人工岛对潮汐河口水动力特性的影响分析

以山东某具有代表性的在建人工岛为实例,采用数值模拟的方法,建立人工岛附近海域的水动力模型和波浪模型,对区域径流、风生流、潮流、波浪进行数值模拟,分析人工岛对河口、海岸水动力环境的影响,探究人工岛作用下河口、海岸水沙运动规律,为人工岛的规划和设计提供依据。     

钱塘江河口沙坎演变的数值模拟研究

运用Delft3D软件模拟钱塘江河口沙坎的形成演变过程,探讨钱塘江河口沙坎的演变机理.将钱塘江河口概化为喇叭形,假定底质泥沙粒径单一,不考虑波浪作用,在径流和潮汐的作用下,建立钱塘江河口沙坎演变的数值模拟,重现沙坎演变的过程.钱塘江河口沙坎的形成演变主要受水动力、泥沙输运、河床演变三者非线性相互作用的控制.流域来水与外海潮汐的相互作用为沙坎提供了水动力条件,外海巨量泥沙输入为沙坎形成提供了丰富的泥沙来源.     

河口最大浑浊带研究进展

河口作为一个流域和海洋之间巨大的"过滤器",最大混浊带在其中起到极其重要的作用。最大浑浊带对河口沉积过程和河口的生物地球化学过程均产生显著影响,由于其在河口航道维护、河口学理论和河口生物地球化学过程中的重要性,近几十年来引起了国内外多个学科领域学者的广泛关注,本文主要就河口最大混浊带在河口动力沉积方面,特别是形成机制方面及数值模拟的研究进行综述。     

近河口引水工程建设对河口盐水上溯的影响分析——以海南省海口市南渡江引水工程为例

近河口引水工程建设使得河口水动力情况发生改变,从而改变河口盐水入侵。以海南省海口市南渡江引水工程为例,运用数值模拟方法,分析工程建设对南渡江河口水动力和盐水入侵的影响。研究结果表明:南渡江引水工程建设后,南渡江入海水量减小,年内减幅枯水期比丰水期大;河口区余流、海甸溪和北干流盐通量也有所减小,枯水期减小幅度比丰水期大;逐月咸水界出现不同程度的上移,丰水期上移距离比枯水期稍远。     

伶仃洋河口环流特征及其动力机制分析

基于FVCOM模型,该文建立了珠江河口三维水动力数值模式,模式覆盖了上游三角洲河网区域、八大口门区域以及伶仃洋等近岸海域。该模式的水位、流速和流向验证结果表明模式能较为准确地反映伶仃洋的潮汐潮流变化过程。对珠江河口枯季水动力特性进行了数值模拟,并基于模拟结果分析了伶仃洋余流的时空变化特征及动力成因。结果表明,伶仃洋深槽中存在表层余流向海、底层余流向陆的河口环流特征,且河口环流特征随大小潮发生明显变化:小潮期间河口环流特征较为明显,小潮后的中潮期间最为显著,大潮时河口环流特征减弱,大潮后的中潮期间表底层余流几乎均为向海,河口环流特征趋于消失。这种纵向上的余流变化特征主要是与河口斜压作用有关。此外受东北风作用,伶仃洋横向上存在一个表层余流向西,底层余流向东的横向风生环流。     

江苏省入海河口治导线规划

近年来江苏沿海开发进程不断加快,部分滩涂选址不当,加剧了河口的淤积,导致河道排水能力下降。为此,迫切需要划定入海河口治导线,加强河口管理,保障河口防洪排涝安全。文章运用DEM微地形分析、多时相遥感影像解译以及近海河口水动力数值模拟等技术,统筹河口开发利用要求,形成入海河口治导线成果,明确河口管理范围。     

河口、海岸的水波数值模拟

综合分析了河口、海岸中水波的数值模拟内容,介绍了几种典型的水波数学模型、数值技术、软件系统及其在河口、海岸中水波的数值模拟的应用实例。     

中山河口近岸海域混合区敏感点访问几率研究

以黄海中山河口近岸海域水动力、污染物输移扩散规律及污染物排放量对附近海域影响为主要研究内容。建立二维水流、水质模型,利用有限体积法离散方程并对中山河口近岸海域的水动力状况及污染物输移扩散规律进行数值模拟;选用COD为主要的污染物指标,模拟计算污染物混合区,然后确定混合区内相对不利的3个敏感点,应用统计学原理,统计混合区近岸边缘污染物访问几率。     

