共轭梯度法在三维复杂流动数值分析中的应用

将多块网格技术运用于三维T型管复杂流场的网格生成，利用不完全乔列斯基预处理共轭梯度，双共轭梯度方法求解N－S方程的离散方程。计算表明上述方法有良好的收敛特性，适合于诸如T型管等复杂流动的分析。     

基于变量分离的修正有限元数值计算

采用有限元方法直接求解粘性不可压缩流动N—S耦合方程，本文从离散化的动量方程和连续方程出发，得到了替代连续方程的压力简化统一方程，将各个求解变量分离开来，建立起直接从方程中求解压力场的有限元数值计算方法，有效地消除了压力场的伪震荡。通过对层流和紊流典型算例的分析比较，证明了本文方法是令人满意的。     

企业经营风险预警指标体系设计与预警系统模型设计

随着我国企业经营环境的显著改变，市场化程度的持续提高，对风险管理的需求和意义越来越高。本文立足于对中国石油天然气股份有限公司华北分公司的分析，归纳出营销类企业经营风险的指标体系，并在此基础上对该企业的经营风险预警体系和模型作了比较深刻的探讨。     

Modeling of single film bubble and numerical study of the plateau structure in foam system

The single-film bubble has a special geometry with a certain amount of gas shrouded by a thin layer of liquid film under the surface tension force both on the inside and outside surfaces of the bubble. Based on the mesh-less moving particle semi-implicit(MPS) method, a single-film double-gas-liquid-interface surface tension(SDST) model is established for the single-film bubble,which characteristically has totally two gas-liquid interfaces on both sides of the film. Within this framework, the conventional surface free energy surface tension model is improved by using a higher order potential energy equation between particles, and the modification results in higher accuracy and better symmetry properties. The complex interface movement in the oscillation process of the single-film bubble is numerically captured, as well as typical flow phenomena and deformation characteristics of the liquid film.In addition, the basic behaviors of the coalescence and connection process between two and even three single-film bubbles are studied, and the cases with bubbles of different sizes are also included. Furthermore, the classic plateau structure in the foam system is reproduced and numerically proved to be in the steady state for multi-bubble connections.     

企业经营风险预警指标体系设计与预警系统模型设计

随着我国企业经营环境的显著改变,市场化程度的持续提高,对风险管理的需求和意义越来越高.本文立足于对中国石油天然气股份有限公司华北分公司的分析,归纳出营销类企业经营风险的指标体系,并在此基础上对该企业的经营风险预警体系和模型作了比较深刻的探讨.