涡线

The main work and the originality points of this dissertation could be concluded as the following parts:(1) To analyze systematically the mathematical model of LES of air flow in great space, under the case of isothermal and non-isothermal, as well as the combined action of buoyancy and strain. Some basic problems are studied about the LES application into airflow simulation of great space, such as boundary conditions, spatial difference scheme and time advancing scheme, time step etc., which creates the basis for the LES application to indoor airflow simulation.(2) Both the instantaneous and time averaged flow field of great space with multiple jets under isothermal and non-isothermal cases are explored with large eddy simulation method, and also discussed the dynamic characteristics and the law of fluidflow in the great space.(3) Based on the results of LES of the great space and the Fanger thermal comfort indexes, it is brought forward the concept of the series of dynamic thermal comfort evaluating indexes, which could be divided into thermal comfort index with time averaged properties PD, PPD, PMV, thermal comfort index with instantaneous properties IPD, IPPD, IPMV, and time averaged thermal comfort indexes TAPD, TAPPD, TAPMV, and transient situations time averaged thermal comfort indexes TTAPD, TTAPPD, TTAPMV. The differences among them and the calculation methods are discussed, and the four kinds of indexes are calculated with the thermal comfort index PD as an example.(4) Based on the LES results it is discussed the hot air stratification phenomena in air-conditioned buildings in the case with air supply and return registers on the ceiling and the case on the sidewall. The fundamentals of the hot air stratification are studied and the relations of estimating hot air stratification are brought forward.(5) With the advanced apparatus such as hot wire film anemometer IFA300 and laser particle field anemoscope, corresponding model test and site measurements have been done, which are compared with the simulation results and LES is proved a very promising method in air flow simulation indoor.

本文主要工作既创新点体现在以下几个方面：(1)系统分析了等温、非等温和考虑剪切力与浮升力综合作用的高大空间大涡模拟数学模型，并研究了高大空间大涡模拟在室内气流仿真应用中的一些基本问题，如边界条件、空间离散格式和时间推进格式、时间步长选择等问题，为大涡模拟在室内气流计算中的广泛应用打下了基础；(2)首次用大涡模拟方法研究了高雷诺数下高大空间多射流在等温、非等温情况下的瞬时流场和时均流场分布，并探讨了多射流流场的动态特性和流动规律；(3)基于大涡模拟的动态仿真结果和Fanger的热舒适指标，首次系统地提出了动态热舒适评价指标体系的概念：即基于时间平均参数的热舒适指标PD、PPD、PMV；基于瞬时参数的瞬时热指标IPD、IPPD、IPMV；基于时间平均热舒适指标TAPD、TAPPD、TAPMV；以及沿行动迹线的时间平均热舒适指标TTAPD、TTAPPD、TTAPMV，并分析了四类热舒适指标的差异性和计算方法，还以PD值为例对四类指标分别进行了计算；(4)基于数十种工况下空调房间大涡模拟的结果，研究了空调建筑上送上回和侧送侧回两种情况下热分层现象，并探讨了热分层的基本规律，首次提出了避免热分层现象的判断公式；(5)在暖通空调领域，首次使用IFA300热线风速仪、激光粒子速度场仪等先进设备，完成了与大涡模拟相对应的模型试验，并把实测结果与仿真结果进行了对比，说明LES在室内气流仿真方面是一种很有前景的方法。

We used NCAR/NCEPT anew analyze data and the method of bilinearity insert to fix on profile distribution of several physical field in the air on observation point and the stream field of 700hPa. We primary discussed the possible mechanism to influence aerosol size distribution.The atmospheric condition of 1000hPa~700hPa level had great influence on aerosol size distribution, and influence on coarse particle mainly below 850hPa level. The horizontal wind velocity of 925hPa level is a primary gene which contributed to coarse particles in the air. Vorticity profile especially below 700hPa level is a key gene to influence diffuse and convergence of local aerosol. The air vertical motion velocity greatly influenced aggregation and remove of aerosol particles. The vertical distribution of air temperature mainly influenced vertical transportation of aerosol.

利用NCAR／NCEP逐日再分析资料，通过双线性插值方法，确定观测点上大气中几个物理量的廓线分布；及700hPa的流场，初步探讨了影响大气中气溶胶粒子谱分布的可能机制： 1000hPa～700hPa的大气状况对气溶胶粒子谱分布影响显著，对粗粒子气溶胶的影响显著的主要集中在850hPa以下；925hPa的水平风速是影响大气中粗粒子气溶胶的一个主要因子；涡度廓线(尤其是700hPa左右及以下的涡度廓线)是影响局地气溶胶的扩散的一个关键因子；大气的垂直运动速度对气溶胶的聚合及移出影响较大；大气温度的垂直分布主要影响气溶胶垂直输送。

Therefore, the moist potential vorticity analysis associated with the mesoscale convective system was researched in the paper, so as to reveal the moist potential characteristics of mesoscale convective system in typhoon circulation. The results showed that, during the generation stage, convective instability characterized by MPV1 was a favorable condition for forming MCS, while the vorticity which was caused by the slantwise isentropic surface and the vertical shear of the horizontal wind characterized by MPV2 was an inspiring mechanism. The specific process was that, the atmosphere exhibited the feature of strong convective instability at the low level of convection areas and the southeast areas, which included plenty of erratic energy. The slantwise ascended the stream transfer the erratic energy to northwest, where the stratification stability was small. As decreased, the cyclonic vorticity increased. On the other hand, the vorticity caused by the slantwise isentropic surface and the vertical shear of the horizontal wind inspired the release of convective instability and as a result that the MCS formed. During the development stage, the cyclonic vorticity increased quickly with the persistent decreasing of . Meanwhile, the inclination of isentropic linewas bigger than the absolute momentum line at middle level, which exhibited the feature of conditional symmetric instability , then the conditional symmetric instability was forced to release by the vorticity resulted from the slantwise isentropic surface and the vertical shear of horizontal wind, and the MCS developed.

