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155 Cards in this Set
- Front
- Back
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Energy |
is the ability to work. |
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Work |
is the transfer of energy. |
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The energy used in drying one person's hair using a hairdryer might be expected to be... |
about 3 kW h. |
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The energy used in using a kitchen toaster to toast two pieces of bread might be expected to be... |
60 kJ. |
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Embodied energy can be defined as... |
the primary energy consumed over the life cycle of the material concerned. |
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A wingtip vortex is |
has similarity to a free vortex. |
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A toroidal vortex forms |
because vortices "tend to abhor" a free end. |
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Disc drives principally consume energy... |
due to windage between the rotating discs and surrounding fluid. |
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Albedo refers to |
the fraction of Sun's radiation reflected form a surface. |
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A wind tends to be described |
depending on velocity. |
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In a bypass engine |
only a fraction of the air goes through the combustor. |
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The Navier-Stokes equations concern The equivalency of heat and work, The balancing of inertial terms by pressure gradient, viscous and heat terms, The balancing of inertial terms by pressure gradient, inviscid and body forces terms, The balancing of inertial terms by pressure gradient, viscous and body forces terms, The definition of temperature. |
the balancing of inertial terms by pressure gradient, viscous and body forces terms. |
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Fourier's equation for heat conduction is given by... |
q = -k dT/dx. |
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Newton's law of cooling is given by... |
q = h(Ts-Tf) |
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Heat transfer due to radiation between a small object and its surroundings, can be modeled by... |
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The second law of thermodynamics can be stated as |
it is impossible to construct a device that operated on a cycle whose sole effect is the transfer of heat from a cooler to a hotter body. |
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How much energy is there typically in a liter of petrol approximately... 1 MJ, 10 J, 100 MJ, 4 J, 40 MJ. |
40 MJ. |
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One calorie is defined as equivalent to... 4184 J, 1 kJ, 4 MJ, 3.6 kW h, 10 tubs of margarine. |
4184 J. |
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How many Pascals are there in 1 bar? 10, 100, 1 000, 10 000, 100 000. |
100 000. <- (10^5) |
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Newton's second law can be states as |
F=m*a |
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The units of shear stress are? m^3/g, N/g, kg/m^3, N m/kg, N/m^2. |
N/m^2. |
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The units of viscosity are... N s/m^2, Pa kg, Pa s/m, kg/m^2, kg s/m. |
N s/m^2. |
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The density of air at atmospheric pressure and 20 (degrees) C is approximately... 3, 1*10^6, 0.01, 1.2, 1000. |
1.2 kg/m^3. |
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Which of the following equations relating the shear stress experienced by fluids to the velocity gradient is correct? |
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Kinematic viscosity is defined as... |
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Which os the following fluids has the highest viscosity at 20 (degrees) C? Petrol, hydrogen, air, water, SEA 10W oil. |
SAE 10W oil. |
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The submarine dives to 100 m below the sea surface. If the approximate atmospheric pressure at sea level is 1 bar what is the approximate gauge pressure that will be experiences by the submarine? 9 900 000, 10 000 000, 100 001, 100 000, |
UPDATE: 10 100 000 Pa. |
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What pressure is 1 m head of water approximately equivalent to? 1 000 Pa, 100 Pa, 10 Pa, 1 Tor, 10 000 Pa. |
10 000 Pa. |
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The perfect gas law is given by... |
(only one including density of the options). |
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The Reynolds number is given by... |
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The flow in a pipe is likely to be laminar if the Reynolds number is < 100 000, < 2 000, > 4 000, > 100 000, highly turbulent. |
< 2000. |
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Which of the following statements concerning the Reynolds number is true? The Reynolds number is indicative of the relative importance of inertia and viscous forces in theflow, The Reynolds number of a flow is always constant, The Reynolds number is a measure of volume, The maximum possible Reynolds number is 4000, Flow is laminar if the Reynolds number is less than 4000. |
The Reynolds number is indicative of the relative importance of inertia and viscous forces in the flow. |
