对流

It was shown that winter-time natural convection in the fractured-rock embankment began to occur in the side slope portions and developed from two side slope portions to the middle portion of embankment with lowering of surface temperatu...

通过引入自然对流指数，分析了自然对流降温效应随路堤碎石层填筑厚度的变化规律，其可分为恒零区、急增区和缓变区3个阶段，急增区的起点和终点对应于路堤碎石层填筑的最小厚度和最大厚度。最后，利用自然对流指数具体计算了不同粒径碎石层填筑的临界厚度。

Study of the causes of MCS intensification and rainstorm shows that( 1) just before the heavy rains occur, there are high temperature, considerably wetness and unsteady convective stratification in the air over the rainstorm-hit area, in addition to significant increase in convectively efficient potential energy, condensation height and decrease in the height of free convection – all these favor the happening of the heavy rain,(2) the mergence of meso-βcloud clusters leads to the MCS such fast growth as to produce rainstorm,( 3) the two lines of cumuli in the north and west correspond, separately, to two convergences on the surface wind field, with stronger convergence at their meeting point responsible for such intense development of meso-βcloud cluster as to bring about torrential rains.

分析MCS加强和产生暴雨的原因表明，首先，暴雨发生前夕暴雨区域具有高温、高湿和对流性不稳定层结，并存在明显的对流有效位能增加、抬升凝结高度及自由对流高度降低的现象，有利于暴雨发生。第二，β中尺度云团之间的合并，使MCS迅速增长，产生暴雨。第三，北、西两条积云线分别与地面风场中的两条辐合线相对应，在它们交汇处的较强辐合导致β中尺度云团强烈发展产生暴雨。

Main results are given as follows:(1) By means of the parameterization of convective gustiness, the mesoscale enhancement of surface fluxes is included in CAM3, thus, the parameterization scheme of sea surface turbulent fluxes in CAM3 is improved.

本文通过对流性阵风参数化方法，在CAM3原有海气湍流通量参数化方案(CAM3方案)中引入边界层自由对流和降水深对流对海表湍流通量的贡献，改进了CAM3模式的海气湍流通量参数化方案(CAM3 ME方案，简称ME方案)。

The parameterization scheme of sea surface turbulent fluxes in CAM3 (Community A tmosphere Model Version 3) was improved by the parameterization for win d gustiness, which considers the contribution to sea surface fluxes by the bound ary free convective and precipitation convective. The new parameterization schem e is named CAM3 ME scheme.

通过对流性阵风参数化方法，在CAM3原有海气湍流通量参数化方案(CAM3方案)中引入边界层自由对流和降水深对流对海表湍流通量的贡献，改进了CAM3模式的海气湍流通量参数化方案(CAM3 ME方案)。

Natural convection, natural wind and sun radialization bring the change of temperature. The most important factor is natural wind and sun radialization.

碎块石护坡和路基内的温度场受到自然对流、强迫对流和太阳辐射的影响，其中最主要的影响因素是强迫对流和太阳辐射。

By using the Eulerian-Lagrangian combined method, the convection-diffusion equation is spitted into the diffusion terms and convection terms. For convection terms, the implicit method of characteristics using time-line interpolation with high accuracy is adopted. While for the diffusion terms the conventional finite difference method is used.

采用欧拉—拉格朗日混合解法，将对流—扩散方程中的扩散项和对流项分裂求解，应用高精度时间序列插值的特征差分隐格式求解对流项，扩散项采用传统的有限差分法。

Evaluation shows that the method can separate most of the convective and stratiform cloud precipi...

试验表明，ACSS能较准确地实现对流性降水和层状云降水的自动分类，相对于只根据二维结构分类降水性能上有较大提高，主要表现在能正确识别出亮带特征明显的强层状云和对流核外沿的对流弱回波区。

This was because its flow velocity changed little in direction than the other one. However, the Z-like tube was a little better than the U-like tube when without blowing.

结果表明：不吹气时，管道结构对流场的影响远小于气体吸热对流场的影响；吹气时，管道内气体流速较大，管道结构对流场分布的影响比较明显；吹气时，U形管道对光束的影响比Z形管道对光束的影响要小。

In a same cloud band, the variation of temperature is small meanwhile the temperature is lower.The convective bubbles were observed in the warm clouds under the middle of the cumulostratus on 21,June 1992. The bubbles clearly show that they are one kind of mesoscale organization. It suggests that the synoptic system is situable to produce convective bubbles. Its contrastly analysed that the particle concentration and the liquid water content are higher.the particle spectra is similar,the particles captured by 2D-C probe are bigger in the bubbles.

1991年6月21日个例观测到对流泡位于层积云下部暖云中的部分，泡状结构明显，呈现出中尺度组织特征，天气系统的配置有利于垂直上升运动的发展：通过对比分析，发现对流泡内具有云滴浓度高、液态水含量较高、云谱型相似以及2D-C粒子尺度大等特点：本次个例观测到的对流泡内云滴谱表现为单峰型。

Evaluates the zero-equation model provided by Chen based on CFD simulation of three typical airflows(forced convection,mixed convection and natural convection)in air-conditioned and ventilated rooms.

为了对Chen提出的零方程模型进行评价，研究了三种典型的空调通风房间气流组织工况(强迫对流、混合对流和自然对流)，同时采用Prandtl的混合长度理论和双方程K-ε湍流模型的计算结果作为比较。

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％。