Rayleigh Bénard(RB) convective system is simulated numerically using Direct Simulation Monte Carlo(DSMC) method which origins from micro-molecular dynamics. On the basis of DSMC simulation results,the critical Rayleigh number is obtained,which is consistent with the linear stability theory.

Results show that the convergence of low-level moisture flux, which occurs about 2~3 hours before the strong convective systems, is triggered and very strong.

In terms of 1979~1994 NCEP/NCAR re analyses and OLR data,the variation characteristics of tropical convective activities are investigated and the relationships between the interannual variation of summer OLR and East Asian summer monsoon(EASM) are discussed.

采用 1 979～ 1 994年 NCEP/NCAR再分析风场资料和 OL R资料 ,研究了热带对流的变化特征 ,讨论了热带对流年际变化与东亚夏季风的关联。

the long axis in positive value area of 500 hPa helicity is consistent with the causing severe convective warm area′s weak shear and moving towards of radar band echo;

The effects of absorption coefficient, refractive index, heat conductivity, convective heat-transfer coefficient and radiative properties of the surf ace on the temperature field are discussed too.

WT5”BZ]An heating effects analysis of laser unstable cavity CaF 2 window for convective cooling system is proposed. The influence upon temperature increment and temperature gradient of such different laser power is describe. The finit differential method is used to calculate the results .

用有限差分法计算了强迫对流冷却下非稳腔激光器 Ca F2 输出窗口在不同换热系数、不同激光功率和不同窗口厚度下的温升分布 ,温升随时间的变化及温度梯度沿激光输出方向的分布 ,分析了各个参数对激光器窗口温升的影响。

The distribution of temperature increment of CaF 2 output window is calculated, which used in 500kW DF laser cavity under convective cooling system. Effects of window's stress and beam's phase caused by plane window and spherical window are studied.

计算了对流冷却下 50 0 k W DF激光器 Ca F2 输出窗口的温升 ,得到了平板形和球壳形输出窗口的应力分布和光束的位相分布 ;

Radiative heat transfer in solids and convective heat transfer between the gas and the solid is especially studied.

Methods and algorithms of numerical simulation for three-dimensional thermal-convective motions of the inhomogeneous high-viscosity incompressible fluid in the direct and inverse time are described.

It is shown that, for univalent cations in the regime of convective diffusion, the coefficient of electrolyte rejection by the membrane correlates with the adsorption potential of cations (counterions) at the pore surface of a selective layer.

The gel-layer accumulates considerable surface and bulk charges and is characterized by the high hydraulic resistance hindering the convective ion transport.

It is shown that the effective mechanism of the saturation of nanocrystalline materials with impurities is their convective transfer by moving macrodislocations-linear defects of the regular packing of nanograins.

This is a brief report of a preliminary survey of certain rain-bearing systems over China in later spring and summer. In the first part, a general description of the methods of analysis used in this survey is given. As the temperature and wind fields are weak, and the precipitation is heavy, smaller intervals for the isotherms and contours in the constant pressure surface and pseudo-equivalent potential instead of potential temperature in the cross section analysis are used.In the second part, there are descriptions...

This is a brief report of a preliminary survey of certain rain-bearing systems over China in later spring and summer. In the first part, a general description of the methods of analysis used in this survey is given. As the temperature and wind fields are weak, and the precipitation is heavy, smaller intervals for the isotherms and contours in the constant pressure surface and pseudo-equivalent potential instead of potential temperature in the cross section analysis are used.In the second part, there are descriptions of the structure and development of five frequently observed rain-bearing systems i.e. cold front, blocking high and cold vortex, monsoon heat low, warm front and typhoon.The last part consists of discussions of some points of view in synoptic meteorology in China. It is stated that the monsoon precipitation is various in intensity and duration according the large-scale flow patterns. The difference of moisture content in the middle troposphere as a criterion for the identification of equatorial or tropical maritime air mass is proved to be missleading. It is shown that the upper air moist content is high only within the raining region near the polar or equatorial front. To the south of the equatorial front within the so-called equatorial air mass, the moist content in the middle troposphere is as low as within the tropical maritime air mass. It is the convergence and lifting of the tropical air mass which releases the convective instability and induces the surface moist air rising to the middle troposphere. The phenomenon of the forward-inclination of the so-called North-West Trough based on the time cross-section of wind is proved to be a mistake by combining two systems into one trough. The terminology of shear line, and the correct application of synoptic models in weather analysis and forecas-ting are also discussed.

