流

The number and distribution of the singular points of streamlines in the cross section of steady flow through a curved tube are discussed by using the method of topological structure analysis.

利用拓扑结构分析方法，分析了弯曲圆管内定常流在横截面上流线的奇点个数及分布规律，给出了二次流的漩涡数目由 2个变为 4个，流态结构发生分叉现象的理论判据·进而，利用Galerkin方法，得到了弯曲圆管内定常流的流函数和轴向速度的半解析表达式，给出了流态结构发生分叉现象的临界Dean数，所得结果与理论判则一

Numerical simulation to three-dimensional turbulent flow in multistage axial compressor blade row is carried out, where high resolution third-order ENN scheme is adopted to catch the shockwave and simulate the turbulent flow correctly, and LU-SGS implicit method is chosen to improve computation rate. A nicety and high efficiency numerical simulating system is thus constructed.

对多级轴流压气机叶栅内三维紊流流场进行数值模拟，采用高精度高分辨率的三阶ENN格式以保证对激波的捕捉和对紊流特征的正确模拟，利用LU-SGS隐式解法提高了计算速度，从而构成了一种既准确又高效的多级跨声速轴流压气机紊流流动数值求解系统。

Seepage velocity smoothly change from a steady value to a new steady value, the ratio of the new steady value over the original steady value might increase hundreds of thousand times or even more, but it is always finite.（3）Water-inrush goes with the failure of rock strata, but seepage velocity can not increase unendingly, so seepage flow cant be unstable.

研究表明：由于非Darcy流β因子恒为正值，渗流系统总是稳定的；当渗透特性随时间变化时，渗流速度从一稳定值平滑地过渡到一新的稳定值，新的稳定值与原稳定值之比可以增大到几万至几百万倍，但是总是有限的；突水是岩层结构破裂引起的渗流速度快速或急剧变化，但渗流速度不可能无止境地增大，即渗流不可能失稳。

The fluid flows and heat coupled calculation method is used. The standards two equations turbulence models, velocity and pressure coupled arithmetic are used.According to the results of numerical simulation analysis the local coefficient distribution changes along the pin fins.Study the effection that its height and shape of the pin fins have on the average Nu and the average number of pressure loss coefficient Eu.The circle-shaped and elliptic-shaped pin fins have different circumcolumnar regional,therefore the mixed conditions are effected.

数值计算中采用标准双方程湍流模型，速度压力耦合算法；根据数值模拟的结果分析沿扰流元的局部换热系数分布变化，研究其扰流柱高度及形状对扰流柱通道平均努赛尔特数Nu和平均压力损失系数Eu的影响，圆形和椭圆形扰流柱的绕流尾涡影响的区域的不同对扰流柱群内流体混合状况的影响。

In this paper,the condition that gas flow through wood in the pattern of linear flux wasdetermined from the theories of thermodynamics and fluid mechanics.The expression of flow-resistor of tracheids is reduced with the continuity equation and the equation of motion indifferential form.The flow-resistor network is constructed by means of the theory ofpercolation.The equivalent flow-resistor was evaluated by utilizing the real spacerenormalization approach.

本文根据针叶材管胞的解剖结构，运用孔隙介质流体力学的理论，导出了管胞关于气体渗透流阻的数学表达式；继而根据管胞纹孔在三个纹理方向上的连接特性，利用管胞流阻建立了一个描述针叶材三个纹理方向气体渗透性的三维流阻网络；然后运用实空间重整化变换的方法，求解试件流阻网络三个纹理方向的等效流阻，并由此计算试件相应的气体渗透系数；最后用我国南方常见的人工林马尾松木材试件进行渗透系数实际测量，与理论计算结果进行对比分析，以验证三维流阻网络及其理论的准确性。

The calculation results shows that ,(1) when the rotor rotates at the working speed, a local regurgitant whirlpool that is rightabout to the rotor"s rotating direction appears in the classifying region, which makes the separated granules come back to the outside of the classification district and influences the classification efficiency of the turbine classifier;(2) in the condition of a low rotating speed of turbo rotor, ultrafine particles can follow the gas phase by and large, but when the rotating speed increases, a phenomenon of velocity slippage between two phases appears evidently;(3) A operating parameter, air flow rate is so important that can directly influence the stability of flow field in classifying chamber, the bigger the air flowrate is , the steadier the flow field is;(4) Compared with straight blades, the new shape of blades with backward crooked elbow are helpful to improve the stability of flow field and form whole stream easily, also beneficial to advance the classification accuracy and classification efficiency;(5) The motion trace of particles are very complicated when the turbo rotor rotates at a high speed, the constant bounce of the particles appear between the blades and the coarse particles are even bounce back from the inlet, only the finer can pass through the classification area from the oulet;(6) Along with the increase of the rotor"s rotating speed, radiah axial and tangential velocity all begain to fluctuate repetitively like sine-wave, the smaller the particles are, the more violently they fluctuates.

