二维对流—扩散方程的控制体有限元法数值模拟

推导了二维对流—扩散方程的控制体有限元公式，其主要特点是所得离散化方程适合于逐点迭代法及共轭梯度法进行求解，使得该方法更适合于求解复杂的几何域及节省更多的计算机内存。通过几个算例表明，该方法对于特别大的Ｐｅｃｌｅｔ数其精度也是很高的     

Modeling of ionospheric parameter variations in East Asia during the moderate geomagnetic disturbances

The results of modeling of ionospheric disturbances observed in the East Asian region during moderate storms are presented. The numerical model for ionosphere–plasmasphere coupling developed at the ISTP SB RAS is used to interpret the data of observations at ionospheric stations located in the longitudinal sector of 90–130°E at latitudes from auroral zone to equator. There is obtained a reasonable agreement between measurements and modeling results for winter and equinox. In the summer ionosphere, at the background of high ionization by the solar EUV radiation in the quiet geomagnetic period the meridional thermospheric wind strongly impacts the electron concentration in the middle and auroral ionosphere. The consistent calculations of the thermospheric wind permit to obtain the model results which are closer to summer observations. The actual information about the space-time variations of thermosphere and magnetosphere parameters should be taken into account during storms.     

Understanding Substorms in the Magnetotail: Early Development and Recent Progress

This is a concise review of physics of the substorm in the magnetotail. It consists of two parts. The first part summarizes historical developments in the early days of the space age (1960--1975) when the basic concepts such as magnetotail and reconnection were established and the leading model of the substorm was introduced. The second part is an overview of the research conducted in recent years (1995--2010) when very significant advances have been achieved in understanding the substorm physics by virtue of several major satellites missions that addressed the magnetotail physics intensively.      

仪器设备间距对空间实验室机柜内部流动和传热的影响分析

为充分利用机柜内有限空间并改善仪器设备的散热环境,建立了空间实验室机柜的模型,运用数值计算方法,对不同仪器设备间距下机柜内流场和温度场进行求解,研究了不同布局仪器层平均风速和仪器表面平均对流换热系数的变化规律。结果表明,合理地选择仪器设备间距可以有效地改善其表面的散热状况,为空间实验室机柜的热设计提供了依据。     

枝晶生长中的对流效应与形态选择——地基实验研究

通过在生长界面前区域创生液相流动,研究了在稀薄合金中对流对强制性枝晶生长的作用。本文首次报告了对流对强制性枝晶生长的影响。SCN—Acc.模型合金中的定量实验表明,枝晶生长的动力学和形态是温度梯度、生长速度和枝晶端前沿液体流动速度的函数。作为以地面为基础的实验研究,将有助于理解太空凝固试验的结果。     

Experiments on unsteady vortex flowfield of typical rotor airfoils under dynamic stall conditions

A new experiment for airfoil dynamic stall is conducted by employing the advanced particle image velocimetry(PIV) technology in an open-return wind tunnel. The aim of this experimental investigation is to demonstrate the influences of different motion parameters on the convection velocity, position and strength of leading edge vortex(LEV) of airfoil under different dynamic stall conditions. Two different typical rotor airfoils, OA209 and SC1095, are measured at different free stream velocities, oscillation frequencies, and angles of attack. It is demonstrated by the measured data that the airfoil with larger leading edge radius could notably decrease the strength of LEV. The angle of attack(Ao A) of airfoil can obviously influence the dynamic stall characteristics of airfoil,and the LEV would be effectively inhibited by decreasing the mean pitch angle. In addition, the convection velocity of LEV is estimated in this measurement, and the results demonstrate that the influence of airfoil shape on convection velocity of LEV is limited, but the convection velocity of LEV would be increased by enlarging the oscillation frequency. Meanwhile, the convection velocity of LEV is a time variant value, and this value would increase as the LEV convects to the trailing edge of airfoil.     

用湍流附面层方程计算喷管内的对流换热

在流场计算的基础上,运用Patankar-Spalding方法积分求解了湍流附面层控制方程组,从而得到了固体火箭发动机喷管内燃气与壁面之间的对流换热。其中在附面层靠近壁面的底层区使用了Gouette流分析,在壁面边界和自由流边界处引入了滑移值的概念,因此保证了计算结果的相对准确性。最后将本文的计算结果与巴兹公式的计算结果和实验结果进行了比较。     

长时间气动加热飞行器的隔热机理

主要论述长时间气动加热飞行器热防护系统隔热机理的新概念，提出传统的单相固体热传导由于其隔热机制的局限性，已不能解决新型高超声速式飞行器的隔热问题，代之以气-固的辐射-传导-对流复合传热机制。多相复合传热机理可解决长时间气动加热飞行器隔热的问题。     

Magnetospheric electric field variations caused by storm-time shock fronts

On January 20, 2005 there was an X 7.1 solar flare at 0636 UT with an accompanied halo coronal mass ejection (CME). The resultant interplanetary shock impacted earth ∼36 h later. Near earth, the Advanced Composition Explorer (ACE) spacecraft observed two impulses with a staircase structure in density and pressure. The estimated earth-arrival times of these impulses were 1713 UT and 1845 UT on January 21, 2005. Three MINIature Spectrometer (MINIS) balloons were aloft on January 21st; one in the northern polar stratosphere and two in the southern polar stratosphere. MeV relativistic electron precipitation (REP) observed by all three balloons is coincident (<3 min) with the impulse arrivals and magnetospheric compression observed by both GOES 10 and 12. Balloon electric field data from the southern hemisphere show no signs of the impulse electric field directly reaching the ionosphere. Enhancement of the balloon-observed convection electric field by as much as 40 mV/m in less than 20 min during this time period is consistent with typical substorm growth. Precipitation-induced ionospheric conductivity enhancements are suggested to be (a) the result of both shock arrival and substorm activity and (b) the cause of rapid (<6 min) decreases in the observed electric field (by as much as 40 mV/m). There is poor agreement between peak cross polar cap potential in the northern hemisphere calculated from Super Dual Auroral Radar Network (SuperDARN) echoes and horizontal electric field at the MINIS balloon locations in the southern hemisphere. Possible reasons for this poor agreement include (a) a true lack of north–south conjugacy between measurement sites, (b) an invalid comparison between global (SuperDARN radar) and local (MINIS balloon) measurements and/or (c) radar absorption resulting from precipitation-induced D-region ionosphere density enhancements.     

超临界压力下低温甲烷的湍流传热数值研究

通过系统的数值模拟计算,在准确确定甲烷的热力学和传输物性变化的情况下,详细分析了两种热流密度下超临界压力对低温甲烷的湍流传热过程的影响,揭示了对流换热Nusselt数的变化规律。计算结果表明:在超临界压力下,热力学和传输物性对湍流传热现象会造成很大的影响,尤其在甲烷的临界区域附近,由于物性的剧烈变化会导致传热过程的恶化现象;在高热流密度情况下(如7MW/m2),增大管内压力有利于提高对流换热强度;现有的常用变物性湍流传热公式不能适用于超临界压力下低温甲烷的对流换热计算。