Description : Pick out the wrong statement. (A) Momentum transfer in laminar flow results from velocity gradient (B) A fluid in equilibrium is not free from shear stress (C) The viscosity of a non-Newtonian fluid is a function of temperature only (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : For laminar flow of Newtonian fluids through a circular pipe, for a given pressure drop and length & diameter of pipe, the velocity of fluid is proportional to (where, μ = fluid viscosity ) (A) μ (B) 1/μ (C) √μ (D) 1/√μ
Last Answer : (B) 1/μ
Description : Consider the following statements in respect of steady laminar flow through a circular pipe: 1. Shear stress is zero on the central axis of the pipe 2. Discharge varies directly with the viscosity of the fluid 3. Velocity is maximum at the ... 2 , 3 & 4 (b) 1 & 3 only (c) 2 & 4 only (d)3 & 4 only
Last Answer : (b) 1 & 3 only
Description : Pressure gradient in the pipe flow is influenced by the (A) Diameter of pipe (B) Velocity of the fluid (C) Density & viscosity of the fluid (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : Pick out the correct statement pertaining to transition/ entrance length in fluid flow. (A) The length of entrance region of pipe, in which full development of fluid flow takes place such that velocity profile does not change ... pipe of diameter 'd' is equal to 50 D (D) All (A), (B) and (C)
Description : Dittus-Boelter equation used for the determination of heat transfer coefficient is valid (A) For fluids in laminar flow (B) For fluids in turbulent flow (C) When Grashoff number is very important (D) For liquid metals
Last Answer : (B) For fluids in turbulent flow
Description : The momentum correction factor for the velocity distribution of laminar flow is (A) 1.3 (B) 1.66 (C) 2.5 (D) None of these
Last Answer : (D) None of these
Description : In turbulent flow, the (A) Fluid particles move in an orderly manner (B) Momentum transfer is on molecular scale only (C) Shear stress is caused more effectively by cohesion than momentum transfer (D) Shear stresses are generally larger than in a similar laminar flow
Last Answer : (D) Shear stresses are generally larger than in a similar laminar flow
Description : Fluid motion in the natural convection heat transfer between a solid surface and a fluid in contact with it, results from the (A) Existence of thermal boundary layer (B) Temperature gradient produced ... difference (C) Buoyancy of the bubbles produced at active nucleation site (D) None of these
Description : Pick out the wrong statement. (A) A fluid mass is free from shearing forces, when it is made to rotate with a uniform velocit (B) Newton's law of viscosity is not applicable to the ... types of bearings (D) Rise of water in capillary tubes reduces with the increasing diameter of capillary tubes
Last Answer : (B) Newton's law of viscosity is not applicable to the turbulent flow of fluid with linear velocity distribution
Description : During agitation of liquids, power consumption during laminar flow is not proportional to the (A) Density of the liquid (B) Viscosity of the liquid (C) Cube of impeller diameters (D) Square of rotational speed
Last Answer : (A) Density of the liquid
Description : Pick out the wrong statement. (A) The shear stress at the pipe (dia = D, length = L) wall in case of laminar flow of Newtonian fluids is (D/4L). ∆p (B) In the equation, T. gc = k. ... to motion (D) With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids
Last Answer : (D) With increase in the Mach number >0.6, the drag co-efficient decreases in case of compressible fluids
Description : For a laminar flow of fluid in a circular tube, 'h1 ' is the convective heat transfer co-efficient at velocity 'V1 '. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is (A) 1.26 h1 (B) 0.794 h1 (C) 0.574 h1 (D) 1.741 h1
Last Answer : (B) 0.794 h1
Description : Transition from laminar flow to turbulent flow in fluid flow through a pipe does not depend upon the (A) Length of the pipe (B) Diameter of the pipe (C) Density of the fluid (D) Velocity of the fluid
Last Answer : (A) Length of the pipe
Description : Isotropic turbulence occurs (A) Where there is no velocity gradient (B) At higher temperatures (C) Only in Newtonian fluids (D) None of these
Last Answer : (A) Where there is no velocity gradient
Description : If the viscosity of ground water is 1.00, the Slitcher's constant is 400, the effective size of soil particles in aquifer is 0.5 mm and hydraulic gradient is 1 in 80, the velocity of flow is (A) 0.25 m/day (B) 0.50 m/day (C) 1.00 m/day (D) 1.25 m/day
Last Answer : Answer: Option D
Description : Transition from laminar flow to turbulent flow is aided by the (A) Surface roughness and curvature (i.e. sharp corners) (B) Vibration (C) Pressure gradient and the compressibility of the flowing medium (D) All (A), (B) & (C)
Last Answer : (D) All (A), (B) & (C)
