东海秋季典型站位沉降颗粒物通量   总被引：6，自引：0，他引：6  

张岩松  章飞军  郭学武  张曼平 《海洋与湖沼》2006,37(1):28-34

2002年9月在东海的长江口、中陆架区和浙江近岸上升流区三个站位放置沉积物捕获器采集沉降颗粒物。在对颗粒有机碳(POC)、颗粒有机氮(PON)和总颗粒碳(PC)元素分析基础上,采用颗粒物通量模型对沉降通量进行了研究。镜检发现细小无机颗粒物和大颗粒聚合体是三个站位沉降颗粒物的主要形式。大颗粒聚合体有住囊类、粪球聚合体、硅藻聚合体和混杂聚合体四种类型。研究结果显示,东海中陆架区和浙江近岸上升流区沉降颗粒物中POC、PON和PC的百分含量均呈现随水深增加明显降低的趋势,但在长江口,这些成分的含量低且上下均匀。长江口观测到的是大风后的一个实例,存在强烈的再悬浮,各水层颗粒物沉降通量平均(±SE)高达(319.02±65.33)g/(m2.d),尽管如此,沉降颗粒物有机态C/N值却很高(18.0±0.9),明显受陆源颗粒物的影响。POC净沉降通量在浙江近岸上升流区为961mg/(m2.d)(水深55m),在东海中陆架区为123mg/(m2.d)(水深88m),可见浙江近岸上升流区是POC向海底转移的重要区域之一,其垂直转移能力明显高于东海中陆架区。在上升流区域和中陆架区,POC的输出比率大约分别为48%—77%和15%—21%。浙江近岸上升流区和东海中陆架区底层颗粒物再悬浮比率分别为66.50%和88.52%。研究显示,浙江近岸上升流区的水体底层颗粒物受底部平流的影响比东海中陆架区相对较强。  相似文献   

天然感潮河道水流紊动特性分析   总被引：5，自引：0，他引：5  

卢金友徐海涛  姚仕明 《海洋工程》2005,23(3):70-77

采用多谱勒三相流速仪，在长江口徐六泾水文观测断面分别进行了涨潮、落潮时中泓与近岸垂线的流速观测，根据这些观测资料，对天然感潮河段潮流紊动的周期、频率、概率密度函数等进行了定量的数学描述，并对时均流速、紊动强度、雷诺应力等沿垂线分布进行了分析计算。  相似文献   

Estimation of Uplift Capacity of Rapidly Loaded Plate Anchors in Soft Clay     

S. P. Singh  D. P. Tripathy  S. V. Ramaswamy 《Marine Georesources & Geotechnology》2007,25(3):237-249

Plate anchors are extensively used in civil engineering constructions as they provide an economical alternative to gravity and other embedded anchors. The rate of loading is one of the important factors that affects the magnitude of soil resistance as well as soil suction force. This article outlines the effect of pullout rate on uplift behavior of plate anchors (70 mm diameter) buried in soft saturated clay by varying the pullout rate from 1.4 mm/min to 21.0 mm/min. The variation of breakout force and suction force with embedment depth and rate of pull are presented. A correlation between the rate of increase of undrained strength of clay and anchor capacity with rate of strain has been established. Finally an empirical equation has been proposed that includes the rate of pull in the estimation of breakout capacity of anchors.  相似文献   

河口海岸三维水流数值模型中几种垂向坐标模式研究述评     

陶建峰  张长宽 《海洋工程》2007,25(1):133-142

回顾了近年来国内外河口、近岸海域三维斜压水流数值模式研究的进展,着重讨论了不同垂向坐标下三维水流模式的发展状况以及存在的问题。地形拟合坐标(σ坐标)模式可以很好地拟合床面地形和自由面,已在物理海洋学中被广泛使用。但在地形变化剧烈,尤其在密度层结效应明显的海域,σ坐标模式中的水平压强梯度力误差会引起伪密度流。寻求高精度的数值模式以及更加有效的拟合坐标变换将是值得努力的方向。  相似文献   