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The pressure in a body of fluid... Is constant with depth, varies with depth, is always 1 bar, can be measured in kelvin, varies exponentially with depth. |
varies with depth. |
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Which of the following statements is true? Equal to the product of density, tangential, equal to the sum, equal to the product of viscosity, perpendicular. |
A streamline is tangential to the direction of the velocity vector at any point. |
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The substantive derivative, Dv/Dt is given by... |
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Which of the following definitions for the stress tensor is correct? |
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The characteristic gas constant for air is... 28.7 J/kg K, 2.87 kJ/kg, 287 W/m K, 287 J/kg K, |
287 J/kg K. |
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Stresses that change the shape of an element are referred to as... von-Mises stresses, deviatoric stresses, diametral stresses, von-Karman vortices, streamlines. |
deviatoric stresses. |
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Bernoulli's equation is invalid for which of the following conditions... Frictionless flow, compressible flow, steady flow, along a streamline with no shaft work, for an adiabatic flow. |
compressible flow. |
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What are the three fundamental equations for modelling fluid flow? Momentum, continuity and Planck’s law. |
continuity, momentum and energy. |
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Which of the following is a true statement for the one dimensional continuity equation? |
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What are the units of volumetric flow rate? kg s/m^3, m^3, m^2/s, kg/s, m^3/s. |
m^3/s. |
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Which of the following statements as the units Watts per meter per kelvin? W/mK, W/m K, W m K^(-1), WmK, W/mk. |
W/m K. |
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Water flowing through a 0.25 m diameter pipe with a mass flow rate of 100 kg/s had an average speed of? 9, 0.1, 100, 0.987, 2.04. |
2.04 m/s. |
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The continuity equation for two dimensional flow is given by... |
(the positive one with u,v,x,y). |
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Bernoulli's equation for flow between arbitrary points along a streamline states... |
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The force momentum equation for flow along a streamline can be expressed as... |
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The tree modes of heat transfer are... |
conduction, convection and radiation. |
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Heat transfer is... Energy in transit, power in transit, the transfer of particles, radiation of energy, the transfer of energy. |
UPDATE: Energy in transit. |
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Fourier's law of heat conduction can be stated in the form... |
q = - kdT/dx. |
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The units of heat flux are... W, J, J/m^2, N m, W/m^2. |
W/m^2. |
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The units of thermal conductivity are... W/m^2, W, J/K, W/m K, W/mK. |
W/m K. |
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Newton's law of cooling can be stated in the form... |
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The units of the hear transfer coefficient are... Btu, kW h, W/m K, W/m^2K, W/m^2. |
W/m^2K. |
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The value of the heat transfer coefficient depends principally on... conditions in the solid surface. the thermal conductivity of the surface. the temperature gradient within the solid. conditions in the boundary layer. the emissivity of the surface. |
conditions in the boundary layer. |
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Heat transfer due to radiation between a small object and its surroundings, can be modeled by... |
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For a cylindrical application, the critical insulation radius is... The radius at which the heat flux is a maximum, The radius at which the heat flux begins to reduce, The largest radius at which adding more insulation will create an increase in the heat loss, The radius at which there is an onset of heat loss due to thermal radiation, The radius at which adding more insulation will reduce the heat loss. |
the largest radius at which adding more insulation will create an increase in the heat loss. |
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One of the simplest methods of modelling transient conduction is... Newton's law, Lapace's equation, Navier-stokes, lumped capacitance, Planck's law. |
using the lumped capacitance method. |
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The Biot number is defined by... kL/h, kL/Pr, hL/k, Pr/u, uCp/k. |
hL/k. |
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The Nusselt number is defined by... Nu=hL/k, Nu=L/k, Nu=h/k, Nu=hL^2/k, Nu=kL/h. |
Nu = hL/k. |
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If a hot object's color is perceived to be dull red, its approximate temperature is... 50, 700, 100, 1500, 2000. |
700 (degrees) C. |
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Which of the following is a true statement for a blackbody. A blackbody emits, a blackbody absorbs, radiation emitted, spectral emissive (x2). |
