Effects of tide-surge interaction and wave set-up/set-down on surge: case studies of tropical cyclones landing China's Zhe-Min coast

Storm surge along the China＇s Zhe-Min coast is addressed using the tightly coupled surge model ofADCIRC＋SWAN. In this study, we primarily focus on the effects of surge-tide interaction and waveset-up/set-down. And the influences of intensity and landing moment of tropical cyclone （TC） arealso presented. The results show that： water elevation without considering tide-surge interactiontends to be underestimated/overestimated when TC lands during astronomical low/high tide;tide-surge coupling effect is more pronounced north of TC track （more than 0.7 m in our cases）;irrelevant to TC＇s intensity, wave set-up south of TC track is negligible because the depth-relatedwave breaking doesn＇t occur in water body blown towards open seas.

Heterogeneous tide-surge interaction during co-occurrence of tropical and extratropical cyclones in the radial sand ridges of the southern Yellow Sea

The Radial Sand Ridges(RSRs)area in the southern Yellow Sea are subject to tropical and extratropical cyclone activities frequently,in which the special geometry feature and moving stationary tidal system result in complex storm-induced hydrodynamic processes,especially the tide-surge interactions.We studied a rare weather event influenced simultaneously by an extratropical cyclone EX1410 and Typhoon Vongfong as an example to investigate the characteristics of storm surges,wave-surge,and tide-surge interaction in the RSRs area,and applied a high-resolution integrally-coupled ADCIRC+SWAN model,in which the meteorological forcing inputs are simulated by the WRF-ARW model.The model is validated by records from 4 tide gauges and 2 wave buoys along the Yellow Sea coast.Results show that the tide-surge interactions are of considerable regional heterogeneousness.The surge curves at Lüsi(in south RSRs)and Jianggang(in middle RSRs)have abrupt falls near the time of low tide,where the peak occurrence time of interaction residuals tend to shift towards the mid-ebb period.Significant increase of bed shear stress in shallow waters was proved the dominant factor to affect the tide-surge interaction in broad tidal flats of the RSRs area.Differently,the interaction pattern in the Xiyang Trough(in north RSRs),showed a unique rising in mid-flood period due to the phase advances of real surge waves in relatively deep waters.Therefore,we suggested to the local flood risk management that the tide-surge interaction tends to alleviate the flooding risk in the RSRs area around the time of high tide,but aggravate the risk on the rising tide in the Xiyang Trough and on the falling tide in large-scale tidal flats of the southem RSRs area.

A NUMERICAL STUDY OF THE TIDE-SURGE INTERACTION IN THE EAST CHINA SEA AND THE SOUTH CHINA SEA

Nearshore sea levels in the East China Sea(ECS) and the South China Sea(SCS) during tropical cyclones-Typhoon 8007(Joe, 1980) and Typhoon 7209(Betty 1972) were simulated. The tide-surge interactions in the two regions are remarkable and locally produced. The corresponding nonlinear effects were derived from the different nonlinear terms. The contribution of the quadratic friction term is the most important, the shallow term comes second the convective term is the least; the phases of the interactions generated by the various nonlinear terms are asynchronous. Both the quadratic friction and the convective term can stimulate and aggravate the surge structure with more peaks. The bottom friction features have crucial influences on tides and surges, and the interaction is sensitive to the changes of tide and surge.

An Efficient Tide-Surge Interaction Model for the Coast of Bangladesh

The numerical method of lines(MOLs)in coordination with the classical fourth-order Runge Kutta(RK(4,4))method is used to solve shallow water equations(SWEs)for foreseeing water levels owing to the nonlinear interaction of tide and surge accompanying with a storm along the coast of Bangladesh.The SWEs are developed by extending the body forces with tide generating forces(TGFs).Spatial variables of the SWEs along with the boundary conditions are approximated by means of finite difference technique on an Arakawa C-grid to attain a system of ordinary differential equations(ODEs)of initial valued in time,which are being solved with the aid of the RK(4,4)method.Nested grid technique is adopted to solve coastal complexities closely with least computational cost.A stable tidal solution in the region of our choice is produced by applying the tidal forcing with the major tidal constituent M2(lunar semi-diurnal)along the southern open-sea boundary of the outer scheme.Numerical experimentations are carried out to simulate water levels generated by the cyclonic storm AILA along the coast of Bangladesh.The model simulated results are found to be in a reasonable agreement with the limited available reported data and observations.

