bluuebunny/crossref_metadata_2025 huggingface dataset:
DAMAGE ALONG COASTS IN SENDAI BAY CAUSED BY THE 2011 GREAT TSUNAMI
Authors: Sakai Kazuya , Uda Takaaki , San-nami Toshiro , Shimizu Tatsuya
Published: December 2012

A great earthquake with a magnitude of 9.0 occurred on March 11, 2011, with an epicenter 130 km offshore of the Oshika Peninsula in Miyagi Prefecture. After the earthquake, a giant tsunami inundated a large area along Japan's eastern coastline. We carried out field observations to investigate the damage to Arahama Town and the formation of a trench as a result of local scouring by the jet flow over the coastal dike. Here, the results of the field observations on the inundation of the tsunami into a wide residential area on Shobuta Beach and in Arahama Town were reported. Then, the destruction of the coastal dike, as well as the formation of a large trench immediately behind the coastal dike due to the tsunami overflow on the Yamamoto coast, was investigated, where the tsunami height reached up to 19.2 m above mean sea level (MSL), estimated from the run-up height on the slope of a hill.
FIELD SURVEY AND NUMERICAL ANALYSIS OF 2011 TOHOKU EARTHQUAKE TSUNAMI IN THE NORTHERN PART OF MIYAGI, JAPAN
Authors: Yasuda Tomohiro , Kakinuma Taro , Tamada Takashi , Tsujimoto Gozo
Published: December 2012

The field survey results obtained by the team of authors in the north of Miyagi Prefecture are summarized referring to a part of the survey results by other teams of the 2011 Tohoku Earthquake Tsunami Joint Survey Group. The inundation height above sea level was measured using a laser range finder with a reflection prism. The inundation height was generally larger at bay heads, as well as cave tips, except several points, which were sheltered by a peninsula or had a tapering area. The tsunamis reached inland far away from the sea along valleys and rivers. Not only steel frame buildings but also many reinforced concrete buildings were collapsed in Onagawa Town. According to the numerical simulation, the first tsunami from the west coast and the second tsunami from the east coast should come together in Utatsusaki Peninsula, which is consistent with the interviews to survivors.
A PROBABILISTIC APPROACH FOR THE WAVES GENERATED BY A SUBMARINE LANDSLIDE
Authors: Lynett Patrick J. , Martinez Arturo Jimenez
Published: December 2012

A numerical study aimed at probabilistically assessing the coastal hazard posed by tsunamis induced by one-dimensional submarine rigid landslides that experience translational failure is presented. The numerical model here utilized is the finite difference recreation of a linear, fully dispersive mild-slope equation model for wave generation and propagation. This recreated model has the capability to simulate submarine landslides that detach into multiple rigid pieces as failure occurs. An ad-hoc formulation describing the combined space-time coherency of the landslide is presented. Monte Carlo simulations are employed, with an emphasis on the shoreward-traveling waves, to construct probability of exceedance curves for the maximum dimensionless wave height from which wave statistics can be extracted. As inputs to the model, eight dimensionless parameters are specified both deterministically in the form of parameter spaces and probabilistically with normal distributions. Based on a sensitivity analysis, the results of this study indicate that submarine landslides with large width to thickness ratios and coherent failure behavior are most effective in generating tsunamis. Failures modes involving numerous slide pieces that fail in a very compact fashion, however, were observed to induce bigger waves than more coherent landslides. Rapid weakening in tsunami generation potential for some of the parameter combinations suggests that the hazard posed by submarine landslide tsunamis is strongly dependent on source features and local conditions and is only of concern for landslides of substantial dimensions.
A NUMERICAL STUDY ON LONG-WAVE GENERATION DUE TO ATMOSPHERIC-PRESSURE VARIATION
Authors: Kakinuma Taro , Fukita Kosuke
Published: December 2012

The generation and propagation of long waves due to atmospheric-pressure variation have been numerically simulated, where the atmospheric-pressure waves are assumed to travel in the eastern direction over East Chine Sea. The wave height of long waves is larger as the moving velocity of the recovery point of water surface pressed by the atmospheric pressure is close to the long-wave celerity. Before attenuation of the harbor oscillation in Urauchi Bay, Kamikoshiki Island, the incidence of long waves can continue because of the oscillation system generated between the main island of Kyushu and Okinawa Trough. The pressure profiles of atmospheric-pressure waves supposed to have concerned the large harbor oscillation in Urauchi Bay from 2009 to 2010 are classified into four patterns based on the Grid Point Value pressure data. The incident long waves causing the largest harbor oscillation in Urauchi Bay on Feb. 25, 2009 has been simulated with the estimated pressure-profile pattern, such that the largest harbor oscillation in Urauchi Bay should occur due to the atmospheric-pressure waves.
INTERACTION OF IDEALIZED URBAN INFRASTRUCTURE AND LONG WAVES DURING RUN-UP AND ON-LAND FLOW PROCESS IN COASTAL REGIONS
Authors: Goseberg Nils , Schlurmann Torsten
Published: December 2012