A blackbody absorbs all incident radiation regardless of wavelength and direction. |
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Stefan-Boltzmann's Law can be stated by... |
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The surface property limiting the quantity of radiation is called... Reflectivity, reflectance, emissivity, transmissivity, resistivity. |
emissivity. |
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Emissivity is defined on a scale from... 0 to 10, 1 to 10, 0.1 to 1, 0 to 1, 1 to 100. |
0 to 1. |
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What is the optical efficiency of an automobile internal combustion engine? 14, 70, 35, 2, 90. |
35 %. |
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What is the peak efficiency for a home furnace (chemical to thermal)? 2, 14, 90, 70, 25. |
70 %. |
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A system in thermodynamics can be describes by which of the following statements. Refers-matter, contain-matter, refers-energy, refers-entropy, contain-entropy. |
A thermodynamic system refers to a definite quantity of matter being analysed within prescribed and identifiable boundaries. |
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Which of the following is not extensive property? |
Temperature. |
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Which of the following in an inadequate description of temperature? Temperature is defined... (x2), The temperature of..., Temperature is the..., Temperature defines... |
Temperature defines the kinetic energy associated with the molecules in fixed quantity of matter. |
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Which of the following is not a type of energy? |
Pressure. |
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Which of the following is not a unit of energy? |
kW. |
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Which of the following is not a process normally associated with thermodynamics? Adiabatic, isothermal, sedimentation, isentropic, isenthalpic. |
Sedimentation. |
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The critical point for water occurs at the pressure of... 22.09 MPa, 1.0325 bar, 100 000 Pa, 10 MPa, 293 K. |
22.09 MPa. |
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The ideal gas equation can be written in the form... |
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An example of a valid analytic relationship for pressure and volume is the polytropic process modeled by which of the following? |
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Which of the following is not an expression of the 1st law of thermodynamics? |
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Which of the following processes is not associated with a Carnot cycle? An isothermal expansion, an adiabatic reverse expansion, an polytropic expansion, an isothermal compression, an adiabatic reversible compression. |
An polytropic expansion. |
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The efficiency of a Carnot cycle is given by... |
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Which of the following is not an appropriate means of defining the coefficient of performance for a refrigerator? |
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Which of the following components would not normally be associated with a gas turbine engine? Compressor, turbine, combustor, bearing, condenser. |
Condenser. |
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The turbine inlet temperature in a state of the art jet engine might be expected to be approximately?
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1600 (degrees) C. |
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Which of the following components would not normally be associated with a turbocharger? Radial turbine, combustor, centrifugal compressor, bearing, shaft. |
Combustor. |
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Static pressure for flow in a pipe can be measured by... A Pitot tube, a thermometer, connecting a pressure sensor-acute angle, connecting a pyrometer, connecting a pressure sensor-perpendicular. |
connecting a pressure sensor to a holde drilled perpendicular to the pipe wall surface.
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For subsonic incompressible steady flow through a diverging duct, which of the following is true? Both decrease, speed increase and pressure decreases, speed decreases and pressure increases, both increase, no change. |
The speed decreases and the pressure increases. |
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Which of the following cannot be used to measure mass flow rate?
A bucket, a Venturi meter, an orifice plate, a blanking plate, a Pitot tube. |
A blanking plate. |
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The drag coefficient is defined by... |
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Drag is defined as... The stress..., the turbulence..., the force-direction, the force..., the shear stress... |
the force component exerted on a body by a moving fluid in the direction of the free stream remote from the body. |
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Drag principally comprises two components... Skin and color drag, noise and turbulent drag, skin and form drag, form and function drag, Reynolds and Mach drag. |
skin and form drag. |
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For a flat plate at zero incidence, the drag force is entirely... due to magnetism, due to gravity, due to chemical reaction, due to friction, due to radiation. |
due to friction.