INTERACTION BETWEEN WAVES AND TIDE-SURGE MOTION AND A JOINT WAVE-TIDE SURGE MODEL

This paper describes in detail the interaction between waves, tides and storm surges and covers theeffects of wave on tides and storm surges and the influence of tides plus storm surges on waves. Some pro-blems deserving attention and improvements are put forward. And finally a combined wave-tide-surge numerical model YE-JWTSM is presented,with all relevant interaction processes considered, includ-ing wave-dependent surface wind stress and bottom-stress as well as current-induced refrac-tion and frequency shift.

The effect of wave-induced radiation stress on storm surge during Typhoon Saomai(2006)

The effects of wave-induced radiation stress on storm surge were simulated during Typhoon Saomai using a wave-current coupled model based on ROMS （Regional Ocean Modeling System） ocean model and SWAN （Simulating Waves Nearshore） wave model. The results show that radiation stress can cause both set-up and set-down in the storm surge. Wave-induced set-up near the coast can be explained by decreasing significant wave heights as the waves propagate shoreward in an approximately uniform direction; wave-induced set-down far from the coast can be explained by the waves propagating in an approximately uniform direction with increasing significant wave heights. The shoreward radiation stress is the essential reason for the wave-induced set-up along the coast. The occurrence of set-down can be also explained by the divergence of the radiation stress. The maximum wave-induced set-up occurs on the right side of the Typhoon path, whereas the maximum wave induced set-down occurs on the left side.

Numerical study on effect of tidal phase on storm surge in the South Yellow Sea

Because of the special topography and large tidal range in the South Yellow Sea,the dynamic process of tide and storm surge is very complicated.The shallow water circulation model Advanced Circulation(ADCIRC)was used to simulate the storm surge process during typhoon Winnie,Prapiroon,and Damrey,which represents three types of tracks attacking the South Yellow Sea,which are,moving northward after landing,no landing but active in offshore areas,and landing straightly to the coastline.Numerical experiments were carried out to investigate the effects of tidal phase on the tide-surge interaction as well as storm surge.The results show that the peak surge caused by Winnie and Prapiroon occurs 2-5 h before the high tide and its occurring time relative to high tide has little change with tidal phase variations.On the contrary,under the action of Damrey,the occurring time of the peak surge relative to high tide varies with tidal phase.The variation of tide-surge interaction is about 0.06-0.37 m,and the amplitude variations of interaction are smooth when tidal phase changes for Typhoon Winnie and Prapiroon.While the interaction is about 0.07-0.69 m,and great differences exists among the stations for Typhoon Damrey.It can be concluded that the tide-surge interaction of the former is dominated by the tidal phase modulation,and the time of surge peak is insensitive to the tidal phase variation.While the interaction of the latter is dominated by storm surge modulation due to the water depth varying with tide,the time of surge peak is significantly affected by tidal phase.Therefore,influence of tidal phase on storm surge is related to typhoon tracks which may provide very useful information at the design stage of coastal protection systems.

Fully Nonlinear Time Domain Analysis for Hydrodynamic Performance of An Oscillating Wave Surge Converter

The hydrodynamic behaviour of an oscillating wave surge converter(OWSC) in large motion excited by nonlinear waves is investigated. The mechanism through which the wave energy is absorbed in the nonlinear system is analysed. The mathematical model used is based on the velocity potential theory together with the fully nonlinear boundary conditions on the moving body surface and deforming free surface. The problem is solved by the boundary element method. Numerical results are obtained to show how to adjust the mechanical properties of the OWSC to achieve the best efficiency in a given wave, together with the nonlinear effect of the wave height. Numerical results are also provided to show the behaviour of a given OWSC in waves of different frequencies and different heights.

Effects of hurricane forward speed and approach angle on storm surges: an idealized numerical experiment

The effects of hurricane forward speed(V)and approach angle(θ)on storm surge are important and a systematic investigation covering possible and continuous ranges of these parameters has not been done before.Here we present such a study with a numerical experiment using the Finite Volume Community Ocean Model(FVCOM).The hurricane track is simplified as a straight line,such that V andθfully define the motion of the hurricane.The maximum surge is contributed by both free waves and a forced storm surge wave moving with the hurricane.Among the free waves,Kelvin-type waves can only propagate in the down-coast direction.Simulations show that those waves can only have a significant positive storm surge when the hurricane velocity has a down-coast component.The optimal values of V andθthat maximize the storm surge in an idealized semi-circular ocean basin are functions of the bathymetry.For a constant bathymetry,the maximum surge occurs when the hurricane approaches the coast from the normal direction when the free wave generation is minimal;for a stepped bathymetry,the maximum surge occurs at a certain acute approach angle which maximizes the duration of persistent wind forcing;a step-like bathymetry with a sloped shelf is similar to the stepped bathymetry,with the added possibility of landfall resonance when the free and forced waves are moving at about the same velocity.For other cases,the storm surge is smaller,given other parameters(hurricane size,maximum wind speed,etc.)unchanged.

