ratio of total delivered pressure to SECTION 3 pressure developed with the impeller is called the __________ efficiency. 1. Pick out the wrong statement. A. manometric A. The form drag is dependent upon the occurrence of a wake. B. mechanical B. The shear stress at any given cross-section of a pipe for steady flow C. volumetric (either laminar or turbulent) varies linearly as the radial distance. D. overall C. An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity. 11. Acceleration head in a reciprocating pump D. Existence of the boundary layer in fluid flow is because of viscosity A. increases the work done during delivery stroke. of the fluid. B. decreases the work done during suction stroke. C. does not change the work requirement of the pump. 2. Mass velocity is independent of temperature & pressure, when the flow is D. increases the work done during suction stroke. A. unsteady through unchanged cross-section. B. steady through changing cross-section. 12. The ratio of inertial forces to elastic forces is called the __________ C. steady and the cross-section is unchanged. number. D. unsteady and the cross-section is changed. A. Reynolds B. Mach 3. Very small pressure difference (< 5 mm water coloumn) can be most C. Euler conveniently measured by a/an __________ manometer. D. Weber A. U-tube water. B. U-tube mercury. 13. The equivalent diameter for flow through a rectangular duct of width B and C. inclined tube mercury. height H is D. inclined tube water. 4. For pipe flows, head is proportional to __________ at constant capacity(where, D = pipe diameter). A. A. 1/D B. 1/D2 C. 1/D5 D. D2 B. 5. For a given Reynold number as d/D for an orifice increases, Cd will (where, d & D are orifice & pipe diameters respectively). A. increase C. a B. decrease C. remain constant D. either (a) or (b); depends on other factors D. 6. The energy equation, (E = 14. Fluid flow at increasing rate through a diverging pipe is an example of __________ flow. A. steady uniform internal energy/mass), is applicable to B. non-steady uniform A. perfect gases only. C. steady non-uniform B. isothermal flow of gases. D. non-steady non-uniform C. adiabatic unsteady flow of gases. D. all compressible fluids. 15. The temperature in isentropic flow A. does not depend on Mach number. 7. What is the ratio of fluid carrying capacity of two pipes having B. depends on Mach number only. diameters d1 and d2 respectively? C. cannot drop and then increase again downstream. D. none of these. 16. A fluid element has a velocity V = -y2. xi + 2yx2. j. The motion at (x, y) = A. (l/2, 1) is A. rotational and incompressible B. rotational and compressible C. irrotational and compressible D. irrotational and incompressible B. A 17. Check in a centrifugal pump is A. provided in the discharge line. B. generally a globe valve. C. provided to prevent liquid from backing up through the pump when C. the pump is turned off or accidently stops running. D. all (a), (b) and (c). 18. Drag force acting on a body does not depend upon the D. A. density of the fluid. B. density of the body. 8. A differential pressure cell is used for C. velocity of the body. A. measuring small pressure difference in gases. D. projected area of the body. B. measuring small pressure difference in liquids. C. remote recording of pressure difference. 19. Centrifugal pump is normally classified on the basis of the D. measuring the difference of the impact & the static pressure. A. rpm. B. type of casing. 9. If more than two branches of pipes are to be connected at the same point, C. impeller blade angle. then use a/an D. number of blades in impeller. A. elbow 20. Where does the maximum stress occur in case of laminar flow of C. 0 incompressible fluid in a closed conduit of diameter 'd'? D. 5 A. At the centre B. At d/4 from the wall 31. A mono pump is a __________ pump. C. At the wall A. centrifugal D. At d/8 from the wall B. piston C. positive acting rotary 21. In case of isentropic flow, the speed of sound in an ideal gas is proportional D. a group of vacuum to (where, T = absolute temperature ) 32. Higher specific speed (200-500) of a centrifugal pump indicates that the pump is of __________ flow type. A. B. 1/T A. axial B. radial C. mixed C. D. none of these D. T 33. The variable required to be known in correlations used for estimating the 22. Applying a pressure drop across a capillary results in a volumetric flow rate horse power of a centrifugal gas compressor and hence its cost are 'Q' under laminar flow conditions. The flow rate for the same pressure drop, in P. Inlet pressure