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For a flat plate oriented at 90 (degrees) to the flow, the drag is entirely due to... Separation, radiation, magnetism, gravity, chemical reaction. |
entirely due to separation. |
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For which of the following geometries is the drag coefficient less than 1? Cube, disk, cup, 60 (degrees) cone, parachute. |
60 (degree) cone. |
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The frontal area is suitable for evaluating the drag coefficient for all expect which one of the following bodies? Bluff bodies, cylinders, spheres, automobiles, wings. |
Wings. |
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The planform area is suitable for evaluating the drag coefficient for which of the following bodies? Aerofoils, missilies, cylinders, spheres, ships. |
Aerofoils. |
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The wetted area is suitable for evaluating the drag coefficient for which one of the following bodies? Spheres, cylinders, ships, wings, automobiles. |
Ships. |
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The drag coefficient for a flat plate at an angle to a flow... Is equal to the lifht coefficient, is always 0.4, is always less than 0.1, is 0, increases with inclination angle. |
increases with inclination angle. |
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For flow around a cylinder what is the dominant mechanism for drag? Magnetism, pressure drag, gravity, radiation, chemical reaction. |
Pressure drag. |
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Why is the drag coefficient for a sphere for a turbulent flow lower than for laminar flow? Because the flow is slower, because of magnetism, because the flow separates, because of gravity, because the Reynolds number is less than 2. |
Because the flow separates.
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The drag coefficient for sharp edged or bluff bodies, which tend to cause flow separation are insensitive to the effects of... Trailing edge geometry, angle of incidence, upstream conditions, Reynolds number, geometrical configurations. |
UPDATE: Reynolds number. |
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The drag coefficient for a cylinder for turbulent flow conditions will be approximately... 0.003, 300, 12, 1.2, 0.3. |
0.3
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The drag coefficient for a cylinder for laminar flow conditions will be approximately... 1.2, 12, 0.003, 0.3, 30. |
1.2 |
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The drag coefficient for car modeled by potential flow will be...
At least..., equal..., larger..., 90, 0.36. |
At least... |
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The drag coefficient for a modern production sports car will typically be approximately... 40, 0.36, 3600, 36, 3.6. |
0.36 |
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Does the power required to overcome drag... increase exponentially with speed, decrease with speed, remain constant, increase with speed, decrease exponentially with speed. |
increase exponentially with speed. |
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At 100 km/h approximately what proportion will aerodynamic drag account for in terms of the overall resistance to motion? 6.5, 0.65, 65, 100, 0. |
6,5 %. |
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Which of the following vehicles had the lowest drag coefficient? A typical tractor trailer rig, BMW 5 series, Mercedes 300E, Porsche 928, Porsche 944. |
Porsche 928. |
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Which of the following statements is untrue concerning the Moody chart? |
UPDATE: Do not know the answer. |
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Laminar flow is likely to occur in a pipe for Reynolds numbers of less than... 5 000, -2 000, 2 000, 6 000, 100 000. |
2000. |
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The velocity profile for fully developed laminar flow in a pipe is given by... |
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For fully developed laminar pipe flow... |
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Pressure loss in a pipe can be evaluated using... |
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The Reynolds stress. |
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u+ and y+ are called... Wall shear stresses, universal stresses, universal coordinates, local coordinates, absolute coordinates. |
Universal coordinates. |
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The 1/7th power law profile for the velocity profile in fully developed turbulent pipe flow is given by... |
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The average and maximum speed for turbulent fully developed pipe flow are given by... |
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Pressure losses are likely to occur for all except which one of the following pipe fittings? Exit from a pipe, sudden decrease in pipe diameter, bends, bell mouth intake, partially closed valve. |
Bell mouth intake. |
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The pressure for flow going around a bend is... Lower on the outside of the bend, higher on the outside of the bend, lowest on the center line, uniform, highest on the innermost radius. |
Higher on the outside of the bend. |
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The units for head are given by... N, N/m^2, m, m^2, Pa s. |
m. |
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Pressure loss due to pipe friction and miscellaneous pipe fittings can be modeled by which of the following equations? |
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For flow in a pipe, for the same value of Q, halving the diameter increases the frictionalpressure drop by a factor of... 1, 14, 32, 16, 64. |
32. |
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The effect of pipe fittings on pressure loss can be expressed as... |
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The pressure loss due to a sudden contraction is given by... |
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The viscosity of water is approximately... 0.1 N m, 0.001 kg/m s, 0.1 nNm, 0.001 kg/m^3, |
