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1.
采用数值模拟和水力学模型,对沾化电厂扩建后徒骇河供水能力进行了定量计算.通过分析取水前后典型站位及河道沿程水位、流量的变化,对影响取水的因素进行了初步探讨,对增大取水量的工程措施提出了建议。  相似文献   

2.
钱塘江河口的风暴潮预报工作可归结为澉浦或乍浦两个单站的预报,这使得经验预报成为可能。利用一种动力线性模型将动力学的线性问题转化为统计学的线性回归模型,通过合理选取预报量及预报因子,并采用正交筛选技术确定每个预报因子所对应的系数,建立经验预报方程。后报结果表明该方法可取得较好的效果。  相似文献   

3.
Process-based modeling of morphodynamics of a tidal inlet system   总被引:1,自引:0,他引:1  
The morphodynamic evolution of an idealized inlet system is investigated using a 2-D depthaveraged process-based model,incorporating the hydrodynamic equations,Englund-Hansen’s sediment transport formula and the mass conservation equation.The model has a fixed geometry,impermeable boundaries and uniform sediment grain size,and driven by shore-parallel tidal elevations.The results show that the model reproduces major elements of the inlet system,i.e.,flood and ebb tidal deltas,inlet channel.Equilibrium is reached after several years when the residual transport gradually decreases and eventually diminishes.At equilibrium,the flow field characteristics and morphological patterns agree with the schematized models proposed by O’Brien (1969) and Hayes (1980).The modeled minimum cross-sectional entrance area of the tidal inlet system is comparable with that calculated with the statistical P-A relationship for tidal inlets along the East China Sea coast.The morphological evolution of the inlet system is controlled by a negative feedback between hydrodynamics,sediment transport and bathymetric changes.The evolution rates decrease exponentially with time,i.e.,the system develops rapidly at an early stage while it slows down at later stages.Temporal changes in hydrodynamics occur in the system;for example,the flood velocity decreases while its duration increases,which weakens the flood domination patterns.The formation of the multi-channel system in the tidal basin can be divided into two stages;at the first stage the flood delta is formed and the water depth is reduced,and at the second stage the flood is dissected by a number of tidal channels in which the water depth increases in response to tidal scour.  相似文献   

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   

5.
2014年底,在广西防城港核电厂一期工程1号机组热试期间,核电厂所在的冷源水取水海域钦州湾暴发了球形棕囊藻赤潮,赤潮严重时出现了冷却水系统堵塞现象,严重威胁到核电的安全。本次由藻类引发的威胁核电冷源安全的事件在国内尚属首例,以往人们更多关注核电的温排水对附近海域生物的影响,而反过来,生物对核电正常运行的潜在影响相比之下缺少研究。在此背景下,本文通过研究历史调查资料,对潜在影响防城港核电冷源系统的藻类及其暴发特点进行初步分析,以大规模暴发时易成囊、成团、成簇以堵塞核电冷源入水作为筛选标准,筛选出球形棕囊藻、束毛藻、夜光藻和浒苔几种潜在威胁种,进一步对潜在威胁种的预警监测和防控方法进行初步介绍,以达到早期预防、保障核电冷源系统安全用水的目的,并为其他核电厂提供参考。  相似文献   

6.
A study of the East Frisian Islands has shown that the plan form of these islands can be explained by processes of inlet sediment bypassing. This island chain is located on a high wave energy, high tide range shoreline where the average deep-water significant wave height exceeds 1.0 m and the spring tidal range varies from 2.7 m at Juist to 2.9 m at Wangerooge. An abundant sediment supply and a strong eastward component of wave power (4.4 × 103 W m−1) have caused a persistent eastward growth of the barrier islands. The eastward extension of the barriers has been accommodated more by inlet narrowing, than by inlet migration.