Q. Compressor rpm a capillary of the same length but half the radius is R. Delivery pressure S. Volumetric flow rate at inlet. A. Q/2 A. P, Q and R B. Q/4 B. P and R C. Q/8 C. R and S D. Q/16 D. P, Rand S 23. Cd, Cc and Cv are related (for flow through an orifice) as (where, Cd = 34. Theoretical head developed by a centrifugal pump does not depend upon discharge co-efficient the __________ the impeller. Cc = co-efficient of contraction A. radius of B. speed of C. fluid velocity leaving D. none of these Cv = co-efficient of velocity 35. An ideal fluid is A. non-viscous B. incompressible ) C. both (a) & (b) A. Cd = Cc/Cv D. neither (a) & (b) B. Cd = Cc.Cv C. Cd = Cv/cc 36. Pick out the Hagen-Poiseulle's equation. D. none of these 24. In an incompressible fluid, the density is A. greatly affected by moderate changes in pressure. A. B. greatly affected only by moderate changes in temperature. C. not affected with moderate change in temperature & pressure. D. sensible to changes in both temperature & pressure. B. 25.Check valves are used A. at high pressure. B. in bends. C. for controlling water flow. D. for unidirectional flow. C. 26. Velocity distribution for flow between two fixed parallel plates A. varies parabolically across the section. B. is constant over the entire cross-section. D. C. is zero at the plates and increases linearly to the midplane. D. none of these. 37. In case of isentropic flow, the speed of sound in an ideal gas is proportional to (where M = molecular weight of the gas) 27. Priming is needed in a __________ pump. A. reciprocating B. gear A. C. centrifugal D. diaphragm B. C. 1/M 28. An ideal nozzle design aims at D. M A. minimising wall friction. B. suppressing boundary layer separation. 38. Boundary layer separation is caused by the C. both (a) & (b). A. reduction of pressure to vapour pressure. D. neither (a) nor (b). B. boundary layer thickness reducing to zero. C. adverse pressure gradient. 29. Which of the fluid forces are not considered in the Reynold's equation of D. reduction of pressure gradient to zero. flow ? A. Viscous forces B. Turbulent forces C. Pressure forces D. Compressibility forces 39. With increase in temperature, the vapor pressure of liquids A. increases 30. For ideally incompressible fluid, the Mach number will be B. increases linearly A. 1.5 C. decreases B. 1 D. remains constant 40. A mercury (specific gravity = 13.6) manometer connected across an D. none of these orificemeter fitted in a pipe shows a manometer reading of 2 cms. If the manometer liquid is changed to carbon tetrachloride (specific gravity = 1.6), 2. In a fluidised bed reactor then for the same flow rate of water the new manometer reading will be A. temperature gradients are very high. __________ cms. B. temperature is more or less uniform. A. 17 C. hot spots are formed. B. 42 D. segregation of the solids occurs. C. 84 D. 1.8 3. The flow of a liquid through tapering pipe at a constant rate is an example of __________ flow. 41. The ratio of wall drag to total drag in the Stoke's law range is A. steady uniform A. 0.5 B. steady non uniform B. 1 C. unsteady uniform C. 1/3 D. unsteady non uniform D. 2/3 4. Pick out the correct statement pertaining to transition/ entrance length in 42. Rotary vacuum pumps can reduce the absolute pressure to as low as fluid flow. __________ mm Hg. A. The length of entrance region of pipe, in which full development of A. 1 fluid flow takes place such that velocity profile does not change B. 0.1 downstream, is called the transition length. C. 0.01 B. Transition length for laminar flow of Newtonion fluids in a pipe of D. 0.001 diameter 'd' is equal to 0.05. D.NRe. C. Transition length for turbulent flow of Newtonion fluids in a smooth 43. A pitched-blade turbine draws __________ a straight blade turbine. pipe of diameter 'd' is equal to 50 D. A. less power than D. all (a), (b) and (c). B. more power than C. same power as 5. A perfect gas D. data insufficient to predict A. does not satisfy PV= nRT. B. is incompressible and has zero viscosity. 44. The most suitable flow measuring device for the fluid flow measurement in C. has constant specific heat. a very large diameter pipeline is a D. can't develop shear stresses. A. weir B. pitot tube 6. In a/an __________ , the flow rate of fluids is obtained by measuring the C. Kennison nozzle difference between the impact and the static pressure. D. V-notch A. rotameter B. pitot tube 45. A centrifugal pump is called a turbine pump, if it is having a C. venturimeter A. turbine type impeller. D. flow nozzle B. vaned diffusion casing. C. rotating vaned volute. 