基于Delft3D-flow模型的长江口盐度扩散规律模拟

为了研究长江口环流动力过程下的河口盐度扩散和分层混合机制,采用河口三维模型(Delft3D-flow)模拟了长江口盐度分层扩散规律和扩散系数变化对河口分层的影响。通过模拟实际水文情况下的长江口水动力过程,反映了该区域受到较强的径潮流动力作用后,对盐度在涨落潮周期内的垂向混合分层产生了重要影响,进一步验证了分层河口紊动扩散系数对盐度的水平扩散输移、垂向非稳定层化和混合的影响均较大。模拟结果较好地反映了河口在复杂水动力过程下盐度扩散和分层规律。     

珠江河口水动力一维、二维联解的有限元计算方法

该文应用有限元联解方法计算珠江河网与河口的整个水动力。仿照四点隐式差分法在每个一维单元内部形成独立的单元方程组,改进RMA有限元软件包实现河网一维数值模拟。借鉴弹性力学年中通过固结杆件与块体的连接结点实现两构件组合计算的思路,设计了珠江河网一维、河口二维水动力联解的有限元法,通过单元矩阵的构建、合并与叠加,形成整体方程组,实现整体求解的连接模式,有效地解决了不同形态流场的模拟问题。应用研究表明:该方法合理,计算结果较理想。     

长江口风暴潮流场计算

利用一、二维数学模型，并考虑长江口深水航道治理工程的进展情况，对长江口区风暴潮流场进行了数值模拟计算。计算结果表明，治理工程对风暴潮引起的增长影响不显著，风暴潮增水期间潮位升高，涨、落潮流速及长江口北槽的分流会增大。     

“烟花”台风影响下长江南通以下河段的增水分布特征

为探讨台风对河口区域的影响,构建了覆盖中国东南沿海大范围数学模型,对2106号台风“烟花”产生的风暴潮进行了模拟,与实测气象及水位数据对比表明该模型可靠、合理。基于此模型,研究了“烟花”台风在长江口地区风暴潮增水的时空分布特征。研究表明,“烟花”台风期间,长江口区域整体表现为增水状态,最大增水大于0.5 m区域北至连云港、南至台州。南通以下河段最大增水值分布较均匀,均在1.5 m左右;上游区域增水幅度随潮汐过程呈规律波动,增水在涨潮中间时刻达到最大,于落潮中间时刻降至最低,至下游区域,波动规律逐渐消失;0.5 m以上增水历时从上游至下游逐渐减小。     

Inundation analysis of the effectiveness of an estuarygate in Hori River

Storm surges and floods around bays in Japan frequently result in water disasters. Both dikes and estuary gates can be constructed in urban areas near bays as counter measures. Estuary gates at the mouth of a river are intended to protect the upstream areas from storm surges and tsunamis. The sewer systems in urban areas also decrease the inundation. In this study, a numerical simulation is carried out to examine the effectiveness of the estuary gate and performance of the sewer system. A synthetic analysis model of inundation phenomena is developed and applied to the behavior of water in the urban area near the Nagoya Port and the estuary region of the Hori River. The developed model consists of models for the sea, river, sewer, overland flood flow, and typhoon. The inundation analysis model is validated by a comparison of analytical and observed results. The features of the inundations in the urban area caused by various conditions are discussed.     

Inundation analysis of the effectiveness of an estuarygate in Hori River

Storm surges and floods around bays in Japan frequently result in water disasters. Both dikes and estuary gates can be constructed in urban areas near bays as counter measures. Estuary gates at the mouth of a river are intended to protect the upstream areas from storm surges and tsunamis. The sewer systems in urban areas also decrease the inundation. In this study, a numerical simulation is carried out to examine the effectiveness of the estuary gate and performance of the sewer system. A synthetic analysis model of inundation phenomena is developed and applied to the behavior of water in the urban area near the Nagoya Port and the estuary region of the Hori River. The developed model consists of models for the sea, river, sewer, overland flood flow, and typhoon. The inundation analysis model is validated by a comparison of analytical and observed results. The features of the inundations in the urban area caused by various conditions are discussed.     

