Description : The major reason of hydrodynamic noise (i.e., noise resulting from liquid flow) is (A) Pipe vibrations (B) Cavitation (C) Boundary layer separation (D) Fluctuation in liquid flow
Last Answer : (B) Cavitation
Description : For flow over a flat plate, the ratio of thermal boundary layer thickness, 'xt' and hydrodynamic boundary layer thickness 'x' is equal to (where, NPr = Prandtl number) (A) NPr (B) NPr 1/3 (C) NPr -1 (D) NPr -1/3
Last Answer : (B) NPr 1/3
Description : Boundary layer separation is caused by the (A) Reduction of pressure to vapour pressure (B) Boundary layer thickness reducing to zero (C) Adverse pressure gradient (D) Reduction of pressure gradient to zero
Last Answer : (D) Reduction of pressure gradient to zero
Description : Boundary layer separation is caused by the (A) Reduction of pressure below vapour pressure (B) Reduction of pressure gradient to zero (C) Adverse pressure gradient (D) Reduction of boundary layer thickness to zero
Last Answer : (C) Adverse pressure gradient
Description : How the thickness of thermal boundary layer and thickness of hydrodynamic boundary layer related ?
Last Answer : Ratio of their thickness = (Prandtl number)-1/3.
Description : Thickness of thermal boundary layer is more compared to that of hydrodynamic boundary layer, when the value of Prandtl number is (A) 1 (B) < 1 (C) > 1 (D) > 5
Last Answer : (B) < 1
Description : . If Prandtl number is greater than the Schmidt number, then the (A) Thermal boundary layer lies inside the concentration boundary layer (B) Concentration boundary layer lies inside the thermal boundary ... (D) Hydrodynamic (i.e., momentum) boundary layer is thicker than the other two
Last Answer : (A) Thermal boundary layer lies inside the concentration boundary layer
Description : The ratio of hydrodynamic boundary layer to thermal boundary layer thickness in case of liquid metals is (A) < 1 (B) 1 (C) > 1 (D) 2
Last Answer : (A) < 1
Description : Boundary layer separation occurs when the (A) Pressure reaches a minimum (B) Cross-section of the channel is reduced (C) Valve is closed in a pipeline (D) Velocity of sound is reached
Last Answer : (B) Cross-section of the channel is reduced
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 : 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 : 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 : 02. A flow in which each liquid particle does not have a definite path and the paths of individual particles also cross each other is called turbulent flow. A) Agree B) Disagree
Last Answer : A
Description : A journal bearing with hydrodynamic lubrication is running steadily with a certain amount of minimum film thickness. When the load and speed are doubled, how does the minimum film thickness vary? [IES-2008 ... Gets reduced to one-fourth of original value (d) Gets reduced to half of original value
Last Answer : (a) Remains unchanged
Description : The thermal boundary layer at NPr > 1 (A) Is thicker than hydrodynamic boundary layer (B) Is thinner than hydrodynamic boundary layer (C) And the hydrodynamic boundary layers are identical (D) Disappears
Last Answer : (B) Is thinner than hydrodynamic boundary layer
Description : Boundary layer separation is characterised by one of the conditions given below, where 'Re' is the Reynolds number for the flow. Select the appropriate conditions. (A) Re > 1, accelerating flow (C) Re >1, decelerating flow
Last Answer : (D) Re >>1, decelerating flow
Description : In fluid flow, the boundary layer separation cannot occur (A) In case of boundaries experiencing form drag (B) At points of abrupt changes in the flow directions (C) In laminar flow (D) None of theseIn ... B) At points of abrupt changes in the flow directions (C) In laminar flow (D) None of these
Last Answer : (D) None of these
Description : For flow past a flat plate, if ‘x’ is the distance along the plate in the direction of flow, the boundary layer thickness is proportional to (A) √x (B) 1/√x (C) x (D) 1/x Answe
Last Answer : (A) √x
Description : Pick out the wrong statement: (A) Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer (B) Blowers develop a maximum pressure of 2 atmospheres ( ... factor in case of turbulent flow of liquids in pipe depends upon relative roughness & Reynolds number
Last Answer : (C) Friction losses in pipe fittings are generally expressed in terms of velocity heads
Description : In a boundary layer developed along the flow, the pressure decreases in the downstream direction. The boundary layer thickness in this case will (A) Decrease gradually (B) Increase gradually (C) Increase rapidly (D) Remain constant
Last Answer : (B) Increase gradually
Description : The region between the separation streamline and the boundary surface of the solid body is known as (A) Wake (B) Drag (C) Lift (D) Boundary layer
Last Answer : Answer: Option A
Description : The thickness of a laminar boundary layer over a flat plate at two different sections P and Q are 0.8 cm and 2.4 cm respectively. If the section Q is 3.6 m downstream of P, the distance of section P from the leading edge of the plate is (a) 0.32 m (b) 0.22 m (c) 0.40 m (d) 0.53 m
Last Answer : Ans: (c) Correct Answer is: 0.45 m
Description : 02. The ratio of the inertia force to the gravity force is called Froude number. A) Agree B) Disagree
Description : Which of the following must be followed by the flow of a fluid (real or ideal)? (I) Newton's law of viscosity. (II) Newton's second law of motion. (III) The continuity equation. (IV) Velocity of boundary layer must be zero relative to ... . (A) I, II, III (B) II, III, V (C) I, II, V (D) II, IV, V
Last Answer : (B) II, III, V