This paper reports experimental results of long wave run-up climbing up a 1:40 sloping beach. The resulting maximum run-up is compared with analytical results and a good agreement is found for single sinusoidal waves with uniform wave period and varying amplitude. Subsequently, the interaction with macro-roughness elements on the beach is investigated for different long-shore obstruction ratios. The reduction in wave run-up is expressed by means of a nomogram relating the wave run-up without macro-roughness elements present to those cases where on-land flow is modified by macro-roughness. The presented results mainly focus on a non-staggered and non-rotated macro-roughness
configuration. In addition to the run-up reduction, surface elevation profiles on the shore are presented, that address the shock wave generation when the wave tongue approaches the first row of macro-roughness elements.
WAVE RUNUP ON DIKES AND BEACHES
Authors: Pietropaolo Jill , Kobayashi Nobuhisa , Melby Jeffry A.
Published: December 2012

In the United States, the Federal Emergency Management Agency (FEMA) is in the process of updating its coastal flood risk maps in order to determine which locations are threatened by storm surge and wave action. These maps require the prediction of extreme wave runup. A method for predicting the runup height along the entire coast must be robust, reliable, and applicable to many different coastal features. Kobayashi et al. (2008) developed a time-average probabilistic model that predicts wave runup statistics instead of the time series of shoreline elevation. This numerical cross-shore model, CSHORE, is extended to the wet-dry zone above the still water level to predict irregular wave runup on impermeable dikes and gentle impermeable slopes. To show the CSHORE's capability in predicting runup on beaches with different geometries, the computed results from the model are compared to measured data from a variety of experiments. CSHORE is tested against 40 wave runup tests on an impermeable dike on a barred beach, 97 wave runup tests on an impermeable dike with a gently sloping beach, and 120 tests for wave runup on gentle uniform slopes. The measured 2% and 1% exceedence runup heights are predicted within errors of about 20%. The spectral significant wave height, Hmo, and a representative period are used for input to CSHORE.
The measured and computed cross-shore variations of Hmo are also computed and compared to measured data to show the capabilities and limitations of CSHORE in regards to predicting to wave transformation. Both the spectral period, Tm-1,0, and the peak period Tp at x = 0 are adapted as representative periods used in CSHORE to assess the period effect in CSHORE. The tested CSHORE is ready for practical applications such as FEMA's coastal flood mapping, and is a good practical choice because it can be used to predict beach and dune profile changes.
TSUNAMI DAMAGES OF NAKOSO COAST DUE TO THE 2011 TOHOKU TSUNAMI
Authors: Sato Shinji , Liu Haijiang , Takewaka Satoshi , Nobuoka Hisamichi , Aoki Shin-ichi
Published: December 2012

A post-2011 Tohoku earthquake tsunami survey was conducted at the Nakoso Coast, Fukushima Prefecture, Japan, on Mar 24-25 and Apr 1-2, 2011. Spatial distribution of the tsunami inundation height, together with the seawall height and damages, was investigated. We found a sharp contrast of tsunami damages within the target area; tsunami damage is the most serious in the north region (north of the Samegawa River) where seawalls with different heights played diverse roles for protection of local community. A relatively high seawall in this region kept intact after tsunami attack, and protected the lee side human properties; whereas, 71% of the low seawalls were broken during the tsunami and the disaster developed in the corresponding sheltered area. A sharp contrast at the boundary of these two types of seawalls was observed. Behind the high seawall, the tsunami intensity and velocity were significantly reduced and the inundation depth is only 0.6 m. Nevertheless, tsunami intensity was enhanced in the seawall-broken area with an inland inundation depth being 4.7 m, which ruins away the local houses. In the middle region between the Samegawa River and the Bindagawa River, the high seawall survived from the tsunami attack. We confirmed that the coastal pine tree forest, serving as a buffer zone, played a significant role in reducing the tsunami height approximately by 4 m within a cross-shore distance of 230 m. To the south of the Bindagawa River, the tsunami damage is the mildest due to the protection by the robust high seawall as well as high elevation of land topography.
WAVE RUN-UP OBSERVATION AND 2DV NUMERICAL INVESTIGATION ON BEACHES PROTECTED BY STRUCTURES
Authors: Archetti Renata , Gaeta Maria Gabriella
Published: December 2012

The main parameter for the assessment of coastal vulnerability and sediment transport is the wave run-up on the beach, defining the limit of maximum flooding, but also hydrodynamic properties in the Swash Zone (SZ) are trivial for the comprehension of hydro-morphodynamic processes. Several studies have been carried out on the SZ but few literature is still available on the run-up and on SZ flows on beaches protected by Low Crested Structures (LCSs), where flow motion is driven by a combination of low frequency infra-gravity waves and incident waves. In presence of breakwaters, swash incident waves are transmitted through the structure. In the transmission area behind the structures, wave energy is shifted to higher frequencies with respect to the incident wave spectrum and in general its mean period considerably decreases with respect to the incident one. Collecting in situ run-up measurements during storms is essential to understand the SZ processes and properly calibrate their both empirical and numerical models but measuring extreme run-up is difficult, due to the severe sea conditions and due to unexpected nature of storms. The present paper present a numerical and experimental analysis of the wave run-up and of the flow properties on a beach: the study shows the different behavior of unprotected and protected beach, subjected to the same wave conditions. In particular the paper shows that submerged breakwaters reduce in general the run-up height, on the basis of the calibrated 2DV numerical simulations, under extreme wave conditions (TR >50 years), the effect of submerged breakwaters seems to be negligible on the run-up height. Moreover a preliminary empirical equation for run-up with protected beach is proposed
FIELD RUN-UP MEASUREMENTS: CALIBRATION OF A PHYSICALLY BASED LAGRANGIAN SHORELINE MODEL
Authors: Lo Re Carlo , Manno Giorgio , Viviano Antonino , Foti Enrico
Published: December 2012

