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Dagong 12 hydraulic 1 spring runs online.

Total score of test paper: 100 Examination time:-Test paper score: 100

I. True or false (*** 10, ***40 points. ) score: 40

1. When the Reynolds number is relatively small, it shows that the mass force acting on the liquid flow plays a leading role.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

2. According to Darcy-Weisbach formula, when the pipe diameter, pipe length and average velocity of cross section are constant, the head loss along the way mainly depends on the head loss coefficient along the way.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

3. Any derived physical quantity dimension can be expressed as the exponential product of the basic physical quantity dimension.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

4. Xie Cai's formula is only applicable to laminar flow in principle, but it is also applicable to turbulent flow in hydraulic smooth pipes in practice.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

5. Although the hydrostatic pressure acting on the plane is perpendicular to the affected surface everywhere, the resultant force is not necessarily perpendicular to the affected surface.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

6. Wet perimeter refers to the perimeter of a solid wetted by liquid on the cross section of water.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

7. The shape of the constant basic flow does not change with time.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

8. Local head loss generally occurs when the cross-sectional shape, size and direction of water flow change and there are obstacles.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

9. The problem of water flow acting on solid boundary can only be solved by energy equation.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

10. The velocity and hydrodynamic pressure on the cross section of total flow must be evenly distributed.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

Second, multiple-choice questions (***5 questions, ***30 points. ) score: 30

1. All objects immersed in liquid are called submersibles, and the surface of the submersible is ().

A. Open plane

B. Open surface

C. Closed plane

D. closed surface

Answer: d

Full score: 6. Score: 6

2. When the absolute pressure at a point in the liquid is greater than the local atmospheric pressure, the relative pressure at that point is ().

A. positive value

B. negative values

C.0

D. uncertainty

A: A.

Full score: 6. Score: 6

3. According to the basic equation of hydrostatics, the pressure p changes with the water depth h in a () law.

A. parabola

B. straight line

C. hyperbola

D. Logarithmic relation curve

Answer: b

Full score: 6. Score: 6

4. In the pipeline flow, the hydraulic radius of a circular section with a diameter of d is ().

A.2d

B.d

C.d/3

D.d/4

Answer: d

Full score: 6. Score: 6

5. When a circular tube is in laminar flow, the average velocity on the water-passing section is () of the maximum velocity on the tube axis.

A.3 times

B. 1/3

C. Twice

D. 1/2

Answer: d

Full score: 6. Score: 6

Third, multiple-choice questions (***5 questions, ***30 points. ) score: 30

1. In turbulent motion, the corresponding turbulent shear stress is mainly composed of ().

A. Gravity shear stress

B. Viscous shear stress

C. Additional shear stress

D. mass inertial shear stress

Answer: BC

Full score: 6. Score: 6

2. The liquid flow can be divided into () according to whether the streamline is parallel.

A. uniform flow

B. non-uniform flow

C. turbulence

D. Slow flow

Answer: AB

Full score: 6. Score: 6

3. The three densities of liquid are ().

A. mass density

B. Weight density

C. relative density

D. bulk density

Answer: ABC

Full score: 6. Score: 6

4. The surface tension only occurs at the periphery of the liquid surface, and its action direction is ().

A. perpendicular to the perimeter line

B. Not perpendicular to the perimeter line

C. Tangent to the liquid surface

D. perpendicular to the liquid level

Answer: AC

Full score: 6. Score: 6

5. The main influence of water pulsation on the project is ().

A. Increase the action load

B. it is easy to cause vibration of hydraulic structures.

C. increase the energy loss of water flow

D. Causing riverbed erosion

Answer: ABCD

Full score: 6. Score: 6

Dagong 12 Spring 《 Hydraulics 》 Online Operation 2

Total score of test paper: 100 Examination time:-Test paper score: 100

I. True or false (*** 10, ***40 points. ) score: 40

1. In the qualitative analysis of the constant uneven gradient stream surface curve of the prismatic channel, there are no areas A and B on the critical bottom slope, only area C. ..

