山东大学
- Which results in more efficient heat exchange, laminar or turbulent flow?
- How is an orifice meter constructed?
- Streamline coordinates consist of what two components in 2-D form?
- Typically, in fluid mechanics the required number of reference dimensions is ____. ____
- Turbulent pipe flow properties depend on the fluid ____ and the ____. ____, ____
- Similarity laws can be directly developed from the ____ governing the phenomenon of interest. ____
- The ____ is the control volume expression for the conservation of mass. ____
- The ratio of fluid velocity to the speed of sound is referred to as the ____. ____。
- The Bernoulli equation applies along a ____ for ____ fluids. ____, ____
- If the viscosity is set to zero, the Navier-Stokes equations reduce to ____ equations. ____
- Models for which one or more of the similarity requirements are not satisfied are called ____ models. ____
- Steady laminar flow between fixed plates is ____ to the pressure gradient and is ____ to the viscosity. ____, ____
- An airfoil is designed so that the fluid velocity over its upper surface is ____ than that along its lower surface. ____。
- The _____ line is a line that represents the total head available to the fluid. ____。
- The ____ equations are the basic differential equations describing the flow of Newtonian fluids. ____
- Kinetic energy change is often accompanied by a change in ____. ____。
- The second similarity requirement indicates that the model and the prototype must be operated at ____. ____
- A qualitative description of physical quantities can be given in terms of ____. ____
- The number of variables is desired to be kept to a minimum so that the amount of ____ can be kept to a minimum. ____
- Work is transferred by rotating shafts, normal stresses, and tangential stresses. True or False? （ ）
- The Bernoulli equation is not valid for flows that involve pumps or turbines. True or False? （ ）
- The flow of river water is significantly affected by surface tension. （ ）
- The pressure or force of gravity can cause a fluid flow element to rotate. True or False? （ ）
- Flow meters based on the Bernoulli equation, used to measure flowrates in open channels such as flumes and irrigation ditches, include devices like the sluice gate and the sharp-crested weir. True or False? （ ）
- Distorted models cannot be successfully used, only true models can be accurately used. （ ）
- The amount of mass in a system is constant. True or False?（ ）
- When velocity ratios and acceleration ratios are constant throughout the flow field, kinematic similarity exists between the model and the prototype. （ ）
- Examples of a source and a sink are a pump and a turbine. True or False? （ ）
- For some problems it is more convenient to express the various differential relationships in cylindrical coordinates rather than in Cartesian coordinates. True or False? （ ）
- Model design conditions are also called similarity requirements or modeling laws. （ ）
- The number of required pi terms is fixed in accordance with the pi theorem. （ ）
- For complicated problems it is often less feasible to use models to predict specific characteristics of the system than to develop general correlations. （ ）
- Variables can be classified into three general groups: geometry, material properties, and external effects. （ ）
- The velocity at a stagnation point will be greater than the velocity at surrounding areas. True or False? （ ）
- A potential flow vortex is rotational. True or False? （ ）
- The effect of pressure on viscosity is usually neglected. True or False? （ ）
- The Bernoulli equation can be derived from the energy equation. True or False? （ ）
- ____ represents a flow in which the streamlines form concentric circles. ( )
- How is flow around a half body obtained? ( )
- The Reynolds transport theorem provides the relationship between ( )
- The Weber number is a relationship between the inertial force and what other force? ( )
- What is the definition of specific gravity? （ ）。
- An adiabatic process means that there is no heat transfer and no ____. （ ）。
- The German professor Ludwig Prandtl introduced the concept of what? （ ）。
- Steady, fully developed pipe flow experiences no ____. ( )
- What term is used when the fluid pressure is reduced to the vapor pressure? （ ）。
- Streamwise acceleration is the product of the rate of change of speed with distance along the streamline, , and what else? （ ）。
- A 2-in. diameter shaft is supported by two sleeves, each of length = 2 in. The internal diameter of the sleeves is 2.1 in. The radial space between the shaft and the sleeves is filled with an oil of viscosity = 8 × 10-3 lb-s/ft2. If the shaft is rotated at a speed of 600 rpm, the viscous torque (ft-lb) on the shaft is most nearly （ ）。
- As a “rule of thumb,” a perfect gas may be considered incompressible for which range of Mach numbers? （ ）。
- The most difficult step in the method of repeating variables is ____. ( )
- When measuring the static pressure, one way to do so would be to do what? （ ）。
- Units of ____ are used to quantify the amount of head involved. ( )
- A change in fluid velocity that results in a change in the elevation of the hydraulic grade line is due to: （ ）。
- How do the dimples on a golf ball effect drag? ( )
- For the laminar flow of a Newtonian fluid, the shear stress is proportional to the ____. ( )
- The three most common devices used to measure the instantaneous flowrate in pipes are ____, ____, and ____. ( )
- An external effect is used to denote any variable that produces or tends to produce what? ( )
- The pi terms must always be what? ( )
- For time-dependent problems, which of the following is crucial for successfully finding a solution? ( )
- Raindrops with a radius less than 0.5 mm are what shape? （ ）。
- Another term for the speed of sound is what? （ ）。
- What is the relationship between the Reynolds transport theorem and the material derivative? ( )
- If a cylinder is rotated in a uniform flow, what happens to the stagnation point? ( )
- What is a general description of the flow rate in laminar flow? ( )
- For large Reynolds numbers, the inertial forces are ____ the viscous forces? ( )
- Which of the three meter types is the most accurate? ( )
- What is the value of the vorticity in irrotational flow fields? ( )
- A representation of a physical system that may be used to predict the behavior of the system in some desired respect is what? ( )
- The development of vapor pressure closely relates to ____. （ ）。
- A 2-in. diameter cylinder is floating vertically in seawater with 75% of its volume submerged. If the specific gravity of seawater is 1.03, the specific weight (lb/cu ft) of the cylinder is most nearly （ ）。
- If shaft work is involved then the local flow must be____. ( )
- Parallel plate flow where one plate moves with constant velocity is called ____ flow. ( )
答案:Turbulent flow results in more efficient heat exchange.