7. During fluid flow, variation of shear stress(τ) with velocity D. none of these. gradientat constant pressure temperature is shown below in the figure 46. Remote control valve is a __________ valve. A. gate B. butterfly C. needle D. globe 47. Which of the following quantities are computed by using the hydraulic radius for non-circular ducts ? A. Velocity and relative roughness. B. Head loss and velocity. C. Reynold number, relative roughness and head loss. D. Reynolds number and friction factor. 48. Centre of pressure in an immersed body is __________ the centre of gravity. A. above B. below In the above figure, Binghom plastic is represented by the curve. C. at A. V D. either above or below; depends on the liquid density B. II C. III 49. The centre of pressure is D. I A. always below the centroid of the area. B. always above the centroid of the area. 8. Speed of sound in an ideal gas depends on its C. a point on the line of action of the resultant force. A. temperature D. at the centroid of the submerged area. B. pressure C. specific volume 50. The uniformity of a gas fluidised bed depends upon the __________ of the D. none of these solid particles. A. size 9. A centrifugal pump designed for handling water (μ = 1 cp) will deliver B. surface properties __________ when pumping a thicker oil (μ = 30 cp). C. both (a) and (b) A. less head & capacity D. neither (a) nor (b) B. more head C. more capacity D. less head & more capacity SECTION 4. 10. If 'x' is the depth of flow in an open channel of large width, then the 1. Pascal law is not applicable for a/an __________ fluid. hydraulic radius is equal to A. accelerating frictionless A. x B. static B. x/2 C. uniformly moving C. x/3  D. 2x/3 A. Venturimeter B. Orifice meter 11. In fluid flow, the boundary layer separation can not occur C. Rotameter A. in case of boundaries experiencing form drag. D. Flow nozzle B. at points of abrupt changes in the flow directions. C. in laminar flow. 23. When the water is warm, the height to which it can be lifted by a pump D. none of these. A. decreases due to reduced viscosity. B. decreases due to reduced vapour pressure. 12. For a given fluid flow rate, which of the following incurs maximum head C. increases due to increased vapour pressure loss ? D. decreases due to increased frictional resistance. A. Orifice meter B. Venturimeter 24. Pipes having diameter 14 inches or more are designated by their C. Flow nozzle A. outside diameter D. All of them incur the same head loss B. inside diameter C. schedule number 13. Which of the following assumptions enables the Euler's equation of motion D. none of these to be integrated ? A. The fluid is incompressible. 25. Viscosity of water at 40°C lies in the range of B. The fluid is non-viscous. A. 1 x 10-3 to 2 x 10-3 kg/m.s C. The continuity equation is satisfied. B. 0.5 x 10-3 to 1 x 10-3 kg/m.s D. The flow is rotational and incompressible. C. 1 to 2 kg/m.s D. 0.5 to 1 kg/m.s 14. In case of a pipe exit fitted with a nozzle, the A. conversion of kinetic head to pressure head is facilitated. 26. A centrifugal pump has the following specifications: B. conversion of pressure head to kinetic head is facilitated. Power = 4 H.P.; Speed = 800 rpm C. power transmitted through the nozzle is maximum, when the head Head = 8 metres lost due to friction in the pipe is equal to one third of the total supply Flow = 1000 litres/minutes. head. If its speed is halved, the new discharge will be __________ litres/minute. D. both (b) and (c) A. 500 B. 200 15. A fluid whose apparent viscosity increases with shear rate is termed as the C. 1000 __________ fluid. D. 750 A. Newtonion B. viscous 27. The dimension of kinematic viscosity is C. dilatant A. ML-2T-1 D. non-viscous B. L2T-1 C. ML-2T-2 16. Which of the following is the most common pump for pumping either raw D. none of these sewage or sludge ? A. Electromagnetic pump 28. A pipe of I.D. 4 m is bifurcated into two pipes of I.D. 2 m each. If the B. Centrifugal pump average velocity of water flowing through the main pipe is 5 m/sec, the average C. Reciprocating pump velocity through the bifurcated pipes is D. Gear pump A. 20 m/sec B. 10 m/sec 17. Transition length for a turbulent fluid entering into a pipe is around C. 52 m/sec __________ times the pipe diameter. D. 5 m/sec A. 5 B. 50 29. Turbulent flow generally occurs for cases involving C. 500 A. highly viscous fluid D. 1000 B. very narrow passages C. very slow motion 18. For turbulent flow of an incompressible fluid through a pipe, the flow rate D. none of these Q is