It is estimated from morphological evidence that a minimum of 2.7 × 105 m3 of sand is delivered to the inlets each year via the easterly longshore transport system. Much of this sand ultimately bypasses the inlets in the form of large, migrating swash bars. The location where the swash bars attach to the beach is controlled by the amount of overlap of the ebb-tidal delta along the downdrift inlet shoreline. The configuration of the ebbtidal delta, in turn, is a function of inlet size and position of the main ebb channel. The swash bar welding process has caused preferential beach nourishment and historical shoreline progradation. Along the East Frisian Islands this process has produced barrier islands with humpbacked, bulbous updrift and bulbous downdrift shapes. The model of barrier island development presented in this paper not only explains well the configuration of the German barriers but also the morphology of barriers along many other mixed energy coasts.  相似文献   


7.
In order to investigate the sediment dynamic behavior of the Yuehu, a small inlet system characterized by abundant sediment supply and rapid sediment infilling, measurements and sampling were undertaken to obtain data sets of tidal water levels, current velocities, suspended sediment concentrations, grain size parameters, deposition rates and organic carbon contents. Sediment budget and the time–velocity asymmetry patterns of the inlet system were analyzed. The results show that the deposition rates are relatively high within the tidal basin. The total sediment flux cannot be balanced by the input from the open sea, the aerosol and biological production; rather, the material from land (which has been intensified by agricultural activities over the past several decades) represents a major component for the balance. Thus, the denudation rate must be reduced to protect the Yuehu as a natural reserve. Furthermore, it is found from the present study that the Yuehu inlet system exhibits all of the four time–velocity asymmetry patterns with varied frequencies of occurrence, compared with the two asymmetry patterns identified for larger inlet systems; such phenomena are partly due to the adjustment of entrance channel geometry. This behavior may be representative of the small tidal inlets at their late stage of morphological evolution and, therefore, may be utilized to prolong the lifespan of small inlet systems.  相似文献   

8.
福建沿海海域波浪能资源分析与评价   总被引:2,自引:0,他引:2  
张军  许金电  郭小钢 《台湾海峡》2012,31(1):130-135
采用波浪模拟的方法,较准确计算得出福建沿海海域波浪能资源分布状况,并给出相应的分析和综合评价.主要结论如下:(1)福建沿海海域波浪能平均密度为2.6~7.3 kW/m,波浪能资源储量为2 210.45 MW,在我国沿海海域仅次于台湾和广东,是波浪能开发利用可以优先考虑的海区之一.(2)福建沿海海域波浪能资源储量的70%分布于平潭岛以北海域,其值达1 512.49 MW.其中,尤以北礵地区值最大,为378.80 MW.(3)以年平均波高为指标,福建沿海海域中东山区段为三类区,其他区段均为一类区和二类区,具有良好的开发前景.(4)福建沿海海域波浪能具有波功率密度低、资源分布广泛且不均匀、波功率密度随季节变化、能量具有多向性等分布特点.(5)基于福建波浪能的开发与利用现状,建议应优先着眼于解决边远海岛等特殊场所的用电问题.  相似文献   

9.
Invasions of non-indigenous species into coastal habitats have been a frequent phenomenon in the last decades, sometimes with significant impact on the receiving ecosystem. However, the understanding of the entire process and especially the relative importance of larval supply and local recruitment remains unclear. In this study, we simulate the invasion of a benthic invertebrate into a previously uncolonised habitat over several years and validate the results with field data. Therefore, we present field data from a monitoring programme revealing the rapid invasion of the oyster Crassostrea gigas into the East Frisian Wadden Sea, North Sea, between 2003 and 2005. The applied model combines a simple, spatially-explicit population dynamics model for the adult stage with a particle tracking model for the larval stage of the life cycle. Simulation results are able to reproduce the large-scale pattern of the field data and indicate a domination of larval supply on the population dynamics in the early stage of the invasion. Though monitoring and simulations suggest a single larval source outside the study area in the west, the population dynamics in the eastern part is only explainable with an additional source within the study area attributed to an unintentional input of juveniles by mussel fishery. High sensitivities to uncertain parameters result in distinct deviations between monitoring and simulations at particular sites. Especially the impact of site-specific variations of the post-settlement mortality underlines the variability of local recruitment conditions and indicates the need for spatially resolved information for exact predictions.  相似文献   

