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专业好文档沈阳广播电视大学流体力学大作业学 校: 专 业: 分 校: 姓 名: 教育层次: 学 号: 一、 选择题1. 牛顿内摩擦定律适用于()。A任何流体 B牛顿流体 C非牛顿流体 2. 液体不具有的性质是()。A易流动性 B压缩性 C抗拉性 D粘滞性3. 连续介质假定认为流体()连续。A在宏观上 B在微观上 C分子间 D原子间4. 在国际单位制中流体力学基本量纲不包括()。A时间 B质量 C长度 D力5在静水中取一六面体,作用在该六面体上的力有()A切向力、正压力 B正压力 C正压力、重力 D正压力、切向力、重力6下述哪些力属于质量力 ( ) ( ) A惯性力B粘性力C弹性力D表面张力 E重力7某点存在真空时,()()A该点的绝对压强为正值B该点的相对压强为正值C该点的绝对压强为负值D该点的相对压强为负值8. 流体静压强的()。A方向与受压面有关 B大小与受压面积有关C大小与受压面方位无关9. 流体静压强的全微分式为()。A B C10. 压强单位为时,采用了哪种表示法()。A应力单位 B大气压倍数 C液柱高度11密封容器内液面压强小于大气压强,其任一点的测压管液面()。A高于容器内液面B 低于容器内液面 C 等于容器内液面12流体运动的连续性方程是根据( )原理导出的。A.动量守恒 B. 质量守恒C.能量守恒 D. 力的平衡13. 流线和迹线重合的条件为( )。A.恒定流 B.非恒定流 C.非恒定均匀流14. 总流伯努利方程适用于( )。A.恒定流 B.非恒定流 C.可压缩流体15. 总水头线与测压管水头线的基本规律是:( )A.总水头线总是沿程下降的。 B.总水头线总是在测压管水头线的上方。C.测压管水头线沿程可升可降。 D.测压管水头线总是沿程下降的。16. 管道中液体的雷诺数与( )无关。 A. 温度 B. 管径 C. 流速 D. 管长17. 某圆管直径d=30mm,其中液体平均流速为20cm/s。液体粘滞系数为0.0114cm3/s,则此管中液体流态为( )。A. 层流 B. 层流向紊流过渡 C.紊流18.等直径圆管中紊流的过流断面流速分布是 ( )A呈抛物线分布 B. 呈对数线分布C.呈椭圆曲线分布 D. 呈双曲线分布19.等直径圆管中的层流,其过流断面平均流速是圆管中最大流速的( )A 1.0倍 B.1/3倍 C. 1/4倍 D. 1/2倍20.圆管中的层流的沿程损失与管中平均流速的( )成正比.A. 一次方 B. 二次方 C. 三次方 D. 四次方 21.圆管的水力半径是 ( )A. d/2 B. d/3 C. d/4 D. d/5.22.谢才公式中谢才系数的单位是( )A. 无量纲 B. C. D. 23. 判断层流和紊流的临界雷诺数是A.上临界雷诺数 B.下临界雷诺数C.上下临界雷诺数代数平均 D.上下临界雷诺数几何平均 24. 对于管道无压流,当充满度分别为( )时,其流量和速度分别达到最大。A. 0.5, 0.5 B. 0.95, 0.81 C. 0.81, 081 D. 1.0, 1.025. 对于a, b, c三种水面线,下列哪些说法是错误( )A所有a、c型曲线都是壅水曲线,即,水深沿程增大。B所有b型曲线都是壅水曲线,即,水深沿程增大。C所有a、c型曲线都是降水曲线,即,水深沿程减小。D所有b型曲线都是降水曲线,即,水深沿程减小。二、判断题1.压强和切应力属表面力。( ) 2.流体惯性力与加速度方向相同。( ) 3.粘滞性可以制止流体流动。( ) 4.理想流体与实际流体的区别仅在于,理想流体具有不可压缩性。( ) 5.等压面与质量力垂直。( ) 6.某点存在真空,是指该点的绝对压强小于大气压强。( ) 7. 静止流体中某点压强的大小,不仅与其淹没深度有关还与受压面的方位有关。( )8. 相对压强的数值可为正值,也可以是正值。( ) 9. 静止液面下的闸板的总压力作用中心与闸板形心重合。( ) 10. 和大气相通容器的测压管液面一定与容器内液面高度相同。( ) 11. 相对静止液体的等压面一定是水平面。( ) 12. 以每个流体质点运动规律为研究对象的方法称为拉格朗日法。( ) 13.恒定流一定是均匀流。( ) 14.涡流是指流体质点在运动中不绕自身轴旋转的流动. ( ) 15.无旋流就是无涡流。( )16.非均匀流一定是非恒定流。( ) 17.N-S方程为理想流体运动的微分方程。( ) 18.毕托管是量测流体点流速的一种仪器。( ) 19.层流的沿程水头损失系数仅与雷诺数有关。( ) 20. 壁面光滑的管道一定是水力光滑管。( ) 21. 在过流断面突变处一般发生局部水头损失。( ) 22. 等直径圆管中的层流,其过流断面平均流速是圆管中最大流速的1/2倍( ) 23.流体内切应力方向与流体运动方向相同。( ) 24.阻力平方区内阻力系数与雷诺数无关。( ) 25.计算阻力损失时,短管既要考虑局部阻力损失,也要考虑沿程阻力损失,长管计算同样也要考虑这两项损失。( ) 26.长管是指几何长度很长的管道。( ) 27.孔口淹没出流时,孔口淹没越深,其出流的流速和流量就越大。( ) 28.管嘴收缩断面的真空度与作用水头成正比,作用水头越大,收缩断面的真空度越大,泄流量也越大。( ) 29.同一短管,在自由出流和淹没出流条件下,流量计算公式的形式及流量系数 的数值均相同。( ) 30.若两孔口形状、尺寸完全相同,作用水头相同,一个为自由出流,一个为淹没出流,二者的流量是相同的。 ( )三、 简答题1为什么可将流体作为连续介质处理?2什么是流体的粘滞性?它对流体流动起什么作用?3动力粘滞系数和运动粘滞系数有什么区别?4 等压面是水平面的条件是什么?5 同一容器中装两种液体,且,在容器侧壁装了两根测压管。试问:图中所标明的测压管中液面位置对吗?为什么?6. 描述流体运动的两种方法是什么?简述其内容。7. 流体微团体运动分为哪几种形式?8. 写出恒定平面势流中流函数、势函数与流速的关系。