现场海域水平扩散系数的探讨　Ⅱ．黄河三角洲埕北海域的计算     

匡国瑞  陈伯海  徐天真  钱成春  俞光耀 《中国海洋大学学报(自然科学版)》1995,(3)

根据Ｔａｙｌｏｒ的湍流扩散理论和Ｈａｙ、Ｐａｓｑｕｉｌｌ提出的拉格朗日流和欧拉流的相关函数的相似性，用黄河三角洲埕北海域的实测资料，按四种不同方案计算出该海域的水平扩散系数和谱密度分布。指出：该海区潮流扩散系数主要受潮流的影响，其分布特征与潮流的分布基本一致，所求的水平扩散系数主要是由周期性的潮运动给予潮流扰动所致。方案４是通过富氏变换滤波消去了周期性潮流扰动，本方案计算的水平扩散系数是由周期为６ｈ以下的小尺度涡提供能量。  相似文献   

Calculation of transverse hydrodynamic coefficients using computational fluid dynamic approach   总被引：1，自引：0，他引：1  

Amit Tyagi  Debabrata Sen 《Ocean Engineering》2006,33(5-6):798-809

Computational Fluid Dynamic (CFD) based on Reynolds Averaged Navier–Stokes equation is used for determining the transverse hydrodynamic damping force and moment coefficients that are needed in the maneuverability study of marine vehicles. Computations are performed for two geometrical shapes representing typical AUVs presently in use. Results are compared with available data on similar geometries and from some of the available semi-empirical relations. It is found that the CFD predictions compares reasonable well with these results. In particular, the CFD predictions of forces and moments are found to be nonlinear with respect to the transverse velocity, and therefore both linear and nonlinear coefficients can be derived. A discussion on the sources of the component forces reveal that the total force and moment variations should in fact be nonlinear.  相似文献   

黄骅电厂取水河段取水特性的数模与物模研究     

童中山  应新亚  钱炳法 《海洋工程》1997,(4)

本文采用数值模拟与物模试验相结合的研究方法，详细地研究了黄骅电厂一、二、三期工程的取水特性。结果表明，现有河道只能满足电厂一期工程的取水需求；若将现有河道进行适当开挖，可以满足电厂三期取水需要。  相似文献   

Wave interaction with a submarine pipeline in clayey soil due to random waves     

A. Vijaya kumar  S. Neelamani 《Ocean Engineering》2005,32(13):1517-1538

The wave pressure and uplift force due to random waves on a submarine pipeline (resting on bed, partially buried and fully buried) in clayey soil are measured. The influence of various parameters viz., wave period, wave height, water depth, burial depth and consistency index of the soil on wave pressures around and uplift force on the submarine pipeline was investigated. The wave pressures were measured at three locations around the submarine pipeline (each at 120° to the adjacent one). It is found that the wave pressure and uplift force spectrum at high consistency index of the soil is smaller compared to that of low consistency index. Just burying the pipeline (e/D=1.0) in clayey soil reduces the uplift force to less than 60% of the force experienced by a pipeline resting on the seabed (e/D=0.0) for I_c=0.33.  相似文献   

潮汐调和分析的一种算法   总被引：1，自引：1，他引：1  

宋志尧  严以新  茅丽华 《海洋工程》1997,(3)

本文在常规潮汐调和分析方法的基础上，提出了一种由高低潮资料进行潮汐分析的算法。具体计算表明，该算法与现今通用的常规算法（即等间隔最小二乘法）相比，既可大大减少所需原始样本量，在相同记录长度内，是常规算法的三分之一还少，同时减少样本处理的前期工作量；又能保证潮位拟合的精度和预报的可信度，两者精度相当，结果一致。该算法原理简单、实用有效，对于局部样本缺损较易处理，具有实际应用价值。  相似文献   

夏季东海西部表层海水中的pCO₂及海-气界面通量   总被引：10，自引：0，他引：10  

谭燕  张龙军  王凡  胡敦欣 《海洋与湖沼》2004,35(3):239-245

根据2001年夏季长江口及东海西部海域表层海水pCO  相似文献