结果表明，在对流形成阶段，MPV1即对流不稳定为MCS的形成提供背景不稳定条件，由MPV2即湿等熵面的倾斜和水平风的垂直切变而引起的涡旋发展作为强迫机制：MCS形成的区域及东南区域中低层是强对流不稳定层，蕴含丰富的不稳定能量，倾斜上升运动把对流不稳定区具有强不稳定能量的暖湿空气向西北中层的中性层结区输送，由于的减小，气旋性涡度增强，有利于形成对流，另一方面，由于湿等熵面倾斜和低空急流加强而引起的涡旋发展作为一种强迫机制激发对流不稳定能量得到释放，从而形成对流；在对流系统地发展阶段，由于低层的对流不稳定性进一步减弱，进一步减小，气旋性涡度进一步增强，有利于MCS的增强，中层等θe 线的倾斜度比绝对动量M 等值线的倾斜度大，对应有条件对称不稳定区域，满足条件对称不稳定条件，在湿等熵面倾斜和台风低空急流作用下引起的涡旋发展强迫对称不稳定能量释放，从而使得对流得以维持和加强。

Trapcode Form is a grid-based 3D particle system with a twist. It can be used to create fluid, organic patterns, complex geometric structures and swirling stringy animations.

Trapcode公司发布了基于网格的三维粒子插件FORM，它可以用来制作液体，复杂的有机图案、复杂几何学结构和涡线动画。

In the region upstream of vortex breakdown, the sectional streamlines emanating from the leading edge spiral inward to primary vortex and in the region downstream of the breakdown, on the other hand, the streamlines separating from the leading edge are not entrained into the vortex core in the instantaneous sense. Along the axis, the topology of the primary vortex alters several times starting from stable focus near the apex to unstable focus, and lasts back to stable focus near wake edge, the stable hmit cycle and unstable limit cycle are shown in this evolution.

发现在截面流线谱中，即使奇点的类型、数目及位置相同，奇点的连接方式也有可能不同；旋涡破裂点前，主涡由来自前缘的力线卷绕而成，主涡焦点与前缘半鞍点相连，旋涡破裂后，来自前缘的力线不再卷入主涡，主涡焦点与对称面上的鞍点相连：在流体由翼尖流向后缘的过程中，截面流线谱的拓扑结构发生了多次变化，主涡焦点相继由稳定状态转变为不稳定状态，最后又转化为稳定状态，并先后出现了稳定的极限环及不稳定极限环。

The results do indicate that there may be several mechanisms for asymmetric vortical flow.

本文结果表明了大迎角旋转体非对称涡的形成机理可能是多种的，即给定分离线位置不对称或自由涡线的个别线段不对称都能产生非对称涡流。

One of factors which activize the explosive development of cyclone exists strong convective instability in lower layers from the analysis of the barotropic potential vorticity.

气旋发展后期气旋中心上空300hPa以上位于位涡平流零线附近。850hPa以下的斜压位涡的正负值的变化与气旋的发展有很好的对应关系。

Then, a series of successful numerical simulations on the finite length inclined positively buoyant jets in uniform cross flows environment are developed. Based on the results from numerical simulations, some qualitative pictures of the complex three -dimensional mean flows are given. In terms of these pictures, the flowing behavior of the buoyant jets and the mechanism of end-vortexes generation are made a study. The change rules of end-vortexes and temperature and dilution on trajectory of jets, horse-hoof shape of buoyant jets on horizontal, the phenomenon of the jets touch wall, and the effects of diffuser length^ densimetric Foroude number % velocity ratio on buoyant jets are also given.

之后对均匀横流环境中的有限长线源型倾斜浮力射流进行了大量的数值计算，根据数值模拟的结果，绘出了一些复杂的三维图，据此探讨了其流动特性及端涡的产生机理，成功模拟了端涡现象及其发展过程，对轨迹线上沿程温度及稀释度的变化规律，倾斜浮力射流的马蹄形结构，浮力射流的贴壁现象，扩散器长度、喷口弗汝德数、流速比等对浮力射流的影响等问题均给出了有价值的结论。

Vortex lattice method is presented for calculating the loading distributions on all blades of propeller and hub which a number of small hyperboloidal quadrilateral panels are discreted.

螺旋桨采用离散涡环法，将桨叶表面和桨毂表面离散为一系列双曲四边形，在四边形网格中布置集中涡环和线源分布，根据物面条件建立方程得到涡和源汇分布的强度。

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。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。