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

2. In the qualitative analysis of the constant uneven gradient water surface curve of prismatic channel, for the channel with positive bottom slope, when the channel is long and uneven flow cannot affect it, the water surface curve is tangent to the N-N line and the water flow tends to be uniform.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

3. In the first stage of water hammer phenomenon, when t=L/c, the water in the whole pipeline stops flowing and is under pressure.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

4. Hydraulic drop refers to the local hydraulic phenomenon that the water surface drops sharply when the water flows from slow to fast through the critical depth.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

5. When the water velocity is equal to the relative wave velocity, the upstream wave front peak of the interference wave stops at the interference source, and its influence range spreads from the interference source to the upstream. This water flow is called slow flow.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

6. From the construction point of view, the bottom slope I should be as consistent as possible with the terrain slope, so as to make the excavation and filling equal and reduce the project cost.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

7. In a prismatic open channel with constant cross-sectional shape, size and roughness, when the flow rate is constant, the steeper the bottom slope, the greater the normal water depth.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

8. In the simple long-pipe hydraulic calculation, only the head loss along the way is calculated.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

9. When judging the flow pattern of open channel water by water depth method, when the water depth is equal to the critical water depth, the flow rate is critical.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

10. In the water conservancy project, the materials used for the canal bottom and the side wall must be the same, so as to ensure the same roughness of each part of the section.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

Second, multiple-choice questions (***5 questions, ***30 points. ) score: 30

1. The characteristic of the series pipeline is the sum of the head losses of each section () the total acting head of the pipeline.

A. greater than

B. equal to

C. Less than

D. there is no information about

Answer: b

Full score: 6. Score: 6

2. In the qualitative analysis of constant non-uniform gradient stream surface curve of prismatic channel, if it is gentle slope, then ().

The A. N-N line is located above the k line.

The B. N-N line is below the k line.

C.N-N line coincides with k line.

D. there is no N-N line

A: A.

Full score: 6. Score: 6

3. In engineering, () is used to determine the pipe diameter.

A. Optimum length

B. Economic flow rate

C. Pipe height

D. flooding

Answer: b

Full score: 6. Score: 6

4. In the open channel uniform flow, the lowering value of the trough bottom elevation is equal to ().

A. piezometric tube head

B. Speed head

C. Local head loss

D. suffered heavy losses along the way

Answer: d

Full score: 6. Score: 6

5. Trapezoidal section irrigation channel with cross-sectional area of 75m2, wet perimeter 15m and hydraulic radius ().

A. 1.5 m

B.250 million

C.5m

D.20 meters

Answer: c

Full score: 6. Score: 6

Third, multiple-choice questions (***5 questions, ***30 points. ) score: 30

1. In the basic formula of a simple long pipe, the specific resistance a of the pipe is related to ().

A. pipe diameter

B. Velocity in the pipeline

C. coefficient of head loss along the way

D. water head

Answer: AC

Full score: 6. Score: 6

2. Froude number is a dimensionless number established by ().

A. Water velocity

B. cross-sectional area

C. speed head

D. relative wave velocity

Answer: AD

Full score: 6. Score: 6

3. In the study of hydraulic optimum section of trapezoidal channel, the following description about narrow and deep section is correct ().

A. Engineering Department

B. Large floor space

C. Vulnerable to geological conditions

D. dig deep during construction.

Answer: ACD

Full score: 6. Score: 6

4. The compound cross-section runner includes the main runner and the auxiliary runner. Under normal circumstances ().

A. in the middle is the main canal

B.there are auxiliary canals on both sides.

