流体力学（fluid mechanics）

1、流体力学（fluid mechanics）1., the factors relating to Newtons law of internal friction are:A, pressure, velocity and viscosity; B, fluid viscosity, shear stress and angular deformation rate;C, shear stress, temperature, viscosity and velocity; D, pressure, viscosity and angular deformation.2., in the stu

2、dy of fluid movement, the fluid can be divided into two parts according to whether or not the viscosity of the fluid is considered:A, Newton fluid and non Newton fluid, B, compressible fluid and incompressible fluid;C, homogeneous fluid and heterogeneous fluid, D, ideal fluid and real fluid.3. the f

3、ollowing four statements about the quality and weight of fluids are correct and rigorous.A the mass and weight of a fluid do not vary with position;B the mass and weight of a fluid vary with position;C the mass of a fluid varies with position while its weight remains constant;D the mass of the fluid

4、 does not vary with position, but the weight varies with position.4. fluid is a substance.A continues to expand until it is full of containers; B is actually incompressible;C, can not withstand the shear stress; D, not in a shear effect remains stationary.5. shear stress of fluid.A does not occur wh

5、en the fluid is at rest;B, when the fluid is in a stationary state, due to cohesion, can be produced;C depends solely on the momentum exchange of molecules;D depends solely on cohesion.The dynamic viscosity of 6.A and stationary liquid is 0, and the kinematic viscosity of B and stationary liquid is

6、0;The shear stress of C and stationary liquid is 0; the compressive stress of D and stationary liquid is 0.7. ideal liquids are characterized byA, viscosity constant B, non sticky C, incompressible D, in line with.8. hydraulics, unit mass force refers to the role in the _ force per unit mass of liqu

7、id.A, area B, volume C, mass D, weightThe dimension of the mass force of 9. units isA, L*T-2, B, M*L2*T, C, M*L*T (-2), D, L (-1), *T10. per unit volume of the weight of the liquid is called liquid _, its unit.A, bulk density N/m2 B, bulk density N/M3 C, density kg/m3 D, density N/m311. different li

8、quid viscosity with the viscosity _, a liquid is decreased with the temperature _.A, the same reduction of B, the same elevated C, different D, different elevation12. liquid viscosity with increasing temperature _, gas viscosity increased with increasing temperature and _.A, decrease, rise, B, incre

9、ase, decrease, C, decrease, change, D, decrease, decrease13. dimension of coefficient of kinematic viscosity is:A, L/T2, B, L/T3, C, L2/T, D, L3/T14. the unit of dynamic viscosity is:A, N*s/m, B, N*s/m2, C, m2/s, D, m/s15. the following statement is correct:A, the liquid can not bear tension, and ca

10、n not afford the pressure. B, liquid can not bear the tension, but can withstand the pressure.C, liquid can bear tensile force, but it cant bear pressure.D, the liquid can bear tension, but also can withstand the pressure.The second chapter, fluid statics1. in a stationary liquid under the action of

11、 gravity, the isobaric surface is a horizontal surface, and the condition is that.A and the same liquid; B and interconnected;C and disconnected; D, same liquid, communicating with each other.2. the reading value of the pressure gauge isA, absolute pressure;B, the difference between absolute pressur

12、e and local atmospheric pressure;C, absolute pressure plus local atmospheric pressure;D, the difference between the local and absolute pressures.3. relative pressure is the difference between the absolute pressure at that point and the point.A, standard atmospheric pressure; B, local atmospheric pre

13、ssure; C; engineering atmospheric pressure; D; vacuum pressure.4. there are two different liquids in the container. The density is, and there isA, B,C, D,5. shown in a closed vessel of water, 1, 2 and 3 are on the same horizontal plane:A, B, C, D,6. use U mercury manometer to measure A point pressur

