基于FLUENT的海洋内孤立波数值水槽模拟

基于FLUENT商业软件及其二次开发功能,在标准κ-ε湍流模型下,采用VOF方法追踪两层流体内界面,通过给定入口速度和水位的设置造波边界法,建立了可有效模拟弱非线性内孤立渡的分层流数值水槽,并与仿物理的双板造波方法进行了比较.采用设置边界法所造的波形与理论值符合较好,这为数值分析内孤立渡与海洋结构物相互作用问题提供了一条更加有效的途径.     

大连港外海域船舶尾迹光学特征研究

通过大连港外海上实验测量船舶含气泡尾迹表观光学特征(如离水辐亮度、遥感反射率),分析了尾迹气泡对极度混浊的Ⅱ类水体海水表观光学特征的影响.实验结果证明:无论在可见光还是近红外波段,尾迹气泡都增强了海水表观光学量,如"耘海"船尾迹遥感反射率在可见光波段相对背景海水提高了50%,在近红外波段相对提高了159%.数据分析结果表明在此种水体中,气泡使得尾迹海水水色变黄,而不是在Ⅰ类水体中使水色变绿.随着观测点在尾迹中的位置靠近目标船,气泡数密度不断增加,遥感反射率也随之增强.     

绿洲城市化与生态环境互动作用关系研究进展

绿洲城市化与生态环境互动作用关系研究经历了萌芽、发展和多元化研究三个阶段。近年 来, 国内外学者继承了绿洲城市化与自然环境变迁关系的历史学分析, 多角度探讨了绿洲古城国 产生、繁荣和衰落过程中的自然因素和人为因素作用; 十分重视水资源约束下的流域绿洲城市化 研究, 基本确立水资源约束和上、中、下游协调发展为研究切入点; 非常注重绿洲城市化与生态环 境相互作用机理探究, 从中、长时间尺度分析了绿洲城市化与生态环境的耦合关系及其阶段性特 征; 广泛采用空间技术、复杂系统分析和数学分析等定量方法评估了城市化与生态环境的响应过 程; 普遍关注绿洲城市化对生态环境正负效应的辨析; 逐步加强对可持续绿洲城市化模式和对策 的探索, 并总结了绿洲城市化与生态环境协调发展的经验与教训。从研究趋势来看, 今后在研究 的可控性与对实践的指导性、多学科交叉研究和系统动态性研究等方面将得到加强。     

5月南极涛动对青藏高原西部夏季气温影响的诊断分析

青藏高原是全球气候变暖最敏感的地区之一,是北半球夏季最大的热源,其气候响应受到广泛关注。然而,有关南极涛动与青藏高原夏季气温的关系和机理知之甚少。为了研究南极涛动与青藏高原夏季气温的关系,基于1979—2020年英国东安哥拉大学气候研究中心（CRU）的逐月气温、美国国家海洋和大气管理局（NOAA）的逐月海表面温度和大气环流再分析数据以及南极涛动指数等数据,采用相关、回归、合成分析等方法进行研究。结果表明,北半球夏季青藏高原西部气温与5月南极涛动存在显著负相关,即当5月南极涛动异常偏弱时,夏季青藏高原西部气温异常偏高。其影响过程为,南极涛动为正位相时,在南印度洋中高纬地区出现“负-正-负”的经向“三极子”海温模态,该模态可持续到夏季,在印度洋形成异常的纬向-垂直环流,相应在热带西印度洋和东印度洋-海洋性大陆之间的降水异常导致热带正“偶极子”降水模态,通过该降水模态在青藏高原西部引起异常反气旋环流和下沉运动,有利于高原西部气温偏高。研究结果显示,海洋的热惯性在“延长”南极涛动影响过程中起着重要的桥梁作用,可为青藏高原夏季气温预测提供科学依据。     