C. the hydraulic radius of the main canal is very large.

D. the auxiliary canal has a large hydraulic radius.

Answer: ABC

Full score: 6. Score: 6

5. The outflow of pressure pipeline can be divided into () according to the different outflow locations.

A. Atmospheric outflow

B. Free outflow

C. Water surface outflow

D. Submerged outflow

Answer: BD

Full score: 6. Score: 6

Dagong 12 Spring 《 Hydraulics 》 Online Homework 3

Total score of test paper: 100 Examination time:-Test paper score: 100

I. True or false (*** 10, ***40 points. ) score: 40

1. The outflow process of weir flow and sluice flow is the process of converting potential energy into kinetic energy.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

2. Generally, the entrance front of a broad-crested weir is relatively wide, and there are always piers and side piers, so there is no lateral contraction.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

3. Darcy formula Q=kAJ is summarized from the seepage of non-uniform flow.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

4. When the submerged hydraulic jump occurs downstream of the building, the energy dissipation wall is generally used to make the hydraulic jump a long-distance drive type.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

5. In the thin-walled weir flow, the rectangular thin-walled weir flow with lateral contraction submerged overflow is the most stable.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

6. When calculating the water depth of the downstream channel of the discharge structure, if there are buildings in the downstream channel, it should be calculated according to the uneven water surface curve.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

7. The underflow connection can only be dissipated by remote hydraulic jump.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

8. In a flow network, the flow between two streamlines is constant along the flow direction.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

9. Wide-crested weir flow can only be generated when the bottom sill causes the water flow to shrink.

A. mistakes

B. correct

A: A.

Full score: 4. Score: 4

10. The saturation line equation of earth dam can be in the form of pressureless gradual infiltration saturation line of flat-bottomed slope.

A. mistakes

B. correct

Answer: b

Full score: 4. Score: 4

Second, multiple-choice questions (***5 questions, ***30 points. ) score: 30

1. When the downstream water depth is less than that of the contraction section * * * yoke, () is generated.

A. Critical types

B. swing type

C. remote drive type

D. underwater

Answer: c

Full score: 6. Score: 6

2. When the sluice floor is a wide weir, when E/H >: 0.65, the water flow is ().

A. outflow from the drain hole

B. Overflow

C. Submerged outflow

D. Free outflow

Answer: b

Full score: 6. Score: 6

3. The submergence coefficient of broad-crested weir, when the relative submergence degree increases, its value is ().

A. Improve

B. Reduce

C. unchanged

D. uncertainty

Answer: b

Full score: 6. Score: 6

4. The well whose bottom hole falls on the first impermeable layer is called ().

A. completion under pressure

B. Incomplete well with pressure

C. pressureless completion

D. Non-pressure incomplete well

Answer: c

Full score: 6. Score: 6

5. The discharge coefficient of the curve practical weir changes with the water head, and its range is roughly ().

A.0.42-0.50

B.0.52-0.60

C.0.75-0.85

D.0.45-0.55

A: A.

Full score: 6. Score: 6

Third, multiple-choice questions (***5 questions, ***30 points. ) score: 30

1. According to the relative relationship between weir head and weir thickness, weir flow can be divided into several types ().

A. thin-walled weir flow

B. Actual weir flow

C. Sluice weir flow

D. Wide-crested weir flow

Answer: ABD

Full score: 6. Score: 6

2. In the outflow of the gate hole, the types of the gate are mainly ().

A. flat gate

B. Trapezoidal door

C. triangular door

D. radial gate

Answer: AD

Full score: 6. Score: 6

3. The determination method of permeability coefficient k mainly includes ().

A. Ecological remote sensing simulation method

B. Laboratory determination methods

C. On-site determination method

D. Empirical methods

Answer: BCD

Full score: 6. Score: 6

4. In the characteristics of jet energy dissipation, the following description is correct ().

A. Simple structure

B. Investment savings

C. Good energy dissipation effect

D. The energy dissipation effect is not good

Answer: ABC

Full score: 6. Score: 6

5. The main types of buckets are ().

A. continuous type

B. differential type

C. intermittent

D. impedance type

Answer: AB

Full score: 6. Score: 6