14、e, and the pressure at A point is:A, 63700, B, 66640, C, 69580, D, 607607. The water in the lower part of the closed container is air, and the upper part is air. The pressure measuring tube 4.2 meters below the surface of the liquid is 2.2M, and the local pressure is 9800Pa, and the absolute pressur

15、e of the liquid level in the container is the water column.A, 2m, B, 1M, C, 8m, D, -2m8. use U mercury manometer to measure A point pressure, and the vacuum value of A point isA, 63.70 B, 69.58 C, 104.37 D, 2609. in a sealed container, the lower part is water with density, the upper part is air, and

16、 the air pressure is p0. If the container falls free from the stationary state, the water in the vessel is h deep at the point of descent:A, B, C, 0 D,10. rectangular gate vertical water retaining and water pressure on the bottom of the gate is equal to the torque of the shaftA. B. C. D.11. a water

17、wheel is driven forward with equal acceleration a, as shown in the diagram, the angle between the free surface and the horizontal surface of the water wheel is equal to that of the water wheel12. rotating liquid at constant speedA, the piezometric head of each point is equal to the constant;The piez

18、ometric head of B and each point is not equal to the constant, but the height of the piezometric tube is equal to the constant;The pressure of C and each point is linear with the change of water depth;D and isobaric surfaces are not necessarily orthogonal to mass force.13. The cylindrical container

19、is filled with liquid and rotates around the Z axis at an equal speedA, B, C, and D,.14. for relatively balanced liquids,A and isobaric surfaces are not necessarily horizontal surfaces;B, the points on the same isobaric surface of the liquid, on the surface of the same depth of the free surface;C (f

20、or any);D, not set up.15. as shown in the picture, the water filled U tube rotates around the OZ axis at an equal speed. The depth of the I pipe is measured, and the depth of the II pipe is OA equals B equals;C, less than, D, between and.16. shows a cylindrical container with a radius of R with a de

21、nsity of liquid. If the vessel rotates around the OZ axis at an equal speed, the pressure at the A point isNo more than D.17. for relatively balanced liquids,A and isobaric surface are not orthogonal to mass force; B and isobaric surface can not be horizontal surface;The shape of C and isobaric surf

22、ace is related to the density of liquid. The interface of D and two liquids is isobaric surface.18. as shown in the figure, the constant speed w rotating container with a radius of R and a liquid with a density of R, then rotates the bottom pressure distribution of the container before and after rot

23、ationA and the same; B is not the same; C, equal; D, inequality.19. try to explain, for example, the relative balance of the liquid, under what circumstances?,A, B,;C, D,.20. in an upright vessel rotating at an equal speed, the pressure distribution in the liquid relative to the equilibrium isA, B,;

24、C, D,.Which is the surface pressure; the depth at which the point of calculation is below the coordinate origin; R is the distance from the point to the axis of rotation.21. liquid by surface pressure after P, it will _ transfer to the liquid inside a.A does not change; B increases; C decreases; D t

25、ransfers pressure only and does not transfer pressure22. who come into contact with water _ called compression surface.A, plane, B, curved surface, C, wall D and underside23. static water only by gravity, the piezometric head line will be _.A, horizontal line, B, straight line, C, oblique line, D an

26、d curve24. in homogeneous connectivity in static liquid, the pressure on any _ necessarily equal.A, plane, B, horizontal plane, C, inclined plane; D and above are not correctOne side of the hydrostatic pressure and _ static liquid is proportional to the 25.A, submergence depth; B, position height; C

27、, surface pressure; D and above are not correct26. arbitrary plane on the wall of the hydrostatic pressure is equal to _ at hydrostatic pressure multiplied by the compression surface area.A, the center of gravity, B compression; compression surface; C, D, compression compression face centroid; the o

28、rthocenter;27. the relation between the isobaric surface and the mass force is.A, parallel B, skew C, orthogonal D, independent28. The relative pressure at 5m in the open water pool is:A, 5kPA, B, 49kPA, C, 147kPA, D, 205kPA,29 straight rectangular plate retaining water, water depth 3M, static water

