对流

The effects of gap size, shape, inclination angle, pressure and form losses of two ends of annuli were discussed. Based on experimental data and theoretical analysis results, a new half-empirical correlation was also derived which can accurately predict the CHF of vertical annuli, circle tube and rectangular channel in a very wide range of H/De values.

在实验和理论分析的基础上，提出了一个新的，可用于计算竖直环隙、圆管及长方形流道内自然对流沸腾临界热负荷的半经验公式，其计算精度和适用范围较现有的计算公式有显著提高，原则上不受H/De值大小的限制。

Due to the complicated nature of the coupling processes between polar ionosphere and magnetosphere as well as thermosphere, however, here still remain lots of questions need to be further studied, such as the relationship between convection electric field and polar ionosphere, the mechanism of auroral particle precipitation, the origin of magnetospheric particles and so on.

如，极区电离层背景变化的气候学特征，对流电场与极区电离层的相互作用关系，以及极光区粒子沉降的机制和磁层粒子起源等等。

First of all, the factors which influence the thermal barrier effect and the relationship between the factors and heat resistance were analyzed. Then, the paper gave the mathematical model of the effect of thermal conductivity, coating thickness, environment temperature difference, and heat exchange coefficient on thermal barrier effect.

研究主要内容如下：本文首先分析了隔热效果的几种影响因素以及它们与隔热效果之间的关系，推导出了包含热障涂层厚度、导热系数、环境温差和对流系数等在内的影响因素与隔热效果之间的数学模型。

The result showed that the strong storm followed by mesoscale squall line was primary cause of strong sandstorm producing, steps and ladders short wave trough of 500 hPa was great criterion triggering system for the mesoscale squall line producing, the essential dynamic condition was provided by distortion field and the mesoscale low pressure of 700 hPa for the strong sandstorm forming and maintaining in mid-west of Hexi Corridor, the deep vertical circulation development condition was basic power that urged squall line to occur and sand dust to curl up, which was provided for the deep convection development by superimposition of lifting movement before ground cold front and ascendant current of secondary circulation in upper air jet entrance region, temperature and the barometric gradient around the cold front was enlarged by enhancement of ground thermal low and temperature diurnalvariation of afternoon, by which essential thermal energy unstable condition was provided for the gale and strong sandstorm eruption, the strong sandstorm appeared in downstream of -200 m^2s^(-2) center of vertical helicity, the vertical helicity had good instruction significance for development of squall line and landing region of sandstorm, the mesoscale squall line occurred in unstable stratification, basic condition of potential energy transforming as kinetic energy was provided by strong unstable stratification for the strong sandstorm forming and developing.

结果表明：中尺度飑线所伴随的强风暴是产生强沙尘暴的主要原因；500 hPa阶梯短波槽是中尺度飑线产生的大尺度触发系统，河西走廊中西部700 hp变形场、中尺度低压为强沙尘暴形成和维持提供了必要的动力条件；地面冷锋前上升运动与高空急流入口区次级环流的上升气流的叠加，为深对流发展提供了深厚的垂直环流发展条件，是促使飑线发生和沙尘卷起的基本动力；地面热低压的加强和午后气温的日变化加大了冷锋前后的温度和气压梯度，为大风、强沙尘暴爆发提供了必要的热力不稳定条件；强沙尘暴出现在垂直螺旋度为－200平方公尺/s^2中心的下游，垂直螺旋度对飑线的发展和沙尘暴的落区具有较好的指示意义；中尺度飑线发生在不稳定层结内，较强的不稳定层结为强沙尘暴形成、发展提供了位能转化为动能的基本条件。

In order to develop and modify Gregory scheme for cumulus convective parameterization,we make the improvement as follows:(1) The large-scale moisture convergence is taken into account and the organized inflow,which occurs in the area of large-scale moisture convergence and is directly proportional to it, is added to turbulent airflow.(2) The influence on saturation vapor pressure exerted by supercooled water is taken into account and the initial mass flux is adjusted. Based on diagnosis of the air heating and moistening, the downdraft airflow is adjusted.(3) Based on the character of our country heavy rainfall,which usually occurs in the mixed cloud consisted of stratocumulus and cumulus, the process of excessive convection is restrained by organized outflow in the top of cloud and improving downdraft current and by reducing the evaporation of rainfall and release of latent heat.

为了改进和发展Gregory积云参数化方案，(1)考虑了大尺度水汽辐合对积云对流的影响，即在混合卷入中加入有组织的卷入，让有组织的卷入存在于有大尺度水汽辐合的层次上，并且与大尺度水汽辐合直接成比例；(2)考虑了过冷水存在对饱和比湿的影响，调整了初始的质量通量，并且根据对大气加热加湿的诊断，调整了大气向下拖曳的强度；(3)根据我国降水多由层状云和嵌入其中的对流云混合产生的这一特点，对于过强对流过程进行抑制，在云顶加入有组织的卷出，同时加大向下拖曳的强度，减少蒸发以降低潜热的释放，抑制过强对流的发生。

Considing the complication of crenellated radial labyrinth geometry, a Taylor-Galerkin finite element scheme is developed to solve the multi-dimensional unsteady viscous convection-diffusion equation.

针对锯齿型迷宫密封几何形状的复杂性，发展了求解多维粘性非定常对流扩散方程的Taylor—Galerkin有限元法。

The physical character of the super-critical hydrogen in the regenerative cooling channel is studied : started with the physical character of the super-critical hydrogen , using the method of least square , figuring out the state equation which is applicable to the state from liquid to the super-critical in the super-critical pressure , the constrained convection and the heat transfer in the super-critical channel are simulated using the equation , the results of the simulation are identical with the experiment in the same condition .

对再生冷却通道内的超临界氢的物性进行了研究：从超临界氢物性的实验结果入手，用最小二乘法拟合出适用于超临界压力下氢由液态过渡到超临界态的状态方程，并利用该方程对超临界氢管内强迫对流换热进行了数值仿真，仿真结果与相同条件下实验结果相一致。

Water, as it comes in contact with different obstructions, can actually hold objects.

那些对流水运动动力熟悉的人知道当它接触到其他不同的阻碍物时，水可能会有困住物体的力量。

In this paper, the finite element method and the rotationally periodic analytical method are jointly employed to study the dynamics of fluid-structure coupling systems, the relevant analytical methods and program implement are provided.

本文采用有限元法结合旋转周期分析方法对流固耦合系统的动力性能进行了系统研究，给出了有关的分析方法和程序实现。

Based on a twodimensional model, smallscale convection in the upper mantlelithosphere system with variable viscosity is researched by using finite element method.

基于二维模型，利用有限元方法，研究上地幔-岩石圈系统的变黏度小尺度对流。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失