Description : An ideal nozzle design aims at (A) Minimising wall friction (B) Suppressing boundary layer separation (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : What is the ratio of displacement thickness to nominal thickness for a linear distribution of velocity in the boundary layer on a flat plate? (A) 0.5 (B) 1 (C) 1.5 (D) 2
Last Answer : (A) 0.5
Description : The boundary layer thickness at a given section along a flat plate __________ with increasing Reynold's number. (A) Increases (B) Decreases (C) Remain same (D) May increase or decrease
Last Answer : (B) Decreases
Description : What is the spherical boundary of zero thickness in which photons that move around black holes called? -Space
Last Answer : A photon sphere or photon circle is an area or region of space where gravity is so strong that photons are forced to travel in orbits. (It is sometimes called the last photon orbit.) The radius of ... sphere, which is also the lower bound for any stable orbit, is, for a Schwarzschild black hole:
Description : At what value of Prandtl number, the hydrodynamic and thermal boundary layers of a fluid flowing over a heated plate will be identical? (A) 1 (B) < 1 (C) > 1 (D) None of these
Last Answer : (A) 1
Description : Boundary lubricated bearing is (A) Thick film bearing (B) Thin film bearing (C) Hydrodynamic bearing (D) Hydrostatic bearing
Last Answer : (B) Thin film bearing
Description : The hydrodynamic and thermal boundary layers will merge, when (A) Prandtl number is one (B) Schmidt number tends to infinity (C) Nusselt number tends to infinity (D) Archimedes number is greater than 10000
Last Answer : (A) Prandtl number is one
Description : Starting friction is low in case of the __________ lubrication. (A) Boundary (B) Hydrodynamic (C) Hydrostatic (D) Mixed/semi-fluid
Last Answer : (C) Hydrostatic
Description : An ideal flow of any fluid must satisfy (A) Pascal law (B) Newton's law of viscosity (C) Boundary layer theory (D) Continuity equation
Last Answer : Answer: Option D
Description : In hydrodynamic lubrication, film thickness remains unaffected by change in speeds. a) True b) Increase with increase in speed c) Decrease with increase in speed d) Disappear as the speed tends to infinty
Last Answer : b) Increase with increase in speed
Description : 19. The water hammer in pipes occurs due to sudden change in the velocity of flowing liquid A) Agree B) Disagree
Description : 05. When the end contractions of the weir are suppressed, then number of end contractions (n) are taken as zero. A) Agree B) Disagree
Description : Five volts are applied across the plates of a parallel plate capacitor. The distance of separation of the plates is .02 meters. What is the magnitude of the electric field inside the capacitor?
Last Answer : ANSWER: 250 VOLTS PER METER or 250 NEWTONS PER COULOMB
Description : When the seepage pressure becomes equal to the pressure due to submerged weight of a soil, the effective pressure is reduced to zero and the soil particles have a tendency to move up in the direction of flow. ... known (A) Quick condition (B) Boiling condition (C) Quick sand (D) All the above
Description : With regard to the cornea: a. photokeratitis occurs with wavelength of 270nm b. microvilli are found in the outer layer of the epithelium c. the turnover of the corneal epithelium typically takes 30 days d. the corneal epithelium is about 10 layers in thickness
Last Answer : photokeratitis occurs with wavelength of 270nm
Description : Thickness of a pavement may be reduced considerably by (A) Compaction of soil (B) Stabilisation of soil (C) Drainage of soil (D) Combination of all the above
Description : Bernoulli's equation describes the (A) Mechanical energy balance in potential flow (B) Kinetic energy balance in laminar flow (C) Mechanical energy balance in turbulent flow (D) Mechanical energy balance in boundary layer
Last Answer : (A) Mechanical energy balance in potential flow
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 : The length of the tube necessary for the boundary layer to reach thecentre of the tube and for fully developed flow to be established is called the __________ length. (A) Equivalent (B) Transition (C) Prandtl mixing (D) None of these
Last Answer : (B) Transition
Description : Boundary layer exists in flow (A) Of real fluids (B) Over flat surfaces only (C) In pipes only (D) Of ideal fluids only
Last Answer : (A) Of real fluids
Description : The effect of solid boundary on the fluid flow is confined to the boundary layer, except for fluids (A) Having high viscosities (B) Moving at low velocities (C) Both (A) & (B) (D) Neither (A) nor (B)
Description : __________ flow means the flow of incompressible fluid with no shear. (A) Potential (B) Streamline (C) Creep (D) Boundary layer
Last Answer : (A) Potential
Description : Existence of boundary layer in fluid flow is because of the (A) Surface tension (B) Fluid density (C) Fluid viscosity (D) Gravity forces
Last Answer : (C) Fluid viscosity
Description : The boundary layer is that part of a moving fluid, in which the fluid velocity is (A) Affected by the fluid flow pressure (B) Constant (C) Affected by the presence of a solid boundary (D) All (A), (B) and (C)
Last Answer : (C) Affected by the presence of a solid boundary
Description : The thickness of condensate layer in filmwise condensation depends on the (A) Condensation rate (B) Surface configuration (C) Liquid flow rate from the surface (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : When an isolated thermodynamic system executes a process, (A) Work is done (B) Heat transfer takes place (C) Mass flow occurs across the boundary of the system (D) No chemical reaction takes place within the system
Last Answer : D) No chemical reaction takes place within the system