Wave-current interaction during Typhoon Nuri(2008)and Hagupit(2008):an application of the coupled ocean-wave modeling system in the northern South China Sea

The northern South China Sea(SCS) is frequently affected by typhoons. During severe storm events, wave-current interactions produce storm surges causing enormous damage in the path of the typhoon. To evaluate the influence of wave-current interactions on storm surge, we used a coupled ocean-atmospherewave-sediment transport(COAWST) modeling system with radiation-stress and vortex-force formulations to simulate two typically intense tropical storms that invaded the SCS, namely Typhoons Nuri(2008) and Hagupit(2008), and compared results with observations from the Hong Kong Observatory. Both radiationstress and vortex-force formulations significantly improved the accuracy of the simulation. Depending on which typhoon and the topography encountered, the influence of surface waves on the oceanic circulation showed different characteristics, including the differences of range and intensity of storm surge between vortex-force and radiation-stress experiments. During typhoon landing, strong sea-surface elevation in concert with wave set-up/set-down caused the adjustment of the momentum balance. In the direction perpendicular to the current, but especially in the cross-shore direction, the pressure gradient and wave effects on the current dominated the momentum balance.

Will oscillating wave surge converters survive tsunamis?

With an increasing emphasis on renewable energy resources, wave power technology is becoming one of the realistic solutions. However, the 2011 tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable in the open ocean but as the wave approaches the shore its energy is compressed, creating large destructive waves. The question posed here is whether an oscillating wave surge converter （OWSC） could withstand the force of an incoming tsunami. Several tools are used to provide an answer： an analytical 3D model developed within the framework of linear theory, a numerical model based on the non-linear shallow water equations and empirical formulas. Numerical results show that run-up and draw-down can be amplified under some circumstances, leading to an OWSC lying on dry ground t

Effects of tide-surge interactions on storm surges along the coast of the Bohai Sea, Yellow Sea, and East China Sea

A two-dimensional coupled tide-surge model was used to investigate the effects of tide-surge interactions on storm surges along the coast of the Bohai Sea, Yellow Sea, and East China Sea. In order to estimate the impacts of tide-surge interactions on storm surge elevations, Typhoon 7203 was assumed to arrive at 12 different times, with all other conditions remaining constant. This allowed simulation of tide and total water levels for 12 separate cases. Numerical simulation results for Yingkou, Huludao, Shijiusuo, and Lianyungang tidal stations were analyzed. Model results showed wide variations in storm surge elevations across the 12 cases. The largest difference between 12 extreme storm surge elevation values was of up to 58 cm and occurred at Yingkou tidal station. The results indicate that the effects of tide-surge interactions on storm surge elevations are very significant. It is therefore essential that these are taken into account when predicting storm surge elevations.

高坝大库滑坡涌浪对水工建筑物作用力研究综述

库坝区滑坡体入水激起的涌浪灾害链对水工建筑物构成安全威胁.本文对高坝大库滑坡涌浪对水工建筑物作用力相关研究成果和发展趋势进行综述,概述了国内外典型滑坡涌浪实例及其危害,基于规范推荐公式、物理模型试验和数值模拟方法对库区滑坡涌浪对大坝坝体冲击压力相关研究成果进行总结归纳,提出应关注涌浪二次冲击阶段对水工结构的影响、开展坝前涌浪回落对坝面构筑物结构产生拖曳力的相关研究.总结了涌浪对通航建筑物作用力的相关研究,分析表明,现有关于涌浪对通航建筑物作用力的研究并不完全适用于库区滑坡涌浪对高坝水工结构作用,需开展专题研究.在现状分析的基础上,对高坝大库滑坡涌·浪对水工建筑结构作用的进一步研究提出了建议与展望.

