海洋平台动力分析的一个简化方法

本文提供了一个分析结构——基础耦合响应的简化方法。用SAPV计算上部固端悬臂结构后,将它变换为一个随频率变化的等价刚性质量,使问题简化为位于柔性基础上的刚体振动问题。用本法计算了一个简化的平台模型的随机响应。

我国爆炸加工技术的发展概况

简要介绍了我国自1960年开始的爆炸加工理论、工艺及应用研究方面的进展。

气流激光的增益、强度和功率理论

在速率方程中唯象地引进粒子的热速度分布,求得气流激光的增益、强度和功率诸关系.均匀加宽为主时本文关系与文[1]的理论结果一致,流速为零时简化为非流动气体激光的熟知关系~[4]. 分析中考虑了镜子反射率变化、光腔上游气体激励度随时间而变化的影响.对连续和脉冲CO_2气动激光进行了具体计算.

Experiment on the thermocapillary convection of a mercury liquid bridge in a floating half zone

A liquid bridge of a floating half zone consisting of liquid mercury sealed in a glass tube with nitrogen atmosphere was used for the experiment of thermocapillary convection with a low Prandtl number liquid. A non-contacted diagnostic method was developed to monitor the surface flow and the surface oscillation. A growing surface film (or skin) is a crucial source to suppress thermocapillary convection, and is discussed in this paper. For the case of a mercury Liquid bridge, the critical Marangoni number was obtained as 900, and the oscillatory frequency was around 5 Hz.

Molecular dynamics studies on the local disordering of σ3 and σ11 grain boundaries in aluminium bicrystal

Molecular dynamics (MD) simulations using Morse interaction potential are performed in studies of [110] symmetrical tilt grain boundary (GB) structures with mis-orientation angles 50.5 degrees(Sigma 11), 129.5 degrees(Sigma 11), 70.5 degrees(Sigma 3) and 109.5 degrees(Sigma 3) at various tempratures. The GB structures are found to start local disordering at about 0.5T(m)(T-m is the melting point of aluminium) for 50.5 degrees(Sigma 11), 0.32T(m) for 129.5 degrees(Sigma 11) and 0.38T(m) for 70.5 degrees(Sigma 3), respectively. These results agree with conclusions deduced from the anelastic measurements. But, for twin-boundary structure 109.5 degrees(Sigma 3), this disordering has not been found even when temperature increases up to 0.9T(m).

On the interaction of water waves and seabed by the porous medium model

The interaction of water waves and seabed is studied by using Yamamoto's model, which takes into account the deformation of soil skeletal frame, compressibility of pore fluid flow as well as the Coulumb friction. When analyzing the propagation of three kinds of stress waves in seabed, a simplified dispersion relation and a specific damping formula are derived. The problem of seabed stability is further treated analytically based on the Mohr-Coulomb theory. The theory is finally applied to the coastal problems in the Lian-Yun Harbour and compared with observations and measurements in soil-wave tank with satisfactory results.

A perturbational h4 exponential finite-difference scheme for the convective diffusion equation

A perturbational h4 compact exponential finite difference scheme with diagonally dominant coefficient matrix and upwind effect is developed for the convective diffusion equation. Perturbations of second order are exerted on the convective coefficients and source term of an h2 exponential finite difference scheme proposed in this paper based on a transformation to eliminate the upwind effect of the convective diffusion equation. Four numerical examples including one- to three-dimensional model equations of fluid flow and a problem of natural convective heat transfer are given to illustrate the excellent behavior of the present exponential schemes, the h4 accuracy of the perturbational scheme is verified using double precision arithmetic.

关于中央分隔带护栏立柱基础的探讨

目前高速公路中央分隔带波形梁护栏立柱的实际设置中，普遍存在着由于分隔带地基强度低于压实路基，护栏立柱承载能力偏低，护栏的防护性能达不到设计要求的问题。本文对粘性土地基中立柱的受力情况进行了分析，并对地基为压实土与回填土两种情况进行了对比，给出了中央分隔带中立柱地基的加固方案。