proportional to (Δ P)n, where ΔP is the pressure drop. The value of exponent 'n' is 30. Lower BWG means __________ of the tube. A. 1 A. lower thickness B. 0 B. lower cross-section C. < 1 C. outer diameter D. > 1 D. inner diameter 19. Reciprocating pumps are not able to compete with the centrifugal pump for 31. For laminar flow of Newtonion fluid in a circular pipe, the velocity industrial use, mainly because these pumps have distribution is a function of the distance 'd' measured from the centre line of the A. very low speeds. pipe, and it follows a __________ relationship. B. smaller discharge. A. logarithmic C. higher capital &maintenance cost. B. parabolic D. high vibrations. C. hyperbolic D. linear 20. Which is the correct relationship for a centrifugal pump ? (where, D = Impeller diameter, inches H = Head developed, ft of liquid pumped N = Speed 32. The Prandtl mixing length is of pump, rpm) A. zero at the pipe wall and is a universal constant. A. D = 1840 H0.5/N B. independent of radial distance from the pipe axis. B. D = 1840 N/H0.5 C. independent of the shear stress. C. H = 1840 D0.5/N D. useful for computing laminar flow problems. D. D = 1840 H/N 33. N2Re/NFr is called the __________ number. 21. Which of the following pipe bends will incur the largest head loss ? A. Brinkman A. U-bend B. Galileo B. 30° bend C. Archimedes C. 45° bend D. Euler D. 90° bend 34. The location of centre of pressure, which defines the point of application of 22. Which is the most efficient and best for measuring very small flow rate of the total pressure force on the surface, can be calculated by applying the gases ? principle of moments according to which "sum of the moment of the resultant force about an axis is equal to the sum of the components about the same axis". 43. A venturimeter can not be used for the direct measurement of The centre of pressure of a rectangular surface (of width 'w') immersed A. datum difference in the stretch of pipeflow vertically in a static mass of fluid is at a depth of(where, y = depth of the liquid) B. pressure difference in the flow throughpipeline. C. friction loss in pipe flow. D. all (a), (b) and (c). A. 44. A double acting reciprocating pump compared to a single acting pump (of B. 2y/3 almost same size working under same pressure levels) would give almost double A. head B. discharge C. C. efficiency D. 3y/4 D. none of these 35. As the velocity V and thus the Reynolds number of a flow past a sphere 45. Which of the following is used for very accurate measurement of flow of increases from very low value, the drag force for Re 1 B. O.D. D. 2 C. thickness D. none of these 17. The general relationship between speed N, head H, power P and discharge Q for a centrifugal pump is 7. Transition from laminar flow to turbulent flow is aided by the A. Q∝N : H∝N2 : P∝N3 A. surface roughness and curvature (i.e.sharp corners). B. Q∝N2 : H∝N3 : P∝N B. vibration. C. Q∝N : H∝N3 : P∝N2 C. pressure gradient and the compressibility of the flowing medium. D. Q∝N3 : H∝N : P∝N2 D. all (a), (b) & (c). 18. What is the ratio of the velocity at the axis of the pipe to the mean velocity 8. For flow of fluids through packed bed, the superficial velocity is of flow in case of pipe flow under viscous condition ? A. less than the average velocity through channels. A. 0.5 B. more than the average velocity through channels. B. 0.67 C. dependent on the pressure drop across the bed. C. 1 D. same as the average velocity through channels. D. 2 9. Cd is always __________ Cc. 19. Foot valve provided in the pump is a __________ valve. A. greater than A. direction control B. less than B. back pressure C. equal to C. relief D. either more or less than D. pressure reduction 20. The discharge co-efficient for an orificemeter does not depend upon the A. pipe length. B. ratio of pipe diameter to orifice diameter. 10. Buoyant force C. type of orifice & the Reynolds number. A. for non-symmetrical bodies is not vertical. D. pipe diameter. B. depends on the depth of the submergence of the floating body. C. depends on the weight of the floating body. 21. Which of the following options will facilitate the achievement of a very D. none of these. high head (say 30 metres) in case of a centrifugal pump? A. Increasing the impeller speed and the volute area. 11. Which of the following is an undesirable property of a manometric liquid ? B. Increasing the number of vanes in the impeller. A. Non-sticky & non-corrosive nature. C. Mounting of two or more impellers in series on a single shaft. B. High vapour pressure. D. Either of (a), (b) or (c). C. Low viscosity & surface tension. D. Low co-efficient of thermal expansion. 