29、 pressure P point of action, the distance to the water surface y:A, 1.25m, B, 1.5m, C, 2m, D, 2.5m30. uniform flow isA, the local acceleration is zero, the B and the migration acceleration are zero;C, the centripetal acceleration is zero, D, and the resultant acceleration is zero31. variable diamete

30、r tubes, diameter D1=320mm, D2=160mm, flow velocity v1=1.5m/s, V2 forA, 3m/s, B, 4m/s, C, 6m/s, D, 9m/s32. what is the change of the total head line of viscous fluid?:A, along the decline of B, along the rise of C, maintain the level of D, the first three are possible33. the variation of the head li

31、ne of a viscous fluid pressure gauge is:A, along the decline of B, along the rise of C, maintain the level of D, the first three are possible34. variable head contraction pipe flow:A has local acceleration and migration acceleration, and B has local acceleration without moving acceleration;C, there

32、is migration acceleration, no local acceleration, D, no acceleration35. the following description is correct:A and constant flow must be uniform flow; B and three dimensional flow can not be uniform flow;C and constant flow streamlines and traces do not necessarily coincide; D and constant flow must

33、 be one yuan flowThe third chapter is about the basis of one-dimensional fluid dynamics1. differential equations of Euler motion: the dimensions of each areA, stress, B, energyC, acceleration, D, the above answer is wrongThe mathematical description of 2. Euler differential equations at each point i

34、s:A, the incoming mass flow is equal to the mass flow rate B, and the mass force is equal to accelerationC, energy does not change with time, D obeys Newtons second law3. water flow in a certain direction should beA, from high to low;B, from large to small flow pressure pressure;C flow from a large

35、velocity to a small velocity;D from a unit weight, fluid, mechanical energy, high place, to a low place.4. when the ideal fluid flows through the pipe and suddenly amplifies the section, its piezometric head line ()A, only possible to rise; B, only possible to decrease;C, only possible level; D and

36、above three situations are possible.5. when applying the energy equation of constant total flow, the cross section of the graph can be chosen as the calculated section.A, 1, 2, 3, 4, 5, B, 1, 3, 5, C, 2, 4, D, 2, 3, 46. the water pump pipeline system, section 2-3 respectively outlet of the pump sect

37、ion, calculation formula for pump lift:7., the known diameter of the siphon pipe downstream is submerged outflow, as shown in the section, the absolute value of the pressure head, or vacuum, then the formula is ()The 8. is provided with a constant shunt, as shown, according to the total flow Bernoul

38、li equation, which can be listed ()9., the total flow energy equation is used for compressible, negligible gasesIn the following discussion, the correct person is ()The relative pressures of the first and two sections are A and respectively;B, and the absolute pressure of the first and two sections,

39、 respectively;The relative pressure or absolute pressure of the corresponding section of the C does not affect the calculation results;D, the equations above apply only to liquids, not to gases.10., respectively, of the total energy equation for incompressible gas flowAbsolute pressure at the A, 1 a

40、nd 2 sections;The absolute pressure on B and 1 sections and the relative pressure at the 2 section;Relative pressures on the C, 1 and 2 sections;The relative pressure on D and 1 sections and the absolute pressure at the 2 section.11. when the air density is greater than the density of the gas and th

41、e gas flows from the 1 section at the lower to the 2 cross section, the representative of the total energy equation of the gas flowA, the potential energy lost by a unit weight gas in the course of flow;B, the potential energy of a unit weight gas in the course of flow;C, the potential energy that a

42、 unit volume gas loses in the course of flow;D, the increase of potential energy per unit volume of gas in the flow process.12. when the incompressible gas flows, the following statement is correct as ()A, the total pressure line, the potential line and the pressure line always go down along the way

43、;B, pressing, pressing and pressing a potential may have dropped along yousheng;C, the total pressure line and the pressure line always go down along the way, and the potential pressure line may rise or fall along the course;D and the total pressure line always go down, and the potential line and po