10.
The first Chinese experimental wave power plant, i. e., the shoremountcd experimental wave power plant at the Pearl River Estuary was successful in trial power generation on February 15, 1990. The plant is on the south shore of the Dawanshan Island in the Pearl River Estuary, facing the vast waving South China Sea. With a designed wave condition of H1/10= 1.5 m and T= 6.5 s, the planned installed capacity is 8 kW comprising the first unit of 3 kW brushless clawpole generator which delivers 110 V DC current and the second unit of 5 kW brushless single phase synchro AC generator which delivers 220 V AC current. At present, the first unit has been put into trial operation.  相似文献   

11.
近岸海域水母暴发可导致滨海火/核电厂取水口堵塞,对电厂安全运行造成潜在威胁。寻找水母源地及其迁移路径是水母治理的基础。本文基于拉格朗日质点追踪方法(LTRANS)建立反向追踪模型,并结合水母生态学特性对2015年6—9月聚集在红沿河电厂海域的大型水母进行溯源,获得水母源地及迁移路径,可以为螅状体栖息地寻找和水母拦截打捞提供依据,对近岸海域水母灾害防治具有重要指导意义。溯源结果表明:(1)红沿河电厂及其邻近海域的水母可能来自多个不同源区,辽东湾西部、北部及电厂南北两侧等海域的水母均有可能迁移至电厂附近;(2)受水温和环流影响,6—9月期间到达电厂附近的水母主要源区及迁移路径不同,早期出现在电厂海域的水母很可能是局地产生的,而7—9月持续的高风险水母灾害则主要取决于渤海不同源区水母的物理聚集;(3)根据水母的主要迁移路径,建议在电厂取水口约15km的海域设置一条封闭监测断面,对水母进行实时监测;在距离取水口约30km的外侧海域设置一条调查断面,于7月初至8月中旬,每5天进行一次定点拖网调查。此外,在距离电厂取水口15—20km的西南方向上,对水母进行拦截打捞可大大降低水母入侵风险。  相似文献   

12.
粤西水东潮汐通道流速不对称性及流速模拟分析   总被引:1,自引:0,他引:1  
彭炳健 《海洋科学》1987,11(6):17-22
本文分析了广东西部的水东泻湖-潮汐通道不同地段流速的分布持性。指出通道涨落潮流速不对称主要是由于潮水位不对称引起,通道潮流流速过程一方面决定于潮水位的涨落变率,另一方面与泻湖纳潮水域的地形及通道咽喉断面面积随水位变化的特性有关。  相似文献   

13.
The supply of particulate organic carbon (POC) via freshwater influx, and its exchange with the open sea, were estimated for a fjord-like coastal inlet (Killary Harbour, Ireland) during 1981. Biological production and destruction of organic matter within the inlet were also studied. POC levels in rivers feeding the system were correlated with rainfall. C : N ratios suggested an increased proportion of POC of terrestrial origin at stations influenced by freshwater inflow, and throughout the fjord in the non-productive season.A tentative annual carbon budget is presented.  相似文献   

14.
Eelgrass (Zostera marina L.) shoot density, seed-bearing shoot abundance, shoot length, and standing stock biomass were monitored during summer months from 1985 to 2000 at three locations in eastern Long Island Sound (LIS) near Millstone Power Station (MPS), Waterford, Connecticut, USA. Short-term declines in eelgrass abundance were directly associated with fouling and overgrowth of eelgrass on two occasions; once by blue mussels (Mytilus edulis) and once by a bloom of green algae (Cladophora spp.). Analysis of long-term trends indicated some degree of decline in most of the parameters examined at all three areas monitored. The spatial relationship of the long-term eelgrass declines suggests primary causal factors other than the power plant discharge or regional climate change. Two populations to the east of MPS and near the fringes of the thermal plume (<1.5 km from the MPS discharge to LIS) exhibited only slight declines over the 16-y study period and thermal input from MPS to these sites was minimal (<1 °C above ambient conditions). By comparison, heavy eelgrass losses were documented in the Niantic River, located >2 km from the power plant thermal plume. Die-offs of entire individual eelgrass study beds in the Niantic River were observed on five separate occasions during the study with no sign of recovery. While the causes were not determined, anthropogenic influences such as nutrient loading from surface run-off and groundwater sources may have contributed to observed declines. The Niantic River has a more restricted tidal inlet and is closer to sources of nutrient enrichment than Jordan Cove. Historically, eelgrass has ranged to far western reaches of LIS, but over the last century has become restricted to the easternmost third of the Connecticut coastline due to nutrient loading and eutrophication of the western portions. This study suggests that the west-to-east declining trend in eelgrass distribution in LIS may be further progressing.  相似文献   