Description : For laminar flow of a shear thinning liquid in a pipe, if the volumetric flow rate is doubled, the pressure gradient will increase by a factor of (A) 2 (B) < 2 (C) > 2 (D) 1/2
Last Answer : (A) 2
Description : The laminar boundary layer thickness in zero pressure gradient flow over a flat plate along the x-direction varies as x0.5 while the thickness of turbulent boundary layer varies as (where, x = distance from the leading edge) (A) x1.5 (B) x0.8 (C) x-1.5 (D) x-0.8
Last Answer : (B) x0.8
Description : The loss of head due to viscosity for laminar flow in pipes is (where d = Diameter of pipe, l = Length of pipe, v w = Specific weight of the flowing liquid) (A) 4 (B) 8 (C) 16 (D) 32
Description : At the point of boundary layer separation in fluid flow, the (A) Shear stress is maximum (B) Velocity gradient is flat (C) Density variation is maximum (D) Shear stress is zero
Last Answer : Option A
Description : Power required for mixing Newtonian fluids is a function of the (A) Speed of impeller, diameter of impeller & viscosity (B) Density & viscosity of fluid only (C) Density of fluid, viscosity of fluid & impeller dia only (D) None of these
Description : Pick out the correct statement. (A) A forced vortex occurs when fluid rotates as a solid about an axis (B) In laminar flow, Newton's law of viscosity does not apply (C) A free vortex occurs, when fluid rotates as a solid (D) In turbulent flow, there are neither cross-currents nor eddies
Last Answer : (A) A forced vortex occurs when fluid rotates as a solid about an axis
Description : Pick out the wrong statement. (A) The form drag is dependent upon the occurrence of a wake (B) The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent ... of viscosity (D) Existence of the boundary layer in fluid flow is because of viscosity of the fluid
Last Answer : (C) An ideal fluid is the one, which has negligible surface tension and obeys the Newton's law of viscosity
Description : Discharge in laminar flow through a pipe varies (A) As the square of the radius (B) Inversely as the pressure drop (C) Inversely as the viscosity (D) As the square of the diameter
Last Answer : (A) As the square of the radius
Description : In laminar flow through a round tube, the discharge varies (A) Linearly as the viscosity (B) Inversely as the pressure drop (C) Inversely as the viscosity (D) As the square of the radius
Last Answer : (C) Inversely as the viscosity
Description : Which one of the following statements is correct ? (a) Dynamic viscosity is the property of a fluid which is not in motion (b) Surface energy is a fluid property giving rise to the phenomenon ... results from the action of very high pressure (d) Real fluids have lower viscosity than ideal fluids
Last Answer : (d) Real fluids have lower viscosity than ideal fluids
Description : Two fluids are flowing through two similar pipes of the same diameter. The Reynold's number is same. For the same flow rate if the viscosity of a fluid is reduced to half the value of the ... (A) Increase (B) Decrease (C) Remain unchanged (D) Data insufficient to predict relative pressure drop
Last Answer : (B) Decrease
Description : 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
Last Answer : (C) Shear stress and rate of angular deformation in a fluid
Description : Newton's law of viscosity, which states that the shear stress is proportional to the __________ Co-efficient of viscosity is called dynamic or absolute viscosity(where, V = velocity, Vg = velocity gradient). (A) V2 (B) 1/V2 (C) 1/Vg (D) Vg
Last Answer : Option D
Description : Critical velocity in a pipe flow (A) Increases as fluid viscosity increases (B) Increases as pipe diameter increases (C) Independent of fluid density (D) None of these
Last Answer : (B) Increases as pipe diameter increases
Description : Flooding results in (A) High tray efficiency (B) Low tray efficiency (C) High gas velocity (D) Good contact between the fluids
Last Answer : (B) Low tray efficiency
Description : A flow in which the viscosity of fluid is dominating over the inertia force is called (A) Steady flow (B) Unsteady flow (C) Laminar flow (D) Turbulent flow
Last Answer : Answer: Option C
Description : The term "laminar flow" is most often associated with the description of: w) conduction of sound by waves x) current flow in transistors y) effects of viscosity of liquids z) passage of light rays through a liquid
Last Answer : ANSWER: Y -- EFFECTS OF VISCOSITY OF LIQUIDS
Description : Plate towers are preferred to packed towers, when large temperature changes are involved, because of the reason that the (A) Packing may be crushed due to thermal expansion/contraction of the ... C) Viscosity variation of the fluids may cause channelling/flooding (D) None of these
Last Answer : (A) Packing may be crushed due to thermal expansion/contraction of the components of the equipments
Description : Applying 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 (A) Q/2 (B) Q/4 (C) Q/8 (D) Q/16
Last Answer : (D) Q/16
Description : Fluids flow with zero viscosity is called?