44、sition line may rise or fall.A water tank 13 jet from the pipe outlet vertical line flow on the scales, the side wall of the water tank orifice flow while maintaining constant water level, water and heavy weight for a total of G box, if the outlet flow rate is Q and the exit velocity, water jet velo

45、city for the shares, as shown, then the weight scale readings the ()A, G, B, C, D,14. jet from the diameter of D of the circular nozzle at the speed of V injection, impact on the export angle of the axisymmetric curve on the blade, the blade movement speed is u, as shown. If the frictional resistanc

46、e and head loss are neglected, the impact force of the jet on the moving blade is ()A, B,C, D,15. set a water pump in the sink, as shown. The pump returns water to the smooth plate and then falls back into the tank. Known as the D nozzle diameter, jet velocity, flat angle, jet into the sink angle, i

47、f the friction energy loss, air resistance, and the ground wheels are neglected, the direction of movement is the sink is initialA, Xiang Zuo; B, right; C, stationary; D; not sure.16. a fire gun to speed to the horizontal distance of 30m, high 30m fire water points, when the minimum elevation for th

48、e gun (), water can reach the destination.A, B, C, and D,.17. water injection nozzle by level, impact on fixed vertical plate, nozzle diameter, jet flow, friction resistance and without air on the jet jet and tablet, is equal to the impact force of flat jet;18. the actual fluid flows in the pipeline

49、 of equal diameter, and the 1, 2 and 3 points on the over current ground have the following relationsA, B,C, D,19. in the ideal incompressible incompressible steady flow, the velocity of the two points A, B and A at the same flow line is greater than the velocity of BPiezometric head of piezometric

50、head at A and A points B point;Piezometric head of piezometric head at B and A points B point, pressure head;D, A point, pressure head, B point, pressure head.TwentyVelocity and force in momentum equation:A, the flow velocity has direction, the force has no direction. B, the flow velocity has no dir

51、ection, and the force has direction.C, no direction. D, both directions.21. of the kinetic energy correction factor reflects the flow section of the actual velocity distribution non-uniformity coefficient, velocity distribution _, coefficient of _, when the velocity distribution of _, then the kinet

52、ic energy correction factor value close to _.A, the more uneven; the smaller; even; 1. B, the more homogeneous; the smaller; even; 1.C, the more uneven; the smaller; even; zero D, the more uniform; smaller; even; zeroThe fourth chapter is flow resistance and energy loss1. when the flow rate and wate

53、r temperature are constant, the Reynolds number Re of water flow increases with the increase of the diameterA, increase B, reduce C, constant D, indefiniteThe critical Reynolds number for the flow of 2. round tubes is (?)A, 300, B, 1200, C, 3600, D, 12000, E, these are notIn the 3. Reynolds experime

54、nt, the critical velocity of the transition from laminar to turbulent flow and the critical flow velocity from turbulent to laminar flow are (D) uncertainty4. the flow of water and air between two different fluids in a circular tube, the critical Reynolds number is ()A, water B, water air air. C, wa

55、ter = air D, depending on temperature and pressureThe Reynolds number Re of the 5. pipe flow is ()A, B, C, D, E, none of theseFormula: V; average velocity of section; D; diameter; n; kinematic viscosity; m; dynamic viscosity; R density.6. Reynolds number Re reflects the () contrast relationA, viscou

56、s force and gravity, B, gravity and inertia forceC, inertial force and viscous force, D, viscous force and hydrodynamic pressureIn the 7. pipe flow, the shear stress distribution on the cross flow section is ()The distribution of the shear stress on the cross section of the 8. round tube isA and parabola distribution, the pipe wall is zero, the pipe shaft is the biggest;B and straight line distribution, the maximum pipe wall, the tube axis is zero;C, uniform distribution;D, laminar flow is parabola distribution, and turbulent flow