皖西贵池、宿松地区中下三叠统沉积环境及层序分析

摘要：皖西中、下三叠统为一套碳酸盐岩沉积。从下往上,其沉积环境经历了从盆地－开阔陆棚－开阔台地－局限台地－潮上蒸发台地这样一个海水逐渐变浅、盐度不断增高的环境演化序列．据露头剖面分析,这套碳酸盐岩地层可分成３个层序。层序均由低水位、海进和高水位体系域组成,特征明显。据其岩性特征及准层序的叠置方式,识别出了追赶碳酸盐体系（ｃａｔｃｈｕｐｃａｒｂｏｎａｔｅｓｙｓｔｅｍ）和并进碳酸盐体系（ｋｅｅｐｕｐｃａｒｂｏｎａｔｅｓｙｓｔｅｍ）。     

A statistical analysis applied to the Rf/φ method

A statistical analysis for the R_f/φ method is developed in the paper. The technique provides estimates of R_s, R_i and θ according to R_f and φ. Moreover, we can restore the pattern of initial orientations of marker objects by means of their frequency histogram, provided the strain is homogeneous. It is unnecessary to postulate random initial orientations if the principal directions of strain ellipsoid are known.     

Strength behavior of slip-zone soils of landslide subject to the change of water content

Landslides are the major natural hazards in many countries all over the world and are usually caused by heavy rainfall, water level change of reservoir, excavation, earthquake, etc. Whether the landslide occurs or not in rainfall season, the strength variation of slip-zone soils of landslide is regarded as the vital control factor. Thus, strength behavior for slip-zone soils of landslide subject to the change of water content is required to be evaluated in a potential landslide area. In this paper, the shear strength of typical slip-zone soil, six groups of 25 specimens of remolded clay samples from Daxishan reservoir landslide, was systemically investigated using the improved direct shear test apparatus in order to fully understand its physical and mechanical properties, and also the shear and failure behavior. Furthermore, the fitting equations for expressing the relationship between the shear strength (effective cohesion and internal friction angle) and vertical loadings, initial water contents of slip-zone clay were established based on the experimental results. In particular, a series of shear stress–shear strain curves under various vertical loadings and different water contents were observed. The results show that a “softening” stress–strain behavior is achieved for unsaturated slip-zone soil, while a “hardening” curve is found for saturated slip-zone soil.     

New data on the Albian-Cenomanian radiolarians from the Karai Formation (South India)

Radiolarians from the lower part of the Karai Formation (upper Albian-middle Cenomanian) are studied in detail for the first time. Among over 50 radiolarian species identified in the formation, there are Acaeniotyle amplissima (Foreman), Savaryella novalensis (Squinabol), S. quadra (Foreman), Vitorfus campbelli Pessagno, Archaeodictyomitra montisserei (Squinabol), Holocryptocanium barbui Dumitrica, Pseudoeucyrtis sp. cf. Ps. spinosa (Squinabol), Stichomitra communis Squinabol, Tubilustrionella transmontanum (O’Dogherty), and others. The discovered radiolarians are divided into the Halesium triacanthum-Orbiculiforma nevadaenis (late Albian-early Cenomanian), Crucella latum-Cryptamphorella micropora (late Albian?-early Cenomanian), and Becus sp. B-Godia concava (terminal Albian-middle Cenomanian) assemblages. In general, the Albian-Cenomanian radiolarians of South India are comparatively less diverse than the concurrent assemblages of the Mediterranean region and California. In taxonomic composition and morphological peculiarities, they are comparable with the Aptian-Albian radiolarians of Western Australia (Ellis, 1993). Consequently it can be postulated that sea basins of South India were situated during the Albian-Cenomanian in the temperate latitudes of the Southern Hemisphere.     

流土和管涌破坏机理研究

首先针对渗流破坏的机理进行研究,区别在堤防工程中常用的流土和管涌的概念,从现有的大量土的渗流破坏的实验资料,结合理论分析,从微观的角度去阐述渗流破坏的形成机理,提出了在级配连续性土和级配不连续性土中进行管涌型土和流土型土判别的标准.然后从定量的角度去推导出各种渗流破坏类型的判别公式以及临界抗渗坡降计算公式.