In the present contribution a measurement technique based on video imaging has been selected for the assessment of the maximum run-up. Such measurements have been used for the calibration of a numerical model and of an empirical formulation. The on-site run-up measurements have been carried out at "Lido Signorino† beach, near Marsala, Italy. The positions of the swash have been localized on a transect, normal to the shore, constituted by stakes placed at 0.5 m intervals each other. The video camera was placed orthogonally to the line of the stakes. For the numerical simulations a 1DH Boussinesq-type of model for breaking waves has been applied which takes into account the wave run-up by a Lagrangian shoreline model. In such simulations monochromatic waves have been propagated in a numerical flume having the same beach slope of the measured transect. The comparison between registered and estimated run-up have underlined an acceptable agreement. In particular, it has been obtained that the numerical model tends to underestimate the run-up, instead the applied empirical formula gives overestimated values.
PHYSICAL MODEL AND REVISION OF THEORETICAL RUNUP
Authors: De la Peña Jose , Sanchez Jose , Diaz Roberto , Martin Manuel
Published: December 2012

Several formulations deduced from empirical studies are available for runup estimation. Scattering is high when applied to practical cases. Through a state of the art best formulations are chosen. This equations are also studied in a physical model carried out in the Laboratory for Maritime Experimentation of CEDEX with three beaches with slopes 1/20, 1/30 and 1/50 and with sand bed. The performance of each formulation is discussed. A new formulation is proposed in order to give more weight to the beach slope thus reducing scatter.
BED STRESS INVESTIGATION UNDER BREAKING SOLITARY WAVE RUNUP
Authors: Adityawan Mohammad Bagus , Tanaka Hitoshi , Lin Pengzhi
Published: December 2012

The bed stress under breaking solitary wave runup was investigated in this study using the Simultaneous Coupling Method (SCM). The SCM couples the shallow water equation (SWE) with k-w model. The depth averaged velocity from SWE is applied as the upper boundary condition in k-w model for bed stress assessment from the boundary layer. It was found that the boundary layer approach provides more accurate bed stress estimation than the empirical method, which leads to a more accurate prediction of runup and wave profile. The accumulation of bed stress in during solitary wave runup was evaluated. The bed stress on the direction leaving the shoreline will have more impact in the overall process. However, during a short period of run up process, bed stress toward the shoreline may have significant effect as well.
LOW FREQUENCY WAVE RESONANCE IN FRINGING REEF ENVIRONMENTS
Authors: Pomeroy Andrew William Mackay , Van Dongeren Ap , Lowe Ryan , Van Thiel de Vries Jaap , Roelvink Jan
Published: December 2012

Low frequency wave resonance has been postulated to enhance damage to coral reef protected coastlines during storm events. This paper uses the numerical model XBeach to examine the dynamics that contribute to resonance that have been previously observed on a fringing reef on Guam during tropical storm Man-Yi (Péquignet et al., 2009). The methods to identify resonance in numerical (or field data) are comprehensively reviewed with three indicators of resonance proposed based upon data obtained at two locations in the model domain: 1. The water surface elevation must be highly coherent, 2. The phase difference must (closely) correspond to 0° or 180°, and 3. Amplification of the signal must be observed between the reef crest and the shoreline. XBeach simulations demonstrated that resonance could be reproduced under 'normal' wave conditions, but only when bottom friction was minimal and hence values that were atypically low for coral reefs. However, under tropical storm Man-Yi conditions, resonance was reproduced with reasonable bottom friction values. A sensitivity analysis demonstrated that, although the frequency associated with resonance was not affected by the choice of bottom friction coefficients, the magnitude of the amplification was significantly affected. Ongoing research is being undertaken to investigate the resonant response for a wider variety of reef morphologies and incident wave forcing conditions.
MODELLING WAVE TRANSFORMATION ACROSS A FRINGING REEF USING SWASH
Authors: Zijlema Marcel
Published: December 2012

This paper presents the application of the open source non-hydrostatic wave-flow model SWASH to wave propagation over a fringing reef, and the results are discussed and compared with observations obtained from a laboratory experiment subjected to various incident wave conditions. This study focus not only on wave breaking, bottom friction, and wave-induced setup and runup, but also on the generation and propagation of infragravity waves beyond the reef crest. Present simulations demonstrate the overall predictive capabilities of the model for a typical coral reef with steep slopes and extended reef flats.
NON-HYDROSTATIC MODELLING OF INFRAGRAVITY WAVES USING SWASH
Authors: Rijnsdorp Dirk Pieter , Smit Pieter Bart , Zijlema Marcel
Published: December 2012