一种新的二维平板分叉流槽的设计

目的 解决平行平板流槽每次实验只能观测壁面培养细胞受一种剪应力作用的问题。方法 作者在平行平板流槽的基础上，首次提出了一种改进后的流槽-二维平板分叉流槽。通过数值模拟，给出了流体作定常流动时，流速和壁面剪应力的分布。结果 结果发现，利用这种二维平板分流槽可以研究壁面培养的细胞在不同大小剪应力作用下的力学行为。结论 该研究结果为流槽的合理设计和使用，并分析剪应力空间分布对内皮细胞的影响有重要实际意义。

剪切水-气界面下湍流猝发特征的实验研究

利用氢气泡时间线-脉线组合示踪技术定量地考察剪切水-气界面下的湍流猝发现象,分析猝发事件的信号特征,重点探讨猝发与湍能产生之间的联系.在猝发过程中,水面近区的瞬时流速和Reynolds切应力出现较大幅度的脉动,它们在时间和空间垂直方向上表现出高度的相干性,这是猝发事件的一个显著特征.在猝发期,猝发事件涉及的空间区域内Reynolds切应力和湍流脉动强度明显比平均值和非猝发期的情况大.其结果表明:在所考察的实验条件下,猝发是剪切水-气界面附近湍流产生的主要过程.

火箭剩余推进剂排放过程的分析与模拟

为了减少空间碎片的产生，星箭分离后，需要在轨排放火箭末级贮箱内的剩余推进剂．分析表明，排放条件下的推进剂射流进入太空后，立即失稳破碎为大量液滴；液滴在高真空环境下扩散，它们的表面不断有气体分子蒸发，逐渐在箭体周围形成了一个由液滴和蒸气分子组成的羽流场．采取Lagrange方法追踪该流场中每个液滴的运动轨迹以及表面蒸发冷凝过程，利用直接模拟Monte Carlo方法计算蒸气分子的运动和碰撞，然后通过微观量的统计平均获得感兴趣的宏观流场、箭体表面的压力和剪应力分布等．为了检验稀薄蒸气算法、模型和程序，模拟了真空水射流周围水蒸气羽流场，获得的径向Pitot压力分布与Fuchs和Legge的实验数据的符合．在此基础上，分别模拟了CZ-4B火箭末级剩余燃料偏二甲肼在不同排放方式下的三维稀薄蒸气与液滴羽流场．计算表明：原排放方式的扰动力矩相当大，超出了火箭姿控范围，新排放方式的扰动力矩很小，处于火箭姿控范围之内．这些预测得到了飞行遥测数据的支持．

低渗透油藏渗吸法采油的数值模拟

针对渗吸法采油中的毛管力驱动项和流动系数的取值问题，根据地下流体渗流特征，建立了低渗透油藏渗吸法采油数学模型，给出了数值解法．定量分析了渗吸法采油的主要影响因素，通过实例验证，用该方法计算的各项动态指标与矿场实际值符合程度较高．结果表明：基质与裂缝渗透率之比小于O．Ol，油水黏度比小于15，毛管力较大的水湿油层比较适合于渗吸法采油，能够提高水驱采收率2％左右．

Assessment of bursting detection methods with LES database of turbulent channel flows

Validated by comparison with DNS, numerical database of turbulent channel flows is yielded by Large Eddy Simulation (LES). Three conventional techniques: uv quadrant 2, VITA and mu-level techniques for detecting turbulent bursts are applied to the identification of turbulent bursts. With a grouping parameter introduced by Bogard & Tiedemann (1986) or Luchik & Tiederman (1987), multiple ejections detected by these techniques which originate from a single burst can be grouped into a single-burst event. The results are compared with experimental results, showing that all techniques yield reasonable average burst period. However, uv quadrant 2 and mu-level are found to be superior to VITA in having large threshold-independent range.

郭永怀先生诞辰九十周年纪念文集

目录

K418合金和42CrMo钢激光焊焊缝的微观组织

采用透射电镜及附带能谱(TEM-EDS)对K418高温合金涡轮盘和42CrMo合金钢转轴激光焊焊缝的微观组织进行了分析.结果表明:焊缝主要由树枝状非平衡凝固的FeCrNiC(γ)固溶体组成,此外,还有少量细小、弥散的Ni_3Alγ'相、Laves颗粒和少量MC碳化物分布在树枝晶之间区域;根据热动力学原理对形成这一组织特征的原因进行了简要讨论.