Last Answer : Super fluids eg : Honey; Coaltar; Glycerine etc
Description : 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 ... occurs at a radial distance of 0.5 r from the centre of the pipe (r = pipe radius)
Last Answer : (B) Surface of velocity distribution is a paraboloid of revolution, whose volume equals half the volume of circumscribing cylinder
Description : The ratio of average fluid velocity to the maximum velocity in case of laminar flow of a Newtonian fluid in a circular pipe is (A) 0.5 (B) 1 (C) 2 (D) 0.66
Last Answer : (A) 0.5
Description : The kinetic energy correction factor for velocity distribution of laminar flow is (A) 0.5 (B) 1.66 (C) 1 (D) 2
Last Answer : (B) 1.66
Description : The frictional resistance in laminar flow does not depend on the (A) Area of surface in contact (B) Flow velocity (C) Fluid temperature (D) Pressure of flow
Last Answer : (A) Area of surface in contact
Description : What is the ratio of total kinetic energy of fluid passing per second to the value obtained on the basis of average velocity (for laminar flow through a circular pipe)? (A) 0.5 (B) 1 (C) 1.5 (D) 2
Last Answer : (D) 2
Description : The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for __________ fluid. (A) Newtonian (B) Pseudo-plastic (C) Dilatent (D) Bingham plastic
Last Answer : (B) Pseudo-plastic
Description : The fluid velocity varies as the square of the cylindrical pipe diameter, in case of steady state laminar flow at constant pressure drop, for __________ fluid. (A) Newtonian (B) Dilatant (C) Pseudo-plastic (D) Non-Newtonian
Last Answer : (A) Newtonian
Description : The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop of __________ fluid. (A) Dilatent (B) Pseudo-plastic (C) Bingham plastic (D) Newtonian
Last Answer : (A) Dilatent
Description : Pick out the wrong statement. (A) In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed (B) In ... layers over a flat plate are of equal thickness, if Schmidt number is equal to unity
Last Answer : (C) For Laminar flow over a plate of length L, the local mass transfer coefficient at a distance L from the leading edge is 1.5 × 10 -2m/s. Then the average mass transfer co-efficient for the plate is 2 × 10 -2m/s
Description : Convective heat transfer co-efficient in case of fluid flowing in tubes is not affected by the tube length/diameter ratio, if the flow is in the __________ zone. (A) Laminar (B) Transition (C) Both 'a' & 'b' (D) Highly turbulent
Last Answer : (D) Highly turbulent
Description : Maximum heat transfer rate is achieved in __________ flow. (A) Co-current (B) Counter-current (C) Turbulent (D) Laminar
Last Answer : (C) Turbulen
Description : The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are (A) Re.Gz (B) Nu, Pr (C) Nu, Pr, Re (D) Nu, Gz
Last Answer : (D) Nu, Gz
Description : The Graetz number is concerned with the (A) Mass transfer between a gas and a liquid (B) Absorption with chemical reaction (C) Heat transfer in turbulent flow (D) Heat transfer in laminar flow
Last Answer : (D) Heat transfer in laminar flow