9什么是过流断面和断面平均流速?为什么要引入断面均流速?10如图所示,水流通过由两段等截面及一段变截面组成的管道,试问:(1)当阀门开度一定,上游水位保持不变,各段管中,是恒定流还是非恒定流?是均匀流还是非均匀流?(2)当阀门开度一定,上游水位随时间下降,这时管中是恒定流还是非恒定流?(3)恒定流情况下,当判别第II段管中是渐变流还是急变流时,与该段管长有无关系?11. 说明总流能量方程中各项的物理意义。12. 写出实际流体恒定元流的伯努利方程和实际流体恒定总流的伯努利方程,并指出他们的区别? 13. 应用恒定总统能量方程时,为什么把过流断面选在渐变流段或均匀流段?14. 在写总流能量方程时,过流断面上的代表点、基准面是否可以任意选取?为什么?15. 关于水流流向问题有如下一些说法:“水一定由高处向低处流”;“水是从压强大向压强小的地方流”;“水是从流速大的地方向流速小的地方流”。这些说法是否正确?为什么?如何正确描述?16. 总流的动量方程为,试问:(1)中包括哪些力?(2)如果由动量方程求得的力为负值说明什么问题?17. 圆管中层流与紊流,其流速分布有什么不同?18. 简述尼古拉兹实验中沿程阻力系数的变化规律。19. 写出管流和明渠水流雷诺数的表达式,并说明其层流、紊流的判别标准?20. 雷诺数的物理意义?它为什么能用来判别流态? 21. 当输水管直径一定时,随流量增大,雷诺数是增大还是减少?当输水管流量一定时,随管径加大,雷诺数是增大还是减少?22. 两个不同管径的管道,通过不同粘滞性的液体,它们的临界雷诺数是否相同?23. 能量损失有几种形式?产生能量损失的物理原因是什么?24. 什么管嘴出流时,阻力增加了,泄流量反而增大?25. 写出薄壁小孔口出流的收缩系数,流速系数和流量系数的表达式。26. 外延管嘴正常工作的条件是什么?27.为什么外延管嘴出流比同等条件下孔口出流的流量大?28. 简述明渠均匀流的水力特征及其形成条件。29. 简述明渠水流的三种流态及其四个判别方法及标准。30. 简述明渠恒定非均匀流的水力特征四. 计算题 1、如图所示,A、B两条供水管道间安装一复式压差计测量管道压差,已知hAhB1.0,水银柱高差 h0.5m,求AB两点压强差( 水的密度1000kg/m3, 水银的密度H13.6103kg/m3) 2、如图所示,由三条不同管径的管段组成一条管路,水箱内水面恒定,已知d1=0.075m,d2=0.05m,d30.025m,三条管段的长度相等,均为10m,沿程损失系数1=23=0.02,管道进口局部水头损失为,B点处局部水头损失为 ,C点处局部水头损失为 ,并且1=230.5。(1) 求各管中的断面平均流速;(2) 求作用水头H(管中心至水面高差) 3、弧形闸门如图所示,门宽2m,其他尺寸如图, 求:a) 作用于闸门上的静水总压力; b) 总压力与水平面的夹角。 4、图示为一分叉管道位于同一水平面,已知d1=700mm,d2500mm A-A 断面压强pA=70kN/m2,管中流量Q0.6m3s,两支管流量相同。不计水头损失,求水流对镇墩的水平推力R=? 5如图所示,一封闭的容器中装有水,右侧安装一个U形管,U形管内水银H=13.6103kgm3,h2=0.85m,h1=0.4m,A点与水箱内水面高差为0.4m,求水箱内水面的相对压强p0。 6如图所示,一条管道,A、B两点的高差z=1.0m,A点处直径dA=0.25m,A点压强pA=78kNm2,B点处直径dB=0.40m,B点压强pB=4.9kNm2,管中流量Q=O.060m3s,试判断管中水流方向。 7某渠道建有一平板闸门排水闸,闸门与渠道同宽,门宽2m,当闸门在某一开度时,闸门前水深H=25m,闸孔后收缩断面水深hc=0.5m,闸孔出流局部水头损失为c-c断面流速水头的l2,即hj=0.5vc2/2g 求: (1)此时该渠道通过流量; (2)此时作用于平板闸门上的动水总压力(不计摩擦力)。 8图示离心水泵,抽水流量为Q=360m3h,吸水管长l=8m,管径d=0.25 m,沿程阻力系数=0.025,底阀局部阻力系数阀8.0,弯头局部阻力系数弯0.4,安装高度hs=3.0m。求:(1)求水泵进口2-2断面的相对压强; (2)若水泵进口2-2断面允许真空高度为hv=6.Om(水柱),该水泵安装是否合理? 9.水闸两侧都受水的作用,左侧水深3m、右侧水深2m。试求作用在单位宽度闸门上静水总压力的大小及作用点位置。 10. 如图所示,从水面保持恒定不变的水池中引出一管路,水流在管路末端流入大气,管路由三段直径不等的管道组成,其过水面积分别是A1=0.05m2,A2=0.03m3,A3=0.04m2,若水池容积很大,行近流速可以忽略(v00),当不计管路的水头损失时,试求:(1)出口流速v3及流量Q;(2)绘出管路的测压管水头线及总水头线。Winger Tuivasa-Sheck, who scored two tries in the Kiwis 20-18 semi-final win over England, has been passed fit after a lower-leg injury, while Slater has been named at full-back but is still recovering from a knee injury aggravated against USA.Both sides boast 100% records heading into the encounter but Australia have not conceded a try since Josh Charnleys effort in their first pool match against England on the opening day.Aussie winger Jarryd Hayne is the competitions top try scorer with nine, closely