22. An equipotential line is __________ to the velocity vector at every point. A. normal 12. Characteristic curves for a centrifugal pump plotted against its capacity is B. abnormal shown in the diagram. x, y and z denote respectively C. tangential D. none of these 23. Specific speed for a centrifugal pump is A. A. efficiency, head and B.H.P. B. B. head, efficiency and B.H.P. C. B.H.P., efficiency and head D. efficiency, B.H.P. and head C. 13. Liquid delivery by centrifugal pump starts, only when the head developed by it is equal to the __________ head. A. manometric B. total D. 24.Path followed by water jet issuing from the bottom of a water tank will be a 35. In the low Reynolds number region, the drag force on a sphere is A. parabola (vertex being at the opening). proportional to B. hyperbola. A. V C. horizontal straight line. B. V2 D. zig-zag path (which is geometrically undefined). C. V4 D. V0.5 25. Which of the following produces maximum pressure difference for transportation of gases ? 36. The continuity equation A. Vaccum pumps A. is independent of the compressibility of the fluid. B. Blowers B. is dependent upon the viscosity of the fluid. C. Fans C. represents the conservation of mass. D. Compressors D. none of these. 26. For flow through a venturi at a particular discharge, the correct 37. Experimental study of laminar fluid flow through a circular tube was relationships among velocities at point X, Y and Z would be conducted by A. Reynolds B. Hagen and Poiseuille C. Pascal D. Blake-Plummer 38. The most economical flow control valve for use with large diameter pipes is a A. butterfly valve A. V1 < V2 < V3 B. globe valve B. V2 > V1 and V2 > V3 C. needle valve C. V1 > V2 > V3 D. none of these D. none of these. 39. Each term in Bernaulli's equation represents the __________ of the fluid. 27. Drag co-efficient in hindered settling is __________ that in free settling. A. energy per unit mass A. less than B. energy per unit weight B. equal to C. force per unit mass C. not necessarily greater than D. none of these D. always greater than 40. Which of the following is a dimensionless parameter ? 28. Efficiency of power transmission (η) through a circular pipe is given by A. Angular velocity (ht - hf)/ht, which has a maximum value of __________ percent. B. Specific weight A. 33:3 C. Kinematic viscosity B. 50 D. None of these C. 66.6 D. 88.8 41. If the head over the triangular notch is doubled, the discharge will increase by __________ times. 29. One dimensional fluid flow implies the A. 2 A. flow in straight lines only. B. 2.828 B. uniform flow. C. 5.657 C. steady uniform flow. D. 4 D. flow in which transverse components are zero. 42. Friction factor for a hydraulically smooth pipe at NRe = 2100 is f1. If the 30.__________ forces act on a particle moving through a stationary fluid. pipe is further smoothened (i.e., roughness is reduced), the friction factor at the A. Gravity same value of NRe, will B. Drag A. increase. C. Buoyant B. decrease. D. all (a), (b), & (c) C. remain unchanged. D. increase or decrease depending on the pipe material. 31. In frictional fluid flow, the quantity, , is 43. What is the force required (in Newtons) to hold a spherical balloon stationary in water at a depth of H from the air-water iterface? The balloon is of A. constant along a streamline. radius 0.1 m and is filled with air. B. not constant along a streamline. C. increased in the direction of flow. D. none of these. A. 32. Hydraulic radius is the ratio of A. wetted perimeter to flow area. B. flow area to wetted perimeter. B. C. flow area to square of wetted perimeter. D. square root of flow area to wetted perimeter. 33. The unit of bulk modulus of elasticity for a liquid in S.I. unit is C. A. N B. N/m C. N/m2 D. N/m3 D. 44. For the laminar flow of a fluid in a circular pipe of radius R, the Hagen- 34. Power requirement of fans having constant wheel diameter varies Poisseule equation predicts the volumetric flow rate to be proportional to __________ fan speed. A. R A. as square of B. R2 B. directly as C. R4 C. as cube of D. R0.5 D. none of these 45. Interstage coolers are provided in a multistage compressor to A. save power in compressing a given volume to a given pressure.  B. cool the delivered air. D. gravitational stress to drag stress. C. achieve the exact delivery pressure. D. none of these. 