This paper presents numerical modelling of the nearshore transformation of infragravity waves induced by bichromatic wave groups over a horizontal and a sloping bottom. The non-hydrostatic model SWASH is assessed by comparing model predictions with analytical solutions over a horizontal bottom and with detailed laboratory observations for a sloping bottom. Good agreement between model predictions and data is found throughout the domain for bound infragravity waves. Furthermore the model predicts greater outgoing free infragravity wave-heights for steeper slope regimes which is consistent with the measurements. The model however tends to overestimate the magnitude of the outgoing infragravity waves.
FULLY NONLINEAR BOUSSINESQ-TYPE MODELLING OF INFRAGRAVITY WAVE TRANSFORMATION OVER A LOW-SLOPING BEACH
Authors: Tissier Marion , Bonneton Philippe , Ruessink Gerben , Marche Fabien , Chazel Florent , Lannes David
Published: December 2012

Recent field studies over low sloping beaches have shown that infragravity waves could dissipate a significant part of their energy in the inner surf zone. This phenomenon and the associated short- and long-wave transformations are not well-understood. In this paper, we assess the ability of the fully nonlinear Boussinesq-type model introduced in Bonneton et al. (2011) to reproduce short and long wave transformation in a case involving a strong infragravity wave dissipation close to the shoreline. This validation study, based on van Dongeren et al. (2008)'s laboratory experiments, suggests that the model is able to predict infragravity wave breaking as well as the complex interactions between short and long waves in the surf zone.
MODELLING INFRAGRAVITY WAVES AND CURRENTS ACROSS A FRINGING CORAL REEF
Authors: Van Dongeren Ap , Lowe Ryan , Pomeroy Andrew , Duong Trang Minh , Roelvink Dano , Symonds Graham , Ranasinghe Roshanka
Published: December 2012

Low-frequency (infragravity) wave dynamics on a fringing coral reef were investigated using the numerical model XBeach (Roelvink et al, 2009). First, the skill of the one-dimensional model was evaluated based on its predictions of short waves (0.04-0.2 Hz), infragravity waves (0.004-0.04 Hz) and water level measurements (tidal and wave setup) obtained during a 2009 field study at Ningaloo Reef in Western Australia. The model calibration was sensitive to friction coefficients for short waves and current / infragravity bed friction, which were assumed independent in this model study. The infragravity waves were found to be generated primarily in the surf zone through the breakpoint generation mechanism rather than through offshore forcing. The infragravity waves were strongly also modulated over the reef by tidal depth variations, primarily due to the variability in frictional dissipation rates when the total water depth over the reef varied. The results reveal that short waves dominated bottom stresses on the fore reef and near the reef crest; however, inside the lagoon, infragravity waves become increasingly dominant, accounting up to 50% of the combined bottom stresses
FULL PARTICLE PIC MODELLING OF THE SURF AND SWASH ZONES
Authors: Kelly David Matthew
Published: December 2012

In this paper a hybrid Eulerian Lagrangian solver based on the full-particle Particle-In-Cell (PIC) method is outlined. The solver is capable of simulating incompressible free-surface flows in domains with arbitrary, free-slip, solid boundaries. The flexibility of the approach allows for simulation of wetting and drying and pooling as well as wave breaking, splash-up over complex obstacles and the overtopping of coastal structures. The method has been validated for a wide variety of test cases and results are in good agreement with the numerical and experimental results of other researchers.
APPLICATION OF A TVD SOLVER IN A SUITE OF COASTAL ENGINEERING MODELS
Authors: Shi Fengyan , Ma Gangfeng , Kirby James T. , Hsu Tian-Jian Tom
Published: December 2012

This paper describes the recent developments in a suite of coastal engineering models using Godunov-type shock-capturing schemes. The developments include a depth-integrated, wave resolving Boussinesq model, a hydrostatic, wave-averaged circulation model, and a fully 3-D non-hydrostatic model in a surface-following $\sigma$ coordinate formulation. The models implemented with the shock-capturing TVD scheme show robust performances in modeling breaking waves, nearshore circulation and coastal inundation. In this paper, we present model equations in a conservative form, MUSCLE-TVD numerical scheme and model applications. We also point out some problems caused by the TVD scheme in the recent model applications.
BEACH INUNDATION PREDICTION DURING STORMS USING DIFFERENT WAVE HEIGHTS AS INPUTS
Authors: Sancho Amanda , Guillén Jorge , Simarro Gonzalo , Medina Raúl , Cánovas Verónica
Published: December 2012

Beach inundation prediction is evaluated at an artificial, tideless embayed beach located in the city of Barcelona (NW Mediterranean, Spain). To this end, inundation measurements using video observations are compared with estimations including the tidal variations and the wave runup formulation of Stockdon et al. (2006), introducing deep water, local wave measurements and local wave computations as inputs. As the observations consider the mean runup and the estimations use the 2% runup exceedance (R2%), the inundation is overestimated if any of the wave heights in the formulation are used. Nonetheless, results are improved if a local wave height at 10 m depth is used, in particular for waves approaching the shore obliquely. Finally, it is stated that the differences between the observations and the estimations vary along the beach, being higher in the curved zone of the embayment.
NUMERICAL AND EXPERIMENTAL DESCRIPTION OF THE FLOW, BOUNDARY LAYER AND BED EVOLUTION IN BORE-DRIVEN SWASH ON A COARSE SEDIMENT BEACH
Authors: Briganti Riccardo , Dodd Nicholas , Pokrajac Dubravka , O'Donoghue Tom
Published: December 2012