Effects of cluster land reclamation projects on storm surge in Jiaojiang Estuary,China

Variations in coastline geometry caused by coastal engineering affect tides, storm surges, and storm tides. Three cluster land reclamation projects have been planned for construction in the Jiaojiang Estuary during the period from 2011 to 2023. They will cause significant changes in coastline geometry. In this study, a surge-tide coupled model was established based on a three-dimensional finite-volume coastal ocean model (FVCOM). A series of numerical experiments were carried out to investigate the effects of variations in coastline geometry on tides, storm surges, and storm tides. This model was calibrated using data observed at the Haimen and Ruian gauge stations and then used to reproduce the tides, storm surges, and storm tides in the Jiaojiang Estuary caused by Typhoon Winnie in 1997. Results show that the high tide level, peak storm surge, and high storm tide level at the Haimen Gauge Station increased along with the completion of reclamation projects, and the maximum increments caused by the third project were 0.13 m, 0.50 m, and 0.43 m, respectively. The envelopes with maximum storm tide levels of 7.0 m and 8.0 m inside the river mouth appeared to move seaward, with the latter shifting 1.8 km, 3.3 km, and 4.4 km due to the first project, second project, and third project, respectively. The results achieved in this study contribute to reducing the effects of, and preventing storm disasters after the land reclamation in the Jiaojiang Estuary.     

库区滑坡涌浪数值模拟方法研究进展

对近年来库区滑坡涌浪涉及的边坡失稳、滑动、涌浪产生和传播这4个阶段研究中采用的数值模拟方法的研究进展和发展趋势进行了综述,重点归纳总结了边坡滑动过程以及涌浪产生过程的数值模拟方法的研究成果,指出滑坡涌浪从库区边坡失稳到涌浪传播是一个完整连续的过程,今后需要在目前各个阶段独立研究的基础上融合固体力学和流体力学两类学科中的相关研究方法,建立库区滑坡涌浪全程数值模拟方法,实现滑坡涌浪的全过程模拟。     

河北沧州沿海风暴潮特征与防御措施

对黄骅港潮位资料进行了分析,阐述了该海区风暴潮特点及潮灾影响因素,并分析了灾情构成及海堤抗御风暴潮的效益,对防潮减灾措施进行了探讨。     

Hydrodynamic modelling of flow impact on structures under extreme flow conditions

Apart from the direct threat to human lives, the flood waves as a result of the rapid catchment response to intense rainfall, breaches of flood defences, tsunamis or storm surges may induce huge impact forces on structures, causing structural damage or even failures. Most existing design codes do not properly account for these impact forces due to the limited understanding of the underlying physical processes and the lack of reliable empirical formulae or numerical approaches to quantifying them. This paper presents laboratory experiments to better understand the interaction between the extreme flow hydrodynamics and the hydraulic structures and uses the measured data to validate a numerical model. The model solves the two-dimensional shallow water equations using a finite volume Godunov-type scheme for the reliable simulation of complex flow hydrodynamics. New model components are developed for estimating the hydrostatic and hydrodynamic pressure to quantify the flow impact on structures. The model is applied to reproduce two selected experiment tests with different settings and satisfactory numerical results are obtained, which confirms its predictive capability. The model will therefore provide a potential tool for wider and more flexible field-scale applications.     

渤海湾滨州岸段风暴潮经验预报模型

根据渤海湾滨州岸段实测潮水、气象、地理资料,对该段沿海风暴潮发生的原因及灾害进行了分析,在此基础上建立了简易的风暴潮经验统计预报模型,并成功预报该沿海发生的风暴潮,为渤海湾滨州岸段防灾、减灾提供科学依据。     

Spatio-temporal distribution characteristics and influencing mechanisms of storm surge in Guangdong. Hong Kong and Macao Greater Bay AreaEI北大核心CSCD

基于1970—2018年珠江口潮位站历史潮位资料，结合风暴潮数值模拟结果，统计分析了粤港澳大湾区风暴潮的时空分布特征并探讨了风暴潮增水影响机理。结果表明：在空间分布上，伶仃洋、狮子洋、前航道等区域出现较大增水的频率较高，与该区域特殊的地理位置及伶仃洋河口湾漏斗状形态产生的能量辐聚有关，增水极值与台风登陆地点和台风强度均有关系；风暴潮发生时间主要集中在7—9月，占全年总次数的74.4%；影响粤港澳大湾区的强台风以上级别的台风频次增加趋势明显，各站点历年最高潮位呈增加趋势，平均速率为0.02~0.03m/a；台风路径对风暴潮增水的空间分布有较大影响，当台风在大湾区西岸登陆，距离台风登陆点约2.5倍最大风速半径的位置可产生较大的增水值；最大增水随着台风中心压强的降低而升高，中心压强每下降10hPa，最大增水值上升0.4~1.1m；当台风移动速度接近8.3m/s，珠江口形成较为稳定的风暴潮水位梯度，产生较大的风暴潮增水。