In this paper, the drag effects of the precipitation particles on the air current in convective cloud are investigated, by applying the theory of motion of sand particles. It is found that: 1) the downward velocity of air thus produced is reasonable; 2) the precipitation has the character of a shower.

The structure of the solar convection zone was calculated by E.Vitense with the mixing length theory of turbulence.A fundamental formula in her calculations is the formula for the energy flux of turbulent convection [eq.(2.1)],or W.Schmidt's formula [eq.(2.1)].This formula should be modified by the following two corrections: (1)According to the argument of S.A.Zhevakin,the specific heat at constant pressure c_p in this formula should be replaced by (1/2)C=(1/2)(C_p—A_p),where A_p is the work required for the...

The structure of the solar convection zone was calculated by E.Vitense with the mixing length theory of turbulence.A fundamental formula in her calculations is the formula for the energy flux of turbulent convection [eq.(2.1)],or W.Schmidt's formula [eq.(2.1)].This formula should be modified by the following two corrections: (1)According to the argument of S.A.Zhevakin,the specific heat at constant pressure c_p in this formula should be replaced by (1/2)C=(1/2)(C_p—A_p),where A_p is the work required for the compression of one gram of medium when cooled for one degree at constant pressure.In this paper are derived the formulas of the factor C,for the hydrogen ionization zone [eq.(2.20)] and for the single ionization zone of helium [eq.(2.29)]in the envelope of a star.Eq.(2.32)is the formula for C in the critical double ionization zone of helium. (2)According to the investigation of E.J.Opik,in order to take account of the lateral exchange of heat between the turbulent elements,W.Schmidt's formula (2.1) should be multiplied by the factor f/B=0.188. The finally corrected formula is eq.(2.33).The ratio of the convective energy flux computed by eq.(2.33)to that computed by the original eq.(2.1)is 0.094C/c_p≈0.094/γ, since C is approximately equal to the specific heat at constant volume c_v and γ=c_p/c_v. This ratio is 0.0564 for ideal monatomic gas since γ=5/3 and is 0.0705 for fully ionized gas since γ=4/3.Obviously the convective energy flux computed by the original eq.(2.1) is overestimated by a factor 14—18. On the basis of the corrected formula (2.33),or(2.34),we derived anew in §4 some formulas for the calculation Of the solar convection zone as used by E.Vitense. It is obvious that E.Vitense's method and all the formulas in §§2,3 and 4 may be applied not only to the sun but also to other stars.The application to the sun is made in §5.The results are as follows: Fig.1 shows the variations of the gas pressure P_g as function of the geometrical depth t in the solar convection zone.The solid curve(——)corresponds to the model in which the mixing length l of the turbulent element is equal to H,the equivalent height of the atmosphere.The dashed curve(……)is for the model with l=2H.The thick- ness of the solar convection zone with l=H is found to be 3700km and the correspon- ding value of 65000kin found by E.Vitense with the original eq.(2.1)is 17.6 times overestimated.The thickness of the solar convection zone with l=2H is 8790km and the corresponding value of 160,000km found by E.Vitense is overestimated by a fac- tor 18.2. Fig.2 shows the temperature T as function of the gas pressure P_g.The solid curve stands for l=H and the dashed curve for l=2H as in other figures. In Fig.3 is shown T4 as function of the mean optical depth .The dashed line with dots (—·—·—) is for the model in radiative equilibrium. Fig.4 is the entropy diagram for the layers in the solar atmosphere.The left-hand solid curve shows the outermost layer in radiative equilibrium, then begins the convection zone in two models with l=H (——) and l=2H (……),and the right-hand falling parts of the curves correspond to the inner radiative layer. Fig.5 shows the ratio of πF_c to πF as function of P_g,where πF_c is the convective energy flux and πF is the total energy flux,i.e.,πF_c plus the radiative energy flux πF_rad. Therefore,it may be concluded that the thickness of the solar convection zone is some thousand kilometers in order of magnitude.

本文对经日瓦金改正过的对流能通量公式做了进一步的修改,并根据改正后的公式,重推了费坦瑟计算太阳对流层时所用的一些公式.然后计算了太阳对流层.得到的结果是:对于混合长 l 等于大气等值高度 H 的模型,对流层厚度是3700公里;对于 l =2H 的模型,对流层厚度是8790公里.