The paper presents the results of a comparison between a fully coupled numerical model for the hydro- and morphodynamics of the swash zone. The model solves simultaneously the Non-Linear Shallow Water Equations and the Exner equation for the bed updates. The model uses the simple Grass formula for the sediment transport and the momentum integral method for the bottom shear stress prediction. The laboratory tests were carried out at the University of Aberdeen swash facility and aimed at studying the hydrodynamics and sediment transport of a single, bore-generated swash event. The comparison is carried out in terms of water depth and horizontal velocity (depth average and profiles) and sediment transport. The model performs well in predicting these quantities, above all during the run-up.
MODELLING OVERWASH AND INFILTRATION ON GRAVEL BARRIERS
Authors: McCall Robert Timothy , Masselink Gerd , Roelvink Dano , Russell Paul , Davidson Mark , Poate Timothy
Published: December 2012

A quasi-3D process-based and time dependent groundwater model is developed and coupled to a hydrodynamic storm impact model to simulate the effect of infiltration on overwash on a gravel barrier. The coupled model is shown to accurately reproduce groundwater variations, runup properties and overwash time series measured in the gravel barrier during a large-scale physical model experiment. The coupled model is applied to study the influence of hydraulic conductivity on overwash volumes. It is shown that modeled overwash volumes are significantly affected by infiltration for hydraulic conductivity values greater than 0.01ms-1.
LAGRANGIAN DRIFTER MODELLING OF AN EXPERIMENTAL RIP CURRENT
Authors: Suarez Leandro , Cienfuegos Rodrigo , Barthélemy Eric , Michallet Hervé , Escauriaza Cristian
Published: December 2012

A non-uniform alongshore wave forcing on an experimental uneven mobile bathymetry create mean circulation on a rip channel. A 2D numerical hydrodynamic model that integrates the non-linear shallow-water equations in a shock-capturing finite-volume framework is used to validate the nearshore circulation, and drifters displacement.
A FIELD AND NUMERICAL STUDY INTO RIP CURRENTS IN WIND-SEA DOMINATED ENVIRONMENTS
Authors: Winter Gundula , Van Dongeren Ap , De Schipper Matthieu , Van Thiel de Vries Jaap
Published: December 2012

Rip currents are wave-induced and off-shore directed flows which occur frequently in the surf zone and can pose a serious threat to swimmers. While the behaviour of rip currents has been studied in swell-dominated environments, less is known about their characteristics in wind-sea dominated environments. This study aims to improve the knowledge on rip currents in these environments such as the Dutch coast. In a field campaign at Egmond aan Zee (The Netherlands), Lagrangian velocities in the surf zone were measured with drifter floats. An extensive dataset of rip current measurements was collected from which parameters that initiate rip currents and affect their mean flow properties were identified. Numerical simulations with XBeach aided to understand and confirm the observations made in the field. A reduction of the hydrodynamic parameters along with simplification of the bathymetry in the model allowed for identification of the governing rip current parameters, which can be the basis for a warning system.
SPH MODELING OF MEAN VELOCITY CIRCULATION IN A RIP CURRENT SYSTEM
Authors: Jalali Farahani Rozita , Dalrymple Robert A. , Hérault Alexis , Bilotta Giuseppe
Published: December 2012

A Lagrangian numerical model called Smoothed Particle Hydrodynamics is used to analyze rip current system generated by a single bar and a rip channel. The pattern of the wave-induced circulation cell over the bar, the oppositely-rotating circulation cell on-shore and a strong seaward-directed current in the rip channel is modeled numerically. The mean horizontal variations of rip current system as well as three-dimensional circulations are studied. The results in three-dimensional space reveal the wave-current interaction and flow patterns in different parts of rip channel, bar, and the trough located near shore. For comparison to experimental data, Eulerian nodes are introduced to the numerical model and SPH interpolation over neighboring Lagrangian particles is implemented to find fluid parameters at those specific nodes. This methodology leads to a better understanding of depth-integrated flows and a more accurate comparison of numerical results with experimental results. Model predictions are compared to laboratory measurements of Drønen et al. (2002) and show good agreement, including mean velocity profiles, mean surface elevation and three-dimensional velocity components.
RIP CURRENTS ON A BARRED BEACH
Authors: Ruju Andrea , Higuera Pablo , Lara Javier L. , Losada Inigo J. , Coco Giovanni
Published: December 2012

This work presents the numerical study of rip current circulation on a barred beach. The numerical simulations have been carried out with the IH-FOAM model which is based on the three dimensional Reynolds Averaged Navier-Stokes equations. The new boundary conditions implemented in IH-FOAM have been used, including three dimensional wave generation as well as active wave absorption at the boundary. Applying the specific wave generation boundary conditions, the model is validated to simulate rip circulation on a barred beach. Moreover, this study addresses the identification of the forcing mechanisms and the three dimensional structure of the mean flow.
2011 TOHOKU TSUNAMI RUNUP AND DEVASTATING DAMAGES AROUND YAMADA BAY, IWATE: SURVEYS AND NUMERICAL SIMULATION
Authors: Okayasu Akio , Shimozono Takenori , Sato Shinji , Tajima Yoshimitsu , Liu Haijiang , Takagawa Tomohiro , Fritz Hermann M.
Published: December 2012