某桥梁锚碇区地表水-地下水交互作用下涌水量预测

工程建设中地下水与地表水的交互作用对建设区域水位变化、水流情况、水质问题等水文地质条件与工程设施的建设及运行具有重要影响。本文以某桥梁锚碇区基础工程为研究对象,综合分析区域工程地质条件,基于水位监测结果揭示地表水与地下水交互作用,综合抽水试验确定的渗透系数,对基坑不同季节涌水量进行预测。结果显示:基坑平均总涌水量Q在高枯水位达到248643.03 m^(3)/d,常态枯水水位在232355.12 m^(3)/d,低位枯水为221667.78 m^(3)/d。雨季低位洪水基坑总涌水量为277195.44 m^(3)/d,常态洪水为287451.68 m^(3)/d,高位洪水位为368451.04 m^(3)/d;在地表水与地下水交互作用下,该锚碇基坑涌水量极大,实施单纯的降水方案不但风险大且无法保证长时间维持,难以保障锚碇基础安全施工,需根据实际工程情况设计合理施工方案。本研究对类似工程涌水量预测具有一定参考意义。

风暴潮与天文潮非线性相互作用的理论分析

对一维狭长半封闭水域中的风暴潮与天文潮非线性相互作用问题进行了研究,并用摄动方法求出了纯风暴潮增水ζS、天文潮增水ζT及风暴潮与天文潮非线性相互作用形成的增水ζST的一阶近似解析表达式.通过三者表达式的分析,直观地讨论了浅水效应、非线性效应在风暴潮与天文潮非线性相互作用中的影响.结果表明,浅水效应对增水水位起主要作用,非线性效应对增水的作用取决于波幅与水深比值的量阶.

上海沿岸天文潮与风暴潮非线性相互作用的数值研究

运用二维非线性风暴潮、天文潮和联合水位模型对8次不同路径的热带气旋引起的上海地区天文潮与风暴潮的非线性相互作用进行了数值研究，讨论了由天文潮与风暴潮非线性相互作用引起的增水特征，分析了控制方程中各非线性项对天文潮与风暴潮非线性相互作用引起的水位变化的贡献。研究表明，考虑天文潮与风暴潮的非线性相互作用后，使风暴潮和水位的数值模拟结果得到了改善，非线性底摩擦在控制天文潮和风暴潮非线性相互作用中起着重要的作用，而非线性浅水项和动量对流输送对两潮的非线性相互作用也不可忽视。

输流管道非线性流固耦合振动的数学建模

本文利用 Hamilton变分原理和变形体内流体运动的 N- S方程建立了描述输流管道非线性流固耦合振动的控制方程 ,形成描述弱约束管道 ,输送可压缩流体、具有定常或非定常流动状态系统的非线性 4-方程模型。模型全面考虑了管道中流体的喘振特性 ,并包括了各种耦合机理。通过对现有代表性模型的讨论和比较可以看出 ,本文导出的全耦合 4-方程模型是目前较完善的描述输流管道流固耦合运动的非线性动力模型。

长江河口动力与风暴潮相互作用研究

长江口是我国最大的河口,风暴潮是本地区最严重的自然灾害之一.本文分析了本地区风暴潮发生的特点,建立了中尺度气象模式驱动下长江感潮河段河口海岸风暴潮预报数学模型,分析了风暴潮与长江河口动力的相互作用.结果表明,长江河口地区受风暴潮作用特别明显,河口风暴潮最大增水在江阴与徐六泾之间,其位置受上游径流和河口潮汐的影响而摆动;并指出了长江口天文潮、风暴潮与长江洪水作用的一般规律,预测了长江口风暴潮作用下的洪水位.

输流管道流固耦合振动研究进展

管道在众多的工业领域中具有十分广泛的应用 ,发挥着极其重要的作用。但管道在工作过程中由于流体流动状态的变化引起喘振 ,诱发出流体、管道间的耦合振动 ,其动力学行为十分复杂 ,一直受到学术界和工程界广大研究者的重视和研究。本文对该领域线性和非线性研究内容及进展作了综述和讨论。

厦门港潮汐、风暴潮耦合模型

建立一个适合台湾海峡及小港湾，特别是能够反映小港湾的漫滩及潮汐、风暴潮耦合效应的数值模型，对小港湾风暴潮进行数值预报，有重要的社会和经济意义．文中以厦门港作为小港湾研究区域，在漫滩、风暴潮的耦合、开边界条件等方面对小港湾风暴潮数值计算作了一定的尝试，提出了一种能够模拟小港湾台风增水，潮位和流场变化情况的途径．