数值模拟结果表明，(1)在涡轮达到工作转速时，在分级区域形成了一个与涡轮旋转方向相反的局部回流涡，它使得分离出来的细粒重又被带回分级轮外边缘，从而严重影响分级机的分级效率；(2)粉尘粒子在涡轮低速运动情况下，基本上能跟随气体运动，但随着转速加大，两相之间出现了明显的速度滑移现象；(3)分级机工作时的风量也是一个比较重要的操作参数，它可以直接影响到分级机内腔流场的稳定性，风量越大，流场越稳定；(4)同直叶片形状相比较，带后弯导板的叶片，有利于改善流场的稳定性，流场容易形成整体流，对提高分级效率和分级精度都非常有利；(5)粒子轨迹线在涡轮转速较高时十分复杂，有的出现了反复的弹跳现象，大颗粒不能通过分级区域而从进口返流了，只有细小的颗粒才从出口处流出；(6)涡轮转速加大时，粒子的径向、轴向和切向速率出现了明显的类似于正弦波的脉动现象，颗粒越小，脉动程度越为剧烈。

The flow characteristics in the flow path of emitters must be understudied roundly in order to design an emitter with high performances.But the labyrinth path was very narrow and complex,and the archetype experiment of the emitters was unreasonable both in the technology and...

通过对迷宫式流道内部流体流动特性的分析，构建了表征迷宫式流道内部流动的数学物理模型；对所选取的目前中国农业灌溉领域最为典型的三种圆柱型灌水器，借助FLUENT6.1 CFD流场软件分析平台实现了流道内部流速分布、涡量分布、紊流强度分布等流动特性的可视化，为新型灌水器流道研制提供一定理论基础。

Based on the detailed study of seismic tomography image in South China, and according to the geotectonic environment and shape and heat of asthenosphere upwelling, we divided the structure of lithosphereasthenosphere at the Mesozoic upper mantle of Eastern China into three types.(1)Continental platform area (North China platform and Yangtze platform): asthenosphere upwelled along paleorift; over the plume head, the granitic rocks of crust and mantle mixed and correspondingly, Au, Cu, Mo, PbZn, etc. mineralizationconcentrated regions were formed; and at the steep contact belt of asthenosphere and the thick area of lithosphere, mediatebasic complex was formed.(2)Central area of fold zone: asthenosphere was "recumbent" at suitable depth, with adequate heat and in a great extent; by heat conduction, the interior of partial crust remelted, and the crustsource granitic rocks, and correspondingly, W, Sn and rare elements mineralizationconcentrated regions were formed.

在深入研究华南地震层析成像的基础上，按照大地构造环境和软流圈上涌形状和热度，将中国东部中生代上地幔中岩石圈软流圈构造划分为3类：(1)陆台区，软流圈沿古裂陷上涌，其柱头上方形成幔壳混熔花岗质岩及相应Au、Cu、Mo、PbZn等矿集区，并于软流圈与岩石圈厚区之陡接触带形成中基性杂岩及相应Fe矿集区；(2)褶皱带中心区，软流圈在适当深度、热量充足、较大范围内&平卧&，因热传导而致使地壳内物质部分重熔，形成壳源型花岗质岩及相应的W、Sn、稀有元素矿集区；(3)褶皱带边缘区(大兴安岭南部及华南南缘)，在软流圈上涌柱上方形成幔源或幔壳混熔的花岗质岩，相应为Cu、Au、PbZn、Mo、Ag矿集区。

This study choose Changle Gaoya reservoir irrigation areas as the study sites, through the installation of different ultrasonic equipment on open channel of non-uniform flow to study the flow gauging of non-uniform flow in open channel:(1)5 tracks ultrasonic open channel flow meter used to real-time monitoring the flow of velocity ,water depth and discharge;(2)Ultrasonic liquid level gauge used to real-time measure the upper level and tail level of the two sections ,then the computer calculated average water level, gradient of water table and discharge;(3)Change the open channel water conveyance into pipeline full flow water conveyance, installed the ultrasonic liquid level gauge and pipe flow gauge on the inflow point and surface of pipe, water level and discharge would detect in real time.

本研究以山东省昌乐县高崖水库灌区为研究地点，通过安装在灌溉明渠上的不同超声波设备对明渠非均匀流的测流进行了研究：(1)用五声波超声波明渠流量计对测流渠段的流速、水深及流量进行了实时监测；(2)用超声波液位计将测流渠段的上下游两断面水位实时测出，再用计算机分时段算出平均水位、水面坡降及流量；(3)将测流渠段明渠输水改造成管道满流输水，分别在管道进口前及管管上安装超声波液位计和管道式流量计，将水位和流量实时测出。

The particles with heavy specific gravity are discharged from the underflow mouth and those with light specific gravity are discharged through the overflow pipe and thus it realizes the separation for heavy and light particles.

流体自旋流器上端给入并在旋流器内形成强制旋转流，旋转流将颗粒按粒度和比重分为内外环层，当矿浆流动至锥体部分时，由于锥体的突然变向，阻力增大，颗粒群向下运动的趋势减缓，并在此形成旋转悬浮层，随着离心力场的减弱，重力作用越来越明显，由按粒度和比重分成的内外两层逐渐转化为按比重分选的上下两层，比重大的颗粒通过底流口排出，比重小的颗粒则通过溢流管排出，从而实现轻重颗粒间的分离。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。