烟威渔场盐度预报及分析     

郑东  张瑞安 《中国海洋大学学报(自然科学版)》1989,(Z1)

本文以我国北黄海的烟威渔场为研究对象,采用优选因子场预报模式,对盐度的时空变化进行预报试验。文中对所采用的统计预报方法,作了简要介绍。对影响本海区盐度变化的显著因子及预报结果作了初步分析。预报试验表明:预报的总体平均绝对误差为0.27‰,预报相对误差在18％左右,预报误差小于0.5‰的站数占总站数的85％,预报趋势与实测资料基本一致。  相似文献   

Elasto-Plastic Analysis of Tubular Joints of Offshore Platforms by Finite Element Method     

Chen Tieyun Zhu Zhenghong Professor  Dept. of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai Lecturer 《中国海洋工程》1991,(1)

The plastic node method is reformulated by the variational principle and is applied to elasto-plastic finite element analysis of tubular joints, eventually including the effect of internal and external gussets, stiffener rings, etc., if necessary. Four different joints are studied here in detail for the elasto-plastic behavior, the strain at the hot spot, the strain concentration factor around the intersection line, and the propagation of the plastic region with loading up to collapse in order to determine the ultimate strength, safety factor, and development of the plastic field. The present results are in good agreement with the experimental results.  相似文献   

黄、渤海无机氮的收支模式初探   总被引：8，自引：1，他引：8  

王保栋  单宝田  战闰  藏家业 《海洋科学》2002,26(2):33-36

根据黄、渤海无机氮的收支状况，首次提出了黄、渤海无机氮的稳态收支模式。模式研究结果表明，大气沉降、陆源输入和海底输入的无机氮通量分别占黄、渤海无机氮浮游植物总需求量的3%、4%和12%。无机氮的外部输入约占总需求量的1/5，其他部分则由水柱中的内部再循环（再生）供给。  相似文献   

青岛市大气污染时间序列分析预报方法研究   总被引：5，自引：0，他引：5  

黄磊  王赐震  王建华  于鹏 《中国海洋大学学报(自然科学版)》2001,31(1):14-20

根据青岛市大气污染监测资料 ,采用时间序列分析方法 ,建立多种预报模型 ,有原序列周期外延法、均生函数周期外延法、均生函数逐步回归法以及自回归预报法等 ,最后提出一种综合预报模型。连续预报试验表明 ,综合预报模型优于任何个别预报模型 ,有较好的预报能力。利用马尔可夫概型对污染状态 (轻、中、重 )进行了分级预报试验 ,也获得良好的效果。  相似文献   

三传感器波浪水槽二次反射主动吸收方法     

李炎保  张兴无 《海洋科学进展》2001,19(1):82-85

三传感器波浪水槽二次反射主动吸收方法是加拿大科学院水力中心最近开发的一种水槽反射波控制技术。该法在造波板前 1～ 2倍波长处布置 3个传感器 ,通过入反射波分离方法得到准确的入反射波参数 ,以此调整造波信号 ,有效地吸收由建筑物反射回到造波板的二次反射波。文中在分析波浪水槽二次反射吸收方法研究现状的基础上 ,介绍了加拿大水力中心对现有方法的改进及其效果  相似文献   

Computation of Viscous Uniform and Shear Flow over A Circular Cylinder by A Finite Element Method     

赵明  滕斌 《中国海洋工程》2004,18(2):267-280

The incompressible viscous uniform and shear flow past a circular cylinder is studied. The two-dimensional Navier-Stokes equations are solved by a finite element method. The governing equations are discretized by a weighted residual method in space. The stable three-step scheme is applied to the momentum equations in the time integration. The numerical model is firstly applied to the computation of the lid-driven cavity flow for its validation. The computed results agree well with the measured data and other numerical results. Then, it is used to simulate the viscous uniform and shear flow over a circular cylinder for Reynolds numbers from lO0 to lO00. The transient time interval before the vortex shedding occurs is shortened considerably by introduction of artificial perturbation. The computed Strouhal number, drag and lift coefficients agree well with the experimental data. The computation shows that the finite element model can be successfully applied to the viscous flow problem.  相似文献   

长江口深水航道数学模型信息系统研究   总被引：3，自引：0，他引：3  

童朝锋  林跃华等 《海洋工程》2003,21(1):101-104

利用GIS二次开发软件ArcView，完成数学模拟所需的计算网格生成及线边界法中地形数据提取的优化。集成ArcView、Visual Basic及长江口潮流数学模型，实现了数值模拟计算成果的三维可视化及实时互动的动态演示。所开发的长江口数学模型信息系统能根据整治工程需要，提交各类工程数据库。  相似文献   

桶形基础平台三维有限元稳定性分析     

钱荣  周锡礽  孙克俐  张伟 《海洋技术学报》2003,22(4):49-53

以我国第一座桶形基础采油平台工程实例为原型，采用三维有限元计算方法对桶形基础稳定性分析。平台在波浪、风等荷载作用下，其稳定性不仅与平台的整体结构有关，而且与桶形基础及其周围土体相互作用相关。在计算中，利用薄层摩擦单元模拟土与结构间的相互作用，取得了很好的效果。分析结果表明桶形基础采油平台在设计条件下运行是较为稳定的。  相似文献   

An Experimental Study of Several Special Issues Regarding the Ice Force on Conical Structures     

SHI  Qing-zeng 《中国海洋工程》2002,16(4):561-568

The effect of the cone spacing of a conieal structure on the ice force is studied by model experiments. The ice force reduction coefficient presented in this paper expresses the relationship between the ice force and the arrangement of cones. The experiments prove that the mode of the ice failure before the boundary of upward-downward bending cone (UDBC) is crushing. A conclusion can also be drawn from the experiments that the ice force on the boundary of UDBC is by far less than that on a vertical pile with the same diameter. Moreover, the ice force frequencies on upright and inve-rted cones are obtained under the field condition of the platform JZ20-2, respectively. The results show that the alterna-tion of the ice force on UDBC can hardly induce resonance of platform JZ20-2.  相似文献   

Barotropic Response of the Sea of Okhotsk to Wind Forcing     

Daisuke Simizu  Kay I. Ohshima 《Journal of Oceanography》2002,58(6):851-860

We have examined wind-induced circulation in the Sea of Okhotsk using a barotropic model that contains realistic topography with a resolution of 9.25 km. The monthly wind stress field calculated from daily European Centre for Medium-Range Weather Forecasting (ECMWF) Re-Analysis data is used as the forcing, and the integration is carried out for 20 days until the circulation attains an almost steady state. In the case of November (a representative for the winter season from October to March), southward currents of velocity 0.1–0.3 m s⁻¹ occur along the bottom contours off the east of Sakhalin Island. The currents are mostly confined to the shelf (shallower than 200 m) and extend as far south as the Hokkaido coast. In the July case (a representative for the summer season from April to September), significant currents do not occur, even in the shallow shelves. The simulated southward current over the east Sakhalin shelf appears to correspond to the near-shore branch of the East Sakhalin Current (ESC), which was observed with the surface drifters. These seasonal variations simulated in our experiments are consistent with the observations of the ESC. Dynamically, the simulated ESC is interpreted as the arrested topographic wave (ATW), which is the coastally trapped flow driven by steady alongshore wind stress. The volume transport of the simulated ESC over the shelf reaches about 1.0 Sv (1 Sv = 10⁶ m³s⁻¹) in the winter season, which is determined by the integrated onshore Ekman transport in the direction from which shelf waves propagate. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献