Download 山东大学 流体力学 课程试卷 2006-2007 学年 一 学期 题号 一 二 三 四

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地空
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土建与水利
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山东大学
流体力学
课程试卷
2006-2007
学年
一
学期
1
(5) A manometer is:
题号 一 二 三 四 五 六 七 八 九 十
总分
得分
1. Multiple Choice (34 points)
(1) The pressure at any point in a static fluid depends only on the;
A. Depth, surface pressure, and specific weight.
B. Depth and container shape.
C. Pressure and depth.
(2) When is an inclined-tube manometer used?
A. It can be used at any time.
B. When the fluid to be measured has a very low density
C. When the measured pressure changes are small
(3) When a surface is submerged in a fluid, the resultant pressure
force on the body acts in what manner? Assume no sheer forces are
present.
A. Perpendicular to the surface of the body.
B. In the same direction as the force of gravity.
C. There are no forces acting on the submerged body.
(4) The hydraulic grade line and what else are graphical forms of
the Bernoulli equation?
A. energy line
B. pressure line
C. viscous line
A. Temperature measuring device
B. Velocity measuring device
C. Pressure measuring device
(6) What does it mean when a flow is said to be inviscid?
A. The flow is moving at negligible velocity.
B. No acceleration is occurring.
C. The shearing stresses are negligible.
(7) In the derivation of the Bernoulli equation what is assumed to
be negligible?
A. pressure effects
B. streamlines
C. viscous effects
(8) The value of the Manning coefficient, n, depends on what?
A. The nature of the channel surface
B. The mass flow rate of the flow
C. The type of fluid
(9) Consider an open rectangular channel 3 m wide laid on a 1°
slop. If the water depth is 2m, the hydraulic radius is:
A. 0.43m
B. 0.60m
C. 0.86m
D. 1.00m
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山东大学
流体力学
课程试卷
学年
学期
(10) The 3-cm-diameter water jet produces a force of 23 N on this
2
1
plate when it strikes the plate. What is the average velocity of the
water in the jet ?
A. 2.85 m/s
B. 5.7m/s
C. 1m/s
D. 23m/s
(11) Consider an open rectangular channel 3m wide, the slope of (13) If a flow is unsteady, its ____ may change with time at a given
this channel is 0.0175. If this channel is built of rubble cement location.
(Manning’s n=0.020), what is the uniform flow rate when the water
A. Velocity
depth is 2m?
B. Temperature
A.18 m3/s
C. Density
3
B.35 m /s
D. All of the above
3
C.40 m /s
D.53 m3/s
(14) There is a variable diameter pipe with d1=320mm and
(12) When a uniform flat plate is placed horizontally at a depth of h
as shown in Figure 1, the magnitude of the force exerted by the d2=160mm, if velocity at point 1 is 1.5m/s, then velocity at point
fluid on the plate is 20 kN. When this plate is tilted about its center 2 is :
of gravity through 30º as shown in Figure 2, the magnitude of the
A.3m/s；
force (kN) exerted by the fluid on the plate is most nearly
B.4m/s；
A. 20 sin 30
C.6m/s；
B. 20 cos 30
D.9m/s.
C. 20 tan 30
D. 20
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山东大学
课程试卷
2 True or False (16 points)
(1) The wetted perimeter includes the free surface for open-channel
flows.
A. True
B. False
(2) If the flow is steady, there can be changes in velocity at different
locations in the flow field.
A. True
B. False
(3) Piezometric head line of the flow can go up or down along the
flow direction.
A. True
B. False
(4) The head loss of the flow in the straight pipe consists of
Frictional Losses and Minor Head Loss.
A. True
B. False
(5) Flow can cross a streamline.
A. True
B. False
（6）Head loss in laminar flow is independent of pipe roughness.
A. True
B. False
学年
学期
3
1
（7）In pipe flow the maximum shear occurs at the surface of the
pipe.
A. True
B. False
（8）Piezometric head increases with depth in a reservoir.
A. True
B. False
3. The dam in Fig. is a quarter circle 50 m wide into the paper.
Determine the horizontal and vertical components of the
hydrostatic force against the dam and the point CP where the
（12 points）
resultant strikes the dam.
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山东大学
课程试卷
学年
4. An overflow dam is shown in figure: the upstream water surface
rises because of the block of the dam; the water depth in section 1-1
is 1.5m; the depth in downstream section 2-2 is 0.6m; head loss is
negligible. What is the horizontal force F on 1-m-width dam
exerted by the stream?
(13 points)
学期
4
3
1
Fig. Flow through a siphon
6. The normal depth of flow in a trapezoidal concrete lined channel
is 2m .The channel base width is 5m and has side slopes of 1
vertical to 2 horizontal. Manning’s n is 0.015 and the bed slope, S0,
is 0.001. Determine the discharge (Q), mean velocity (V) and the
5. Water discharges from a reservoir, as shown in figure .The pipe Reynolds Number (Re).
diameter is 100mm and has length 15m and discharges direct to the
atmosphere at point C 4m ,below the surface of the reservoir (i.e. za
– zc = 4.0m). The highest point on the pipe is a B which is 1.5m
above the surface of the reservoir (i.e. zb – za = 1.5m) and 5 m along
the pipe measured from the reservoir. Assume the entrance and exit
to the pipe to be sharp and the value of friction factor λ to be 0.32.
(for entry loss kL = 0.5)
Calculate a) the mean velocity of water leaving the pipe at point C,
b) the pressure in the pipe at point B.
(13 points)
(12points)
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