答案:By inserting a flat plate with a hole between two flanges of pipe.
答案:Along the streamline, s, and perpendicular to the streamline, n.
答案:Three
答案:pipe roughness
答案:dimensionless parameters
答案:The mass flow rate equation is the control volume expression for the conservation of mass.
答案:Mach number
答案:inviscid
A:错 B:对
A:对 B:错
A:对 B:错
A:对 B:错
A:错 B:对
A:对 B:错
A:对 B:错
A:错 B:对
A:对 B:错
A:错 B:对
A:错 B:对
A:对 B:错
A:错 B:对
A:对 B:错
A:对 B:错
A:对 B:错
A:对 B:错
A:错 B:对
A:A vortex
B:None
C:A source
D:A sink
A:By adding a vortex to a uniform flow
B:By adding a source to a uniform flow
C:By adding a source and a sink
D:By adding a sink to a uniform flow
A:The time rate of change of the fluid mass and the control volume.
B:The time rate of change of the shape of the fluid and the control volume.
C:The time rate of change of an extensive property of the system and the control volume.
D:None.
A:gravity
B:kinetic
C:surface tension
D:frictional
A:the weight per unit gravity
B:the ratio of the density of a water to the density of water
C:the ratio of the density of water to the density of a fluid
D:the ratio of the density of a fluid to the density of water
A:Pressure losses
B:friction
C:Change in velocity
D:none
A:fluid mechanics
B:fluid statics
C:aerodynamics
D:fluid boundary layer
A:Motion
B:Velocity
C:Acceleration
D:Friction
A:Cavitation
B:Bernoulli effect
C:Differential
D:None
A:the viscosity
B:the acceleration
C:the speed
D:the pressure
A:0.64
B:0.15
C:6.40
D:3.20
A:less than 0.3
B:greater than 0.5
C:less than 0.7
D:greater than 0.3
A:express each of the variables in terms of basic dimensions
B:None
C:listing all of the variables that are involved in the problem
D:determine the required number of pi terms
A:Check the pressure at the beginning of the flow and compare it to the end
B:None
C:Drop a manometer in the middle of the flow of a fluid
D:Drill a hole along the flat surface and attach a piezometer tube
A:mass
B:force
C:length
D:time
A:Change in pipe diameter
B:Change in pressure
C:Change in force exerted on the fluid
D:none
A:they increase drag
B:they do not effect drag
C:none
D:they reduce drag
A:frictionless
B:velocity gradient
C:amount of friction
D:no-slip condition
A:Venturi meter, orifice meter, nozzle meter.
B:none.
C:Voltmeter, Amp meter, orifice meter.
D:Potentiometer, orifice meter, nozzle meter.
A:change in the system
B:inaccurate results
C:none
D:constant results
A:constant
B:dimensionless
C:negative
D:equal in dimensions
A:Initial conditions
B:The velocities at all points
C:none
D:The derivative of the equation
A:ring shaped
B:ball coronary
C:spherical
D:teardrop
A:absolute velocity
B:relative speed
C:acoustic velocity
D:acoustic speed
A:The Reynolds transport theorem is the material derivative equivalent for unsteady flow.
B:There is no relationship.
C:None.
D:The Reynolds transport theorem is the integral equivalent of the material derivative.
A:It moves along the surface of the cylinder, and can even move off of the surface of the cylinder.
B:It moves along the surface of the cylinder.
C:It moves.
D:It never moves.
A:Large
B:Creep
C:Turbulent
D:Small
A:Larger than
B:Approximately the same as
C:Less than
D:fewer than
A:Orifice
B:None
C:Venturi
D:Nozzle
A:Zero
B:Infinity
C:It is proportional to the velocity of the flow
D:Constant
A:Model
B:Prototype
C:Facsimile
D:Experiments
A:the boiling point
%1. atmospheric pressure
%1. none
B:molecular activity
A:48.2
B:64.2
C:83.2
D:85.7
A:steady
B:unsteady
C:turbulent
D:laminar
A:Constant
B:Couette
C:Eulerian
D:Viscous
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