followed by Tuivasa-Sheck with eight.But it is recently named Rugby League International Federation player of the year Sonny Bill Williams who has attracted the most interest in the tournament so far.The Kiwi - with a tournament high 17 offloads - has the chance of becoming the first player to win the World Cup in both rugby league and rugby union after triumphing with the All Blacks in 2011.Id give every award back in a heartbeat just to get across the line this weekend, said Williams.The (lack of) air up there Watch mCayman Islands-based Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will attend Citys Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport.For me its about how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the racist behaviour of their fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also ordered an immediate investigation into the referees actions.CSKA said they were surprised and disappointed by Toures complaint. In a statement the Russian side added: We found no racist insults from fans of CSKA. Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunda.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.They blew it in 2008 when they got caught cold in the final and they will not make the same mistake against the Kiwis in Manchester.Five years ago they cruised through to the final and so far history has repeated itself here - the last try they conceded was scored by Englands Josh Charnley in the opening game of the tournament.That could be classed as a weakness, a team under-cooked - but I have been impressed by the Kangaroos focus in their games since then.They have been concentrating on the sort of stuff that wins you tough, even contests - strong defence, especially on their own goal-line, completing sets and a good kick-chase. Theyve been great at all the unglamorous stuff that often goes unnoticed in the stands but not by your team-mates.It is as though their entire tournament has been preparation for the final.In Johnathan Thurston, Cooper Cronk, Cameron Smith and either Billy Slater or Greg Inglis at full-back they have a spine that is unmatched in rugby league. They have played in so many high-pressure games - a priceless asset going into Saturday.The Kiwis are a lot less experienced but winning a dramatic match like their semi-final against England will do wonders for their confidence.They defeated Australia in the Four Nations final in 2010 and the last World Cup, and know they can rise to the big occasion.16
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