0.001 kg/m s. |
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The typical loss coefficient for a 90 (degree) elbow will be about... 90, 900, 0.9, 0.009, 100. |
0.9. |
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A typical value of friction factor for turbulent flow in a cast iron pipe will be of the order of... 2, 20, 200, 0.0002, 0.02. |
0.02. |
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Turbulent viscosity. |
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A thermocouple functions as a result of... The Seebeck effect, variation of resistance with temperature, variation in emissivity with temperature, chemical reaction, variation of resistance with pressure. |
The Seebeck effect. |
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A suitable correlation for modelling turbulent heat transfer in a pipe might be... |
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Which of the following equations can be used to determine the speed of flow measured by aPitot tube? |
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Which of the following are a statement of the Navier-Stokes equations for two-dimensionalflow? |
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The first law of thermodynamics can be stated as... |
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The units of heat are... W, J, W/m^2, W/m^3, K. |
J. |
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The energy equation for steady, two-dimensional flow of a compressible fluid with variableproperties can be stated as... |
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For subsonic flow, separation occurs in divergent nozzle with steep angles of divergence due to... Formation of shock waves, the adverse pressure gradient in the diffuser, constant pressure in the diffuser, Maxwell’s demon, the favourable pressure gradient in the diffuser. |
The adverse pressure gradient in the diffuser. |
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Flow in a compressor overcomes the adverse pressure gradient due to... Gravitation, magnetism, buoyancy, the momentum of the flow, temperature gradients. |
The momentum of the flow. |
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The Prandtl number is defined by... |
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The boundary layer thickness, defined as the distance at which the velocity is almost equal tothe free stream velocity and is usually denoted by (see fig.) In this context, what percentage isnormally used as the convention for being ‘almost equal’? 90%, 99%, 99.9%, 95%, 100%. |
99 %. |
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The Prandtl number signifies... Whether a flow is laminar or turbulent, temperature, viscosity, the relative thickness of the momentum to the thermal boundary layer, the heat capacity of a fluid. |
The relative thickness of the momentum to the thermal boundary layer. |
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The Prandtl for air at atmospheric pressure and temperature is typically taken as... 2.17, 7, 0.7, 287, 700. |
0.7. |
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The entry length region of a pipe is typically taken to be about... 5 diameters equivalent length, 50 diameters equivalent length, 500 diameters equivalent length, 1 m, 0.1 m. |
50 diameters equivalent length. |
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Which of the following equations correctly defines the relationship for shear stress variation in a pipe? |
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The shear stress at the centre of a pipe for fully developed flow is, theoretically... Zero, infinite, 12 N/m^2, 287 N/m^2, a maximum for the flow. |
Zero. |
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The Reynolds number for pipe flow is given by... |
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Water flowing at an average speed of 0.8 m/s through a 0.5 m diameter pipe has a Reynoldsnumber of... 3, 4 000, 78.4, 400 000, 90 000. |
400 000. |
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The viscosity of air at atmospheric pressure and temperature is approximately... |
1.85*10^(-5) Pa s. |
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Darcy’s equation for the pressure loss due to friction in a pipe is given by... |
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The skin friction coefficient is defined by... |
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The friction factor and skin friction coefficient are related by... f = Cf, f = 4Cf, f = 16Cf, f = 65Cf, f = 0.25Cf. |
f = 4Cf. |
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The Reynolds number for flow over a plate is given by... |
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For flow over a flat plate, the breakdown from laminar to turbulent flow occurs somewhere inthe range... |
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Which of the following statements concerning a boundary layer is untrue? The transition to turbulence results in a rapid growth of the boundary layer thickness, Boundary layer theory acknowledges the presence of fluid viscosity, A boundary layer for turbulent flow can be modelled by three zones: the laminar sublayer, thebuffer region and the turbulent core, viscosity has no effect in a boundary layer,The boundary layer thickness is normally denoted by the symbol (see notes). |
Viscosity has no effect in a boundary layer (untrue). |
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On which two parameters is the friction factor generally dependent? |
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What is the critical parameter that governs the transition from laminar to turbulent flow for a flat-plate boundary layer... The diameter, the viscosity, the density, the Reynolds number, the roughness. |
The Reynolds number. |
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For which of the following range of Reynolds numbers for pipe flow would the flow be classedas transitional? |
2 000 < Red <4 000 |
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Approximately how thick is the boundary layer at the end of a typical train? 0.005 m, 50 m, 1 m, 10 m, 0.001 m. |
1 m. |
