查询词典 vortex

It is shown from this thesis that flow fields on synoptic maps can be decomposed into rotation and deformation fields. Geostrophic non-frictional cyclone and anticyclone vortex patterns are closed circulations around the center point, streamlines of frictional cyclone and anticyclone patterns have spiral forms around the focus point. Saddle fields have four vortex centers (two cyclones and two anticyclones) and a saddle point. Blocking high pressure and cut-off low pressure patterns consist of a vortex center and a saddle point.

本文说明了天气图上的流场可以分解为旋转场和变形场：地转无摩擦的气旋、反气旋的涡旋型式是围绕中心点的闭合环流；考虑摩擦的气旋、反气旋的流型是围绕焦点的螺旋型式；鞍型场有4个涡旋中心点（2个气旋和2个反气旋）与1个鞍点；阻塞高压和切断低压由1个涡旋中心点与1个鞍点组成。

In chapter 1, an up to now synthetically evaluation is given on the research ways and conclusions about jet in cross-flow. Considering the shortage of previous research ways and techniques (the instantaneous flow field and vortices field can not be properly get), in addition to the deficiency of corresponding conclusion (mainly concentrate on the analysis of time-average but little on structures of flow and action of vortex), the research way and content is draft out in this part. Though PIV, the time-average, instantaneous flow field and vortices field can be get, that will unveil the coherent vortex and its course of generation, development and evolvement, with the assistance of K-ε model and Hybrid Finite Analytic Method , which will proof-test the experiment result and bring some complementary, more profound research about the 3-D characters can be done. Using some fundamental topological theory and principle on flow analysis, with anglicizing of vortex structure, a reasonable description is the topological characteristic of near field in JICF given.

首先在第一章中对横流中湍射流的以往研究方法和研究成果给予了综合的评述，针对横流中湍射流旋涡结构以往研究中研究方法的局限性（不能很好得到流动的瞬态流场及涡量场）和相应研究成果中存在的不足（大都集中在时均特性的分析，对流动的内部结构和旋涡的运动阐述很少），明确了本文的研究方法和研究内容：通过PIV流动测量显示技术得到流动的时均及瞬态流场、涡量场，来揭示横流中湍射流的时均、瞬态流场、涡量分布特性，和各种具有拟序结构性质的复杂涡系的产生、发展及演化过程；结合湍流k-ε双方程模型及相应的HFAM计算方法，对于实验进行相互验证和补充，从而更为充分地研究各种旋涡的三维特性；利用拓扑分析的一些基本原理及相关规则，依据对各种旋涡结构的分析，做出对射流近区流场拓扑性质的合理描述。

For vortex-liquid phase,the E-J relation could be described according to the Kim-Anderson model:U=U0(1-J/JC).While for vortex-glass phase,the electric field decays verydramatically with decreasing current density,so it is difficult to be observed with theinstrument has limited precision.In the intermediate current region,the E-Jrelations of the both phases could be fitted in terms of a phenomenological model:U=(U0/μ)[μ-1],it was concluded that the sign of μ-value changes fromnegative to positive when the temperature decreases lower than the glass-transitiontemperature Tg,meanwhile,the activation energy U enhances dramatically.Whilein the large current region,Zeldov's logarithmic model was suitable for fitthing theE-J curves of the both phase.Moreover,there was no abrupt change of U or thecharacteristic current density IC.However,the effective radius of vortex line variesremarkably around Tg.

对于涡旋液体相，小电流区的E-J关系可以用计及反跳的Kim-Anderson模型U＝U0(1-J/JC)来描述，而对于涡旋玻璃相，小电流区的电场随电流密度减小而迅速衰减，以致很快脱离了实验测量精度的范围；在中等电流区，两相的E-J关系可以用共同的唯象过渡模型U＝(U0/μ)[μ-1]来拟合，得到在玻璃转变温度Tg两侧μ值由正到负的变化，同时激活能U在Tg以下迅速升高；在较高电流区，两相的E-J关系可以很好的用Zeldov对数模型来描述，拟合结果表明U在Tg两侧的趋势没有明显变化，但是涡旋线的有效半径发生了显著变化。

Compressed Air circumrotate at a high speed in the vortex tube, divided into two different airstreams after vortex in the vortex room, the air in the center of the tube have low temperature, and the air temperature out of the tube higher, adjust the rate of air in cooled and hot, we can get better refrigeration effect and hot effect.

气流在涡流管内高速旋转时，经过涡流变换后分离成总温不相等的两部分气流，处于中心部位的气流温度低，而处于外层部位的气流温度高，调节冷热流比例，可以得到最佳制冷效应或制热效应。

Based on analysis of the current state of the flow pattern modeling abroad and at home, explains the meaning of the mathematical simulation of the flows in the valve.(2) Comparing flow simulation data of jet pump with its experimental one, the feasibility and reliability of FLUENT used for flow simulation are proved.(3) Based on the characteristic of valves, the fluid field analysis of specific ring-spray type flow-adjustable is finished. The valve structure is optimized to meet the need, which makes it have such advantages:(1)smaller vortex area and faintish vortex intensity, so the vibration of vortex is controlled effectively;(2)the pressure is distributed more equality, the transition area is larger.

