Numerical Investigation of Submarine Hydrodynamics and Flow Field in Steady Turn

This paper presents numerical simulations of viscous flow past a submarine model in steady turn by solving the Reynolds-Averaged Navier?Stokes Equations (RANSE) for incompressible, steady flows. The rotating coordinate system was adopted to deal with the rotation problem. The Coriolis force and centrifugal force due to the computation in a body-fixed rotating frame of reference were treated explicitly and added to momentum equations as source terms. Furthermore, velocities of entrances were coded to give the correct magnitude and direction needed. Two turbulence closure models (TCMs), the RNG model with wall functions and curvature correction and the Shear Stress Transport (SST) model without the use of wall functions, but with curvature correction and low-Re correction were introduced, respectively. Take DARPA SUBOFF model as the test case, a series of drift angle varying between 0° and 16° at a Reynolds number of 6.53×106 undergoing rotating arm test simulations were conducted. The computed forces and moment as a function of drift angle during the steady turn are mostly in close agreement with available experimental data. Though the difference between the pressure coefficients around the hull form was observed, they always show the same trend. It was demonstrated that using sufficiently fine grids and advanced turbulence models will lead to accurate prediction of the flow field as well as the forces and moments on the hull.     

基于恐龙足迹重建攀西地区白垩纪恐龙动物群

攀西地区没有白垩纪恐龙骨骼化石记录,对该区白垩纪恐龙动物群组合的认识尚属空白。1991年,攀西地区首次发现了恐龙足迹,此后陆续发现了8个足迹点。这些足迹点共发现9种不同的非鸟恐龙足迹(6种非鸟兽脚类、1种蜥脚类和2种鸟脚类足迹),以及翼龙和龟类足迹。共11种足迹形态类型由185道行迹(与孤立足迹)组成,可能代表着同等数量的造迹者。其中飞天山组的组合多样性最强,小坝组和雷打树组较弱。这个相对全面的足迹数据库,为该地区白垩纪四足类的古生态学普查提供了动物群的组成信息,这在该缺乏骨骼化石的地区显得尤为重要。     

Ultimate Bending Capacity of Strain Hardening Steel Pipes

Based on Hencky’s total strain theory of plasticity, ultimate bending capacity of steel pipes can be determined analytically assuming an elastic-linear strain hardening material, the simplified analytical solution is proposed as well. Good agreement is observed when ultimate bending capacities obtained from analytical solutions are compared with experimental results from full-size tests of steel pipes. Parametric study conducted as part of this paper indicates that the strain hardening effect has significant influence on the ultimate bending capacity of steel pipes. It is shown that pipe considering strain hardening yields higher bending capacity than that of pipe assumed as elastic-perfectly plastic material. Thus, the ignorance of strain hardening effect, as commonly assumed in current codes, may underestimate the ultimate bending capacity of steel pipes. The solutions proposed in this paper are applicable in the design of offshore/onshore steel pipes, supports of offshore platforms and other tubular structural steel members.     

SHRIMP Zircon U‐Pb Age of the Piqiang Layered Intrusion in the Tarim Large Igneous Province and Subducted Slab‐Plume Interaction in Its Petrogenesis

正Objective During the Permian,at least four mafic continental large igneous provinces(LIPs)were formed in eastern Asia,i.e.,the Siberian traps(~251 Ma),Emeishan LIP(~260 Ma),Tarim LIP(~290–270 Ma)and Panjal traps(~290 Ma)(Shellnutt et al.,2015).The Emeishan and Tarim LIPs in China are both known for the presence of several magmatic Fe-Ti-V oxide deposits hosted in layered maficultramafic intrusions.The origin of such magmatic Fe-Ti-     

Comparative Study of Hydrogen and Carbon Isotopic Composition of Gases Generated from the Pyrolysis of a Peat under Saltwater and Freshwater Conditions

To understand the influence of the diagenetic water medium on the isotopic compositions of thermogenic coalbed gas, both hydrous and anhydrous closed-system pyrolyses were performed at temperatures of 250°C to 650°C on an herbaceous marsh peat. Compared to the results of anhydrous pyrolysis, the hydrocarbon gases generated from hydrous pyrolyses have very different hydrogen isotopic compositions. However, the carbon isotopic compositions of the hydrocarbon gases became only slightly heavier in hydrous pyrolysis, compared to that from anhydrous pyrolysis. With the progress of thermal evolution from peat to a more advanced thermal maturity of vitrinite reflectance values (Ro) of 5.5% during the pyrolysis, the difference in the average δD value increased from 52‰ to 64‰ between the hydrous pyrolysis with saltwater and anhydrous pyrolysis and increased from 18‰ to 29‰ between the hydrous pyrolysis with freshwater and anhydrous pyrolysis, respectively. The difference in the average δ13C value was only 1‰–2‰ between the hydrous and anhydrous pyrolysis. The relationships between the δD values of the generated hydrocarbon gases and Ro values as well as among δD values of the hydrocarbon gas species are established. The close relationships among these parameters suggest that the water medium had a significant effect on the hydrogen isotopic composition and a minimal effect on the carbon isotopic composition of the hydrocarbon gases. The results of these pyrolyses may provide information for the understanding of the genesis of coalbed gas from herbaceous marsh material with the participation of different diagenetic water media.     