Distributions of inundation and runup height for the 2011 off the Pacific coast of Tohoku Earthquake Tsunami were measured in and outside Yamada Bay located at the center of Iwate Prefecture, Japan. Numerical simulations were conducted to reproduce flow, inundation and runup height distributions. Surface elevation profiles recorded by the GPS wave gauges were used as the offshore boundary condition. In order to investigate characteristics of tsunami response to different geomorphological features, frequency separation was tried for the tsunami incident wave. It was found that the high frequency component was responsible for large tsunami height at narrow inlets and open bays, whereas the low frequency component had significant influence for inundation in closed bays.
INCORPORATION OF CONTINENTAL AND URBAN RUN-OFF INTO A COASTAL CIRCULATION MODEL: APPLICATION TO THE CATALAN COAST
Authors: Liste Maria , Grifoll Manel , Keupers Ingrid , Monbaliu Jaak , Espino Manuel
Published: December 2012

A 3D hydrodynamical model has been set up to incorporate the continental and urban run-off into the Catalan Coastal waters. Particular attention was paid to introducing correctly the freshwater plumes and attention was also paid to determinate the influence of the land discharge profile with regard to the distributed continental run-off. The model domain includes a small part of the Catalan Coast where the combination of local land topography with torrential rainfall caused considerable local runoff on a short period of time with a large impact on the receiving coastal waters.
The Regional Ocean Modeling System (ROMS) simulations were used to examine the dispersal to a freshwater delivery from two relevant event; a low river discharge typical of mean conditions during April 2011 and a high discharge representative of the storm event during March 2011 are considered. We have observed the plume responses to an abrupt change in river discharge. During the mean conditions, low salinity water is concentrated around the rivers mouth while during the flood event, the plume spread offshore in the direction of river water outflow and turned downstream close to the coast. The differences between a simulation including the river outflow as a land forcing and a simulation including river and urban runoff as a land forcing suggested that the urban runoff plays an important role in the spreading and shape of the river plume.
CURRENT CHARACTERISTICS IN THE PRESENCE OF NEAR-ORTHOGONAL WAVES
Authors: Lim Kian Yew , Madsen Ole Secher , Cheong Hin Fatt
Published: December 2012

An experimental study involving near-orthogonal wave-current interaction in a wave basin is reported in this paper. Due to previous shortcomings associated with 2D bottom configurations, i.e. occurrence of ripple-induced turning of flows close to the bed, the present experiments were conducted with the bottom covered by closely packed ceramic marbles (mean diameter of 1.25cm). Three types of flows were generated over this bottom: current-alone, wave-alone and combined wave-current flow. For current-alone and wave-current cases, the log-profile analysis was used to resolve the equivalent Nikuradse sand grain roughness, kn, while the energy dissipation method was used to estimate kn for wave-alone case. The results show that kn obtained for current- and wave-alone tests is roughly 2.2 times the diameter of the marbles. For orthogonal wave-current flows, the kn value, when used in combination with the Grant-Madsen (GM) model to reproduce the experimental apparent roughness, is found to be smaller than the measured current-alone and wave-alone kn. Similar under-prediction of bottom roughness is also observed when the GM model is compared with a numerical study, thus supporting the conjecture that when the current is weak compared to the waves, simple theoretical models like GM are not sufficiently sensitive to the angle of wave-current interaction. Experiments with currents at angles of 60° and 120° to the wave direction yield apparent roughness smaller than the 90° case, which is counter-intuitive since one would expect the mean flow to experience a stronger wave-induced turbulence when it is more aligned with the wave direction. This result indicates a possible contamination from wave-induced mass transport to the mean flow profile for non-orthogonal combined flow cases, and therefore highlights the need for other alternatives to the log-profile analysis when attempting to resolve kn from current velocity profiles from combined wave-current flows.
PREDICTIONS OF CIRCULATING CURRENT FIELD AROUND A SUBMERGED BREAKWATER INDUCED BY BREAKING WAVES AND SURFACE ROLLERS
Authors: Tajima Yoshimitsu
Published: December 2012

This paper develops a quasi-three-dimensional nearshore current model which accounts for excess shoreward volume fluxes due to waves and surface rollers. The model splits the water column at the wave trough level and solves two different layers of 2DH momentum equations. The first layer covers above the trough level and determines the shear stress at the trough level while the the second layer covers over the entire depth and determines the volume flux due to mean current components. Linearly approximated vertical profile of the shear stress and corresponding turbulent eddy viscosity model enables the present model to yield analytical explicit expression of the horizontal velocity profiles, which enhance computational efficiency of the model. The extended model was applied to predictions of longshore current velocity on the long straight beach and circulation current patterns behind the detached submerged breakwater on the plane beach. Excellent agreement between model predictions and measurements supports the validity of the model and importance of quasi-three-dimensional features around the submerged break water.
WAVE-INDUCED SETUP INSIDE PERMEABLE STRUCTURES
Authors: Wellens Peter , Van Gent Marcel
Published: December 2012