论文的主要内容包括：(1)简述了阀门研究的现状与发展，在分析与总结国内外流体流动模拟研究的基础上，探讨开展阀门内水流运动数值模拟的意义；(2)对特定型号的射流泵进行了内部流场的数值模拟研究，并与实验数据相比较，验证了应用Fluent进行数值模拟的可行性和可靠性；(3)针对调流阀的特点，对特大口径环喷式流量调节阀进行流场计算，其设计指导思想如下： 1、控制旋涡，减小旋涡区，减小涡的强度； 2、控制压力分布，使阀体受力更均匀，改善局部应力状态，提高阀门使用的安全性； 3、最小绝对压力高于水的汽化压力，不产生汽蚀。

We have got the following conclusions from the simulation in the thesis:(1) In even diameter hole, the tangental velocity has the characteristic of combination vortex; with the boundary of points for maximal speed, the insides is norm forced vortex, the outside is norm free vortex; the axis symmetry of tangental velocity is very well.

等直径工件孔内的螺旋流场，其切向速度分布具有组合涡的特点，以最大切向速度点形成的面为界，内部是强制涡，外部是自由涡，其轴对称性很好。

In this paper, The delta wing of Mach number 0.8 at an attack angle of 21. 8 degree is simulated by our program. Then, using the visualizing program, we map the figures of space streamlines, cross streamlines near the vortex axis, three dimensional vortex lines, cloud atlas for pressure and vortex and targer of particles.

在这一章里，我们先用所建立的计算软件数值模拟了来流马赫数为0.8、攻角为21.8°的三角翼的流场，之后以拓扑分析结果做指导，研制了一套数值显示流场、旋涡结构的软件，用该软件我们绘制了跨音速三角翼背风区涡轴附近截面流线、空间流线、三维涡量线、压力和涡量云图以及粒子屏痕图。

The results show that for a supersonic shear layer without reaction, a disturbance can make the shear layer become unstable, this results in one vortex or more than one vortex. The combination and seperation of vortex can intensify the mixing. But it is not easy for supersonic reacting shear layer with exotherm to become unstable with disturbance, and the effect duration is very long.

结果表明，对完全气体的超声速剪切层流动，一定的激励方式能使原先较为稳定的剪切层流动变得不稳定，产生单涡或多涡结构，发生多涡间的合并，使混合加剧；但对于存在放热现象的反应超声速剪切层流动，外加激励方式不易使流动从稳定变为不稳定，而且外加扰动的作用特征时间也较长，实际应用前景不乐观。

It relies on two vortex plate to work with each other movements which has a very high machining accuracy and mutually gearing, in which one fix on the machine rack, called the static vortex plate; the other is driven by the partiality shaft to move around the static disk base circle center , called the moving vortex plate.

它是依靠加工精度很高且相互啮合的两个涡盘的相互运动而工作的，其中一个固定在机架上，称为静涡盘；另一个由偏心轴驱动绕静盘基圆中心平动，称为动涡盘。

After analyzing the performance anduncertainty of the DDPM vortex flowmeter in gas-liquid bubble flows, the vortexflowmeter-Venturi tube combinative method using the vortex flowmeter and the Venturi tube as measuring cells was put forward, the measurement model based on thevortex frequency and the Venturi differential pressure was established, and it showsthat the relative errors of this method for the mass flow measurement of bubble flowsare within±5%. Furthermore, the flowrate and volume void fraction of bubble flowswere obtained using a single DDPM vortex flowmeter through the relationshipbetween the frequency and amplitude of the circumferential DDPM signal, and resultsdemonstrate that the relative errors of the flowrate and volume void fraction of bubbleflows are within±5% and±10% respectively, which indicates the broad applicabilityof this method to large numbers of engineering fields.

通过分析管壁差压式涡街流量计在气液泡状流中的性能和不确定度，提出了以涡街流量计和文丘里管作为测量元件的&涡街—文丘里联合法&，建立了以涡街频率和文丘里差压为被测量的测量模型，该方法对气液泡状流质量流量的测量相对误差可达±5％；通过建立涡街周向管壁差压信号频率和幅度与被测流体的关系，使用单个涡街流量计实现了对气液泡状流流量和体积含气率的双参数测量，该方法对气液泡状流流量和体积含气率的测量相对误差分别为±5％和±10％，可以满足大量工业实际应用的要求。

In the days of sailing vessels the crew were afraid they would be becalmed on the ocean.

在使用帆船的时代，船员们担心他们会因为无风而无法在海洋上航行。

As long as foreign donors pay the PA's salary bill, few expect a new intifada.

只要外国继续为巴权力机构的薪水买单，希望发动新暴动的人便寥寥无几。