15.
中国对虾(Penaeus chinensis)消化系统发生的研究   总被引:2,自引:2,他引:2  
本文对中国对虾消化道和中肠腺的发生进行了研究。完整的中肠管形成于N3期,它是由幼虫腹面的内胚层板向背中线上卷合拢而形成。在Z1期消化道完全贯通。至M1期,胃分化为贲门胃和幽门胃两部分,中肠前盲囊和中肠后盲囊也在此期出现,同时胃磨的雏形发生,但完整的胃磨形成于P期。另外,中肠腺始于N4-5期中肠前端突出的两对中肠腺盲囊。第一对中肠腺盲囊于M3期退化消失,而第二对中肠腺盲囊则发育为成体的中肠腺。中肠腺小管由4种不同类型的细胞(胚性细胞、吸收细胞、纤维细胞和泡状细胞)所组成  相似文献   

16.
为研究潮汐变化对连云港田湾核电站邻近海域温排水时空分布与变化规律的影响,利用Landsat-8热红外数据,构建基于劈窗算法的温度反演模型,结合潮汐数据分析田湾核电站邻近海域的温排水分布规律。得出结论:基于Landsat-8数据的劈窗算法温度反演模型应用在田湾核电站邻近海域温排水的监测效果较好;潮汐运动直接影响田湾核电站温排水的时空分布与扩散方向,并呈现一定的规律性。本文的研究方法为核电站温排水常规性监测提供了一定的技术参考。  相似文献   

17.
The population dynamics of the seagrass Cymodocea nodosa was investigated in three meadows differently affected by the artificial relocation of an inlet in the western sector of the Ria Formosa lagoon, southern Portugal. One meadow was subjected to increasing currents that caused erosion, another one was subjected to an initial episode of burial and a third meadow was undisturbed by the inlet opening. The hydrodynamic/sedimentary condition of meadows was assessed through comparative sediment analysis between the meadow and the adjacent unvegetated area.  相似文献   

18.
Sediment transport near the Tauranga entrance to Tauranga Harbour   总被引:2,自引:2,他引:0  
Abstract

Sediment transport at the Tauranga Entrance was studied in relation to tidal currents and waves. Bedforms resulting from tidal flow were investigated with scuba divers and echo‐soundings. The alignment and scale of bedforms indicated the direction and approximate rate of sediment transport. Sediment transport was measured directly using sediment traps, and results were compared with rates calculated by another method. Maximum sediment transport rates of 20 000–30 000 g.m?1 per half tidal cycle occur near the inlet gorge, but rates vary considerably in time and space, depending mainly upon power of tidal currents. A model of sediment transport for this inlet has been evolved based on tidal flow streamlines, bedform features, and the measured and calculated rates of sediment transport.  相似文献   

19.
谈浅海油田固定平台应急电站设计   总被引:2,自引:0,他引:2  
结合埕岛中心二号平台的设计实践,对浅海油田固定平台应急发电机组的选型、布置、辅助系统配置、供电范围等内容进行探讨  相似文献   

20.
This paper presents the test of a ship model for the design of a backward-bent duct oscillating water column type wave energy conversion system, to supply electric power for a light ship. This system suggests a new way to produce electric power automatically for large light ships.  相似文献   

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