Coastal protection of land reclamation areas is often composed of rock or otherwise permeable material. Wave-induced setup inside permeable structures can be a problem for land reclamation areas if the design land level is too low. Wave-induced setup has not been studied extensively. In this study we use COMFLOW, a numerical model based on the Navier-Stokes equations employing the Volume-Of-Fluid method to displace the free surface, to quantify wave-induced setup inside permeable structures. The results are summarized in a conceptual design formula to determine wave-induced setup as a function of wave height Hm0 and rock diameter Dn50.
LOADING OF VERTICAL WALLS BY OVERTOPPING BORES USING PRESSURE AND FORCE SENSORS - A LARGE SCALE MODEL STUDY
Authors: Ramachandran Karunya , Genzalez Rebeca Roldan , Oumeraci Hocine , Schimmels Stefan , Kudella Matthias , Van Doorslaer Koen , De Rouck Julien , Versluys Tom , Trouw Koen
Published: December 2012

This study is based on the data obtained from tests carried out in the Large Wave Flume (Grosser Wellenkanal (GWK)) in Hannover in the frame of a joint research project of Ghent University (Belgium) and Forschungszentrum Kuste (FZK, Germany). The goal of the research project is to determine the wave induced loads on vertical storm walls located at the end of overtopped dike, which are designed to protect coastal cities from overtopping and floods. The loads resulting from waves overtopping the dike and impacting the vertical wall as a bore are measured by means of both force and pressure sensors. This paper describes the results of pressure and force records at the vertical wall, including a comparative analysis of the overall forces obtained by pressure integration and force sensors for two different wall setups: Fully blocked wall and partially blocked wall.
MECHANISM AND COUNTERMEASURES OF WAVE OVERTOPPING FOR LONG-PERIOD SWELL IN COMPLEX BATHYMETRY
Authors: Kashima Hiroaki , Hirayama Katsuya
Published: December 2012

Recently, coastal disasters due to long-period swells induced by heavy storms and catastrophic typhoons have increased at Japanese coasts and harbors. Long-period swells are more susceptible to the bottom bathymetry of the offshore deep water region and their wave heights locally increase due to the concentration of wave energy caused by the complex bottom bathymetry in the relatively shallow water region. In addition, the wave overtopping rate may increase due to the long waves in front of the seawall induced by the long-period swells. However, the spatial relationship between wave characteristics and wave overtopping discharges in the complex bathymetry are not well known owing to a lack of detailed measurements. In this study, model experiments were conducted by using a large basin to investigate the spatial characteristics of wave transformation and wave overtopping focusing on the heavy wave overtopping damages caused by the arrivals of long-period swells at the Shimoniikawa Coast in 2008. Effective countermeasures against wave overtopping are also discussed based on their characteristics.
OVERTOPPING FLOW PROPERTIES CHARACTERIZATION IN LABORATORY AND PROTOTYPE THROUGH THE COMBINATION OF NON INTRUSIVE INSTRUMENTAL TECHNIQUES
Authors: Llana Alberto , Molina Rafael , Camarero Alberto , Campos Alvaro , Alises Ana Francisca , López José Damián
Published: December 2012

Overtopping events may cause different failure modes depending on overtopped flow characteristics. Most of the studies about overtopping hazard analysis link the damages caused by the overtopping event to its mean overtopping discharge (q), which provides no information about overtopped flow characteristics or its spatial distribution. In this paper it is presented a non intrusive measurement system based on video imagery techniques and optical level sensors (OLS), which aim is to obtain overtopped highly aerated flows´ principal characteristics: velocity, volume, and density, in order to deep in the knowledge of this phenomenon, and minimizing the damages that it may cause to port´s infrastructures and exploitation
ELEVATED WATER LEVELS AT TRAINED RIVER ENTRANCES
Authors: You Zai Jin , Nielsen Peter , Hanslow David , Pritchard Tim
Published: December 2012

The south-east coast of Australia has many low-lying areas at river entrances that are vulnerable to coastal inundation due to high water levels elevated by ocean tides, coastal storms, ocean waves and other drivers. The penetration of elevated entrance water levels into rivers can further intensify river flooding associated with high rainfall events. In this study, historical water level data, which were collected continuously at 17 inshore and 5 offshore permanent tide stations along the East Coast of Australia, are used to study effects of tides and waves on water levels at trained river entrances and also to estimate extreme entrance water levels without major entrance rainfall-related flooding.
LAGRANGIAN MEASUREMENTS OF TURBULENT DISSIPATION OVER A SHALLOW TIDAL FLAT FROM PULSE COHERENT ACOUSTIC DOPPLER PROFILERS
Authors: Mullarney Julia C , Henderson Stephen M
Published: December 2012

