Using data assimilation in laboratory experiments of geophysical flows

Data assimilation is used in numerical simulations of laboratory experiments in a stratified, rotating fluid. The experiments are performed on the large Coriolis turntable (Grenoble, France), which achieves a high degree of similarity with the ocean, and the simulations are performed with a two-layer shallow water model, using the SEEK method for data assimilation. Since the flow is measured with a high level of precision and resolution, a detailed analysis of a forecasting system is feasible. The procedure is tested for the baroclinic instability of a two-layer vortex. It is shown that the method of data assimilation properly captures the details of the initial flow perturbation. Then it is shown by sensitivity studies that an error of the model, attributed to small non-hydrostatic effects, can be distinguished from the error growth associated with the intrinsic instability of the system. Finally, it is experimentally demonstrated that the velocity field in the lower layer can be well controlled by data assimilation limited to the top layer.     

公路路基黄土湿陷性的室内实验研究

本文总结了目前关于湿陷性黄土湿陷机理的诸观点,对典型的湿陷性黄土地区的公路路基黄土进行了大量野外取样并进行了室内湿陷性试验,通过对试验结果的回归分析揭示了湿陷性与含水量、孔隙比、塑性指数的定量关系;并通过对切取的sem电镜照片进行分析,从微观角度对黄土微观结构特征与湿陷性之间的关系进行了有益的探讨。     

纤维沥青碎石封层配合比设计研究

通过分析提出适用于纤维沥青碎石封层材料的性能技术指标,并通过室内清扫试验,得出纤维沥青碎石封层的最佳配合比,即碎石用量为8m3/1000m2,乳化沥青用量为2.0kg/m2,纤维用量为60g/m2。在该配合比下,脱石率最小。     

两组耦合节理工况下隧道变形的数值研究

文章以玉山县高竹山隧道的围岩节理特征为基础,采用离散元软件UDEC建立二维计算模型,通过计算不同工况下的拱顶塌落高度值,研究了两组节理耦合工况下节理倾角、间距对隧道变形的影响。研究结果表明,随节理倾角的增大,塌落高度先增大(0°~30°时)后减小(30°~45°时)最后再增大(45°~90°时),且节理倾角为60°时塌落高度计算值与普氏理论值最为接近;当节理间距在0.2~1.0 m范围内时,随节理间距的增大塌落高度呈非线性减小;当间距接近1.0 m时,塌落高度降幅不明显;当间距不大于0.2 m时,计算值与普氏理论值最为接近。     

Residual stresses at a longitudinal stiffener — Web frame intersection and their effects on crack growth

Stress coining at geometrical discontinuities may introduce compressive residual stresses which will lower the propagation of surface cracks and thus increase the fatigue life. In a non-linear finite element analysis, the residual stresses after welding of a transverse web-frame to a ship hull plating is first estimated. Stress coining of one corner of a longitudinal cut-out in a transverse web-frame is then simulated in detail. The calculated residual compressive tangential stresses in the corner of the cut-out is seen to lower the propagation of edge cracks. Experiments performed on web-frames taken from a shipyard after manufacturing show indeed that large tensile residual stresses exist in the web-frame after welding. Stress coining is therefore believed to have a beneficial effect on the fatigue life.     

耐大气腐蚀钢09CuPCrNi板材机械性能的试验研究

本文对耐大气腐蚀钢09CuPCrNi板材的机械性能进行了试验研究,测定了其弹性模量E值,屈服极限σ_5、强度极限σ_b、延伸率δ和断面收缩率,分析了拉伸图的特点,确定了拉伸变形的硬化指数n值和板材的塑性应变比r值,并与A_3钢板材性能做了比较     

重庆门坎滩水电站泄流能力及消能结构试验研究

针对门坎滩水电站设计方案的泄流能力和消能效果等方面进行了模型试验,结果表明原设计方案存在溢流坝泄流过于集中以及消能效果差、容易形成坝下冲刷等问题。通过采用宽尾墩结构和修改消力池及闸孔边墩布置方式对原方案进行优化设计,其模型试验结果分析表明,优化方案泄洪能力、消能效果均满足工程要求。     

浅埋隧道塌方冒顶处理方法

结合某隧道浅埋段塌方事故,分析了隧道塌方的原因,介绍了隧道塌方冒顶的处理方法、施工要点。研究结果可为类似隧道塌方治理提供借鉴。     

阜新至朝阳高速公路湿陷性黄土地基处理研究

根据阜新至朝阳高速公路湿陷性黄土路段黄土的各项指标,归纳总结朝阳地区的湿陷性黄土特点,并根据其特点提出对湿陷性黄土地基处理方案。     

开放式物理实验教学的探索与实践

介绍了湖北汽车工业学院在物理实验教学内容、教学方式、教学手段等方面进行的探索与实践,总结了开放式物理实验教学所取得的成效和存在的问题。