层状土毛细水上升过程中Lucas-Washburn模型评价及修正

受界面效应影响,毛细水在层状土中运移规律还难以用描述均质土中水分运移规律的Lucas-Washburn（LW）渗吸模型进行描述。基于此,本文设计了层状土室内模型试验,采用分布式的主动加热光纤法（简称AHFO）监测毛细水上升过程。根据AHFO测试结果,进一步对LW模型进行了修正,提出了适用于描述层状土中毛细水上升规律的ILW模型,并对ILW模型进行了试验验证。试验结果表明:（1）当毛细水湿润锋抵达“黏土（下部）-砂土（上部）”界面时,会产生“毛细屏障作用”,从而导致上部砂土中毛细水含水率急剧下降;（2）“毛细屏障作用”由砂土和黏土中的基质吸力不均衡造成,基质吸力大小由含水率决定;（3）当毛细水湿润锋抵达“砂土（下部）-黏土（上部）”界面时,在界面处出现“反毛细屏障作用”,从而导致上部黏土层中的含水率比相邻下部砂土层含水率更高;（4）虽然常见的LW模型可准确预测均质土中毛细水上升高度及速率,但受“毛细屏障作用”和“反毛细屏障作用”影响,LW模型在层状土中失效;（5）相比LW模型,ILW模型精度更高,能够更加准确地描述层状土中毛细水上升规律。     

基于LabView的松科2井项目管理系统

松科二井2013年正式启动,2018年5月完井,历时6年,最终井深7018 m。项目执行过程中,形成合同700多个、文件200多个、汇款流水1000多笔、报账流水1600多笔。针对松科二井合同、文件繁多,财务流程繁杂,涉及项目多的特点,基于LabVIEW平台设计了一套项目管理系统。该系统可全程记录松科二井上述合同、文件、汇款和报账信息,建立合同及对应批次汇款和报销的勾稽关系,具有模糊查询、修改、超链接等功能。     

大兴安岭十八站—韩家园地区中酸性侵入岩LA-ICP-MS锆石U-Pb年龄、地球化学特征及其地质意义

大兴安岭北部塔河县十八站—呼玛县韩家园地区发育早古生代中酸性侵入岩。文章选取二长闪长岩和二长花岗岩开展岩石年代学与地球化学研究。二长闪长岩LA-ICP-MS锆石U-Pb年龄为512.4±3.5 Ma,为早—中寒武世岩浆作用的产物。岩石地球化学分析表明,中酸性侵入岩归属于准铝质—弱过铝质(A/CNK=0.77~1.04)钙碱性—高钾钙碱性系列。岩石稀土总量∑REE=69.51×10~(-6)~275.83×10~(-6),轻重稀土分异明显(La/Yb)_N=9.11~26.64。在稀土元素配分图上,显示为LREE富集、HREE相对平缓的右倾型,Eu异常不显著(δEu=0.90~1.35)。微量元素组成具明显富集大离子亲石元素Ba、Sr,显著亏损高场强元素Nb、Ta、Ti的特征。结合区域资料和本文研究,初步分析认为早古生代侵入体形成于活动大陆边缘或岛弧环境,为前古亚洲洋闭合背景下萨拉伊尔造山作用的产物。     

广西桂林凉风洞秋冬季滴水和沉积物氧同位素对极端降水的记录研究

近年来,全球环境变化导致的极端气候事件的发生频率剧增,引起了国内外学者的广泛关注。由于器测记录时间较短,因此需要通过精确连续记录古气候变化的石笋来解译极端气候事件的规律。本文针对桂林凉风洞2015年9月至2016年1月的大气降水、洞穴滴水和现代沉积物的氧同位素组成进行了高分辨率的监测。监测结果揭示了由于秋冬水汽源的改变,导致桂林地区大气降水δD、δ~(18)O同位素值显示逐渐偏正的季节性变化,并且建立了该区域大气降水线为:δD=8.8δ~(18)O+16.38。由于大气降水作为凉风洞水源补给唯一来源,使得洞穴滴水的δ~(18)O继承大气降水的δ~(18)O所蕴含的环境信息,进而记录在洞穴现代沉积物中。但是受到洞穴顶部岩溶表层带的平滑或者均一化的作用,使得洞穴滴水的δ~(18)O同位素值要偏正于大气降水的δ~(18)O同位素值。在极端降水信号输入岩溶表层带后由于存在不同的水文地球化学过程,从而导致洞穴沉积物对其极端降水事件的响应时间存在不同,并且在δ~(18)O同位素值也存在明显差异。因此,系统监测洞穴滴水、沉积物δ~(18)O同位素对外界环境信息的响应过程,能为量化或精确解译石笋δ~(18)O同位素记录所指代的古气候环境信息提供基础。     

菲律宾迪纳加特岛30#矿权区红土型镍矿床地质特征及成矿作用探讨

30~#矿权区位于菲律宾迪纳加特岛北部,区内发育有红土型镍矿床。本次勘查圈定4处矿(化)体,其中以Ⅰ、Ⅱ、Ⅲ矿(化)体的矿化范围较大,厚度变化系数为45%~50%(相对稳定),经济价值较高。红土型镍矿体平面上呈地毯状展布于地表,厚度受地形控制,富镍矿体分布于矿权区东部的5、6、11、12小区;剖面上从地表向深部矿体为铁质红土层、松散红土层及高岭土化蛇纹石化橄榄岩层。30~#矿权区红土镍矿矿床的形成经历了从普通矿到富矿两个阶段,红土镍矿石属于酸性矿石。