6. The momentum correction factor for the velocity distribution of laminar flow is 46. Consider a centrifugal pump having a specific impeller diameter, fixed A. 1.3 impeller speed pumping a liquid of constant density at a particular discharge B. 1.66 capacity. With decrease in the capacity of the pump, the __________ decreases. C. 2.5 A. NPSH required. D. none of these B. BHP required by the pump. C. head of the liquid pumped. 7.For the same flow rate of a fluid, the pressure drop is the least for D. all (a), (b) and (c). A. venturimeter B. orificemeter 47.Reynolds number is the ratio of C. flow-nozzle A. viscous forces to gravity forces. D. Δp is same for all B. inertial forces to viscous forces. C. viscous forces to inertial forces. 8.The valve commonly used in pipes larger than 2" dia is a D. inertial forces to gravity forces. A. globe valve B. plug-cock C. gate valve D. check valve 48. For the manometer set up shown in the figure, the pressure 9.Foot valves are provided in the suction line of a centrifugal pump to difference PA - PB is given by A. avoid priming, every time we start the pump. B. remove the contaminant present in the liquid. C. minimise the fluctuation in discharge. D. control the liquid discharge. 10.An ideal fluid is A. frictionless & incompressible. B. one, which obeys Newton's law of viscosity. C. highly viscous. D. none of these. A. (ρH - ρair)gH 11. In area meter (e.g., rotameter), with increase in the fluid flow rate, the B. (ρH - ρL)gH A. pressure drop increases linearly. C. (ρH - ρL) gH + (ρL - ρair). g(L - H) B. pressure drop is almost constant. D. (ρH - ρL) gL + (ρL - ρair)Gh C. area through which fluid flows does not vary. D. none of these. 49.The discharge through a venturimeter depends upon A. pressure drop only. 12. Drag co-officient CD, in Stoke's law range is given by B. its orientation. C. co-efficient of contraction only. D. none of these. A. 50.N. second/m2 is A. the S.I. unit of dynamic viscosity. B. the S.I. unit of kinematic viscosity. C. equivalent to one poise. B. D. equivalent to one stoke. SECTION 6 1. The distance between metacentre and __________ is called metacentric C. height. A. water surface B. centre of gravity C. centre of buoyancy D. none of these D. 2. Check valve is used for __________ flow. A. very precise control of B. unidirectional C. multidirectional 13. In power law, , then the fluid is D. none of these A. Newtonian B. dilatant 3. Capacity of a rotary gear pump can be varied by C. thixotropic A. changing the speed of rotation. D. rheopectic B. bleeding air into suction. C. bypassing liquid from the suction or discharge line. 14.The buoyant force acting on a floating body is dependent on the D. all (a), (6) and (c). A. viscosity of the liquid. B. weight of the liquid displaced. 4. For a given Reynolds number, in a hydraulically smooth pipe, further C. depth of immersion of the body. smoothening __________ the friction factor. D. surface tension of the liquid. A. brings about no further reduction of B. increases 15. A Newtonion fluid is that C. decreases A. which follows Newton's law of motion. D. none of these B. which needs a minimum shear, before it starts deforming. C. for which shear & deformation are related as 5. Power number is the ratio of A. drag stress to inertial stress. D. none of these. B. inertial stress to drag stress. C. inertial stress to gravitational stress. 16. In case of end to end connection of two or more pipes in series, the B. centre of gravity of a submerged body. __________ each pipe. C. centroid of the volume of any floating body. A. same rate of flow passes through D. none of these. B. head loss is same through C. rate of flow in each pipe is proportional to the length of 29. Cavitation in a centrifugal pump can be avoided by keeping the D. total flow rate is the sum of flow rate in A. inlet pressure high B. outlet pressure low 17. Which of the following equations applies to the fluid flow through a packed C. inlet pressure low bed for very large Reynolds number ? D. outlet pressure high A. Fanning equation B. Blake-Pllummer equation 30. Vane anemometer C. Hagen-Poiseulle equation A. is an area meter. D. Kozney-Karman equation B. is a variable head meter. C. rotates an element at a speed determined by the velocity of the 18. The flow of gas along a pipe in the direction of decreasing pressure causes fluid in which the meter is immersed. decrease in its D. none of these. A. viscosity B. specific volume 31. The peripherial velocity at inlet of a centrifugal pump having inlet diameter C. velocity of 25 cms and rotating at 950 rpm is __________ m/sec. D. none of these A. 1.8 B. 12.4 19. Centrifugal pump can't be used to pump C. 186.2 A. molten sodium (used as a coolant in Fast Breeder Reactor). D. 736.4 B. moderately viscous vegetable oil used in soap industry. C. thick molten soap at 80°C. D. none of the above. 32. Laminar flow is characterised by the nonexistence of A. pressure fluctuation. 20. A stream line is B. eddies. A. fixed in space in steady flow. C. deviating velocities. B. always the path of particle. D. all (a), (b)&(c). C. drawn normal to the velocity vector at every point. D. a line connecting the mid points of flow cross-section. 33. 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 21. Quicksand is an example of a __________ fluid. __________ length. A. bingham plastic A. equivalent B. dilatent B. transition C. Newtonion C. Prandtl mixing D. Pseudoplastic D. none of these 22. Correction for capillary effect in manometers (used for pressure 34. Select the correct practical example of steady non-uniform flow. measurement) need not be applied, if diameter of the manometer tube is A. Motion of water around a ship in a lake. __________ mm. B. Motion of river around bridge piers. A. < 4 C. Steadily decreasing flow through a reducing section. B. > 4 D. Steadily increasing flow through a pipe. C. > 12.5 D. < 10 35. Hydraulic diameter for non-circular ducts is equal to __________ times the area of flow divided by the perimeter. 23. Differential manometer measures the A. two A. absolute pressure B. three B. gauge pressure C. four C. pressure difference D. eight D. pressure gradient 36. Terminal velocity is 24. The pressure and power requirement of a gas fan at constant speed & A. a constant velocity with no acceleration. capacity varies __________ the gas density. B. a fluctuating velocity. A. directly as C. attained after moving one-half of total distance. B. inversely as square root of D. none of these. C. inversely as D. as square of 37.Consider two pipes of same length and diameter through which water is passed at the same velocity. The friction factor for rough pipe is f 1 and that for 25. Isothermal turbulent flow of a fluid results in decrease of its pressure, which smooth pipe is f2. Pick out the correct statement. depends on the A. f1 = f2 A. wall roughness. B. f1 < f2 B. Reynolds number. C. f1 > f2 C. both (a) & (b). D. data not sufficient to relate f1 & f2 D. neither (a) nor (b). 38. For an incompressible fluid, the bulk modulus of elasticity is 26. Boundary layer thickness in laminar flow over a flat plate increases A. 5 kg/m3 as(where, d = distance from the leading edge.) B. ∞ N/m2 A. square root of d C. 1 N B. d1/3 D. 0 N/m C. d2 D. d2/3 39.A fluid is a substance, that A. has to be kept in a closed container. 27. Gradually varied flow in open channel is a/an __________ flow. B. is almost incompressible. A. steady uniform C. has zero shear stress. B. steady non-uniform D. flows when even a small shear is applied to it. C. unsteady uniform D. unsteady non-uniform 40. The pressure intensity is the same in all directions at a point in a fluid A. only when the fluid is frictionless. 28. The line of action of the buoyant force acts through the B. only when the fluid is at rest having zero velocity. A. centroid of the displaced volume of fluid.  C. when there is no motion of one fluid layer relative to an adjacent 2. The dimension of surface tension is layer. a. ML-2 D. regardless of the motion of one fluid layer relative to an adjacent b. MT-2 layer. c. MLT-2 d. ML-2T 41. Which of the following must be followed by the flow of a fluid (real or ideal)? 3. Pick out the correct statement. (I) Newton's law of viscosity. a. Fanning friction factor is inversely proportional to Reynolds number (II) Newton's second law of motion. always. (III) The continuity equation. b. The property of a randomly packed bed (with raschig rings) is given (IV) Velocity of boundary layer must be zero relative to boundary. by the ratio of the total volume to the volume of voids in the bed. (V) Fluid cannot penetrate a boundary. c. Mach number in an incompressible fluid is always unity. A. I, II, III d. Mach number is given by the ratio of the speed of the fluid to B. II, III, V that of sound in the fluid under conditions of flow. C. I, II, V D. II, IV, V 4. The friction factor is a. always inversely proportional to the Reynolds number. 42. Mach number is defined as the ratio of the local flow velocity to the sonic b. not dimensionless. velocity in the fluid. For what value of Mach number, the gases are considered c. not dependent on the roughness of the pipe. incompressible ? d. none of these A. < 0.3 B. > 3 5. Rubber latex is an example of a __________.fluid. C. 50