We present high resolution (25 mm spatial, 8 Hz temporal) profiles of velocity measured over a shallow tidal flat using pulse-coherent Acoustic Doppler Profilers mounted on surface drifters. The use of Lagrangian measurements mitigated the problem of resolving velocity ambiguities, a problem which often limits the application of high-resolution pulse-coherent profilers. Turbulent dissipation rates were estimated from second-order structure functions of measured velocity. Drifters were advected towards, and subsequently trapped on, a convergent surface front which marked the edge of a freshwater plume. Measured dissipation rates increased as a drifter deployed within the plume approached the front. A drifter then propagated with and along the front as the fresh plume spread across the tidal flats. Near-surface turbulent dissipation measured at the front roughly matched a theoretical mean-shear-cubed relationship, whereas dissipation measured in the stratified plume behind the front was suppressed. After removal of estimates affected by surface waves, near-bed dissipation matched the velocity cubed relationship, although scatter was substantial. Dissipation rates appeared to be enhanced when the drifter propagated across small subtidal channels.
THE EFFECT OF A SUBMARINE CANYON ON TSUNAMI PROPAGATION IN THE GULF OF ARAUCO, CHILE
Authors: Aranguiz Rafael
Published: December 2012

The 2010 Chile tsunami affected the entire coast of the Biobio Region, where several bays were flooded, and seawater surged hundreds of meters into rivers. However, no inundation occurred in the 2km wide Biobio River, located at the northern entrance of the Gulf of Arauco. Likewise, minimal inundation (less than 2m) was found on the gulf's eastern coast, just south of the river mouth. The study was done by means of numerical simulation with TUNAMI code. Four (4) nested grids with 81†, 27†, 9† and 3† resolution were defined. Several scenarios were simulated, including the 1730, 1835, 1960 and 2010 events. The first two scenarios considered only a uniform rupture zone, while the others were defined using non-uniform initial condition. Another set of simulations were run without the presence of the island and with a modified bathymetry, so that its effect on tsunami propagation could be studied. It can be concluded that the Biobio canyon is very important in tsunami propagation in the Gulf of Arauco. There is a mitigation effect on the eastern side of the Gulf due to the refraction and dispersion generated by its presence. The change in wave direction is enhanced due to wave diffraction generated by the Santa María Island, causing the wave fronts to move in a north-south direction, preventing severe damage to the eastern side. However a direct impact of the tsunami in the southern end of the Gulf can be observed.
THE INFLUENCE OF EXTREME EVENTS ON HYDRODYNAMICS AND SALINITIES IN THE WESER ESTUARY IN THE CONTEXT OF CLIMATE IMPACT RESEARCH
Authors: Zorndt Anna C. , Schlurmann Torsten , Grabemann Iris
Published: December 2012

The salinity and its longitudinal distribution in the Weser estuary, Germany, has implications for water management as the estuarine water is needed, e.g., for irrigation of the agricultural used hinterlands and as industrial water and because of its intrusion into groundwater. Generally, the salinity distribution is determined by tidal dynamics, river runoff from the catchment area, amount of intruding seawater from the German Bight (North Sea) as well as by the salinities of both river and seawater. Anthropogenic climate change may have an impact on the estuarine dynamics and, thus, on the salinity distribution. This study focuses on the impact of storm surges. A semi-implicit Eulerian-Lagrangian finite element model was used to simulate hydrodynamics and salinities in the estuary. By comparing simulated and observed data of two past storm surges it is shown that the model is well capable of reproducing estuarine dynamics. Possible future changes due to climate change are investigated for three scenario-
based storm surges; two of them represent future storm conditions and one specifies reference (today's) conditions for comparison. These storm surges were simulated using boundary conditions from water level simulations with a hydrodynamic model for the North Sea together with the respective meteorological forcing. It can be shown that during storm tides, isohalines penetrate more than 30 km further upstream than during normal conditions. For the most severe scenario-based storm surge, this leads to a salinity increase of up to 30 psu within the mixing zone during the highest storm tide.
COMPREHENSIVE NUMERICAL SIMULATION OF WAVES CAUSED BY TYPHOON USING A METEOROLOGY-WAVE-STORM SURGE-TIDE COUPLED MODEL
Authors: Ohira Koichiro , Shibayama Tomoya , Esteban Miguel , Mikami Takahito , Takabatake Tomoyuki , Kokado Makito
Published: December 2012

The present study focuses on the risks of storm surge caused by future increases in typhoon intensity due to climate change. These risks were analyzed by integrating weather, wave, storm surge and tide prediction systems into a new simulation methodology. This model, which the authors developed by themselves, makes it possible to calculate the weather fields of typhoons in the past as well as in the future on the basis of meteorology and can simulate waves in a complex geographical area, in contrast with many previous storm surge simulation methods which were not based on accurate meteorological models. The model was verified to accurately reproduce historical typhoons and waves and thus is a useful tool for the analysis of future climate risks.
EXTREME WATER LEVEL EXCEEDANCE PROBABILITIES AROUND AUSTRALIA
Authors: MacPherson Leigh , Haigh Ivan David , Mason Matthew , Wijeratne Sarath , Pattiaratchi Charitha , George Steve
Published: December 2012

The potential impacts of extreme water level events on our coasts are increasing as populations grow and sea levels rise. To better prepare for the future, coastal engineers and managers need accurate estimates of average exceedance probabilities for extreme water levels. In this paper, we estimate present day probabilities of extreme water levels around the entire coastline of Australia. Tides and storm surges generated by extra-tropical storms were included by creating a 61-year (1949-2009) hindcast of water levels using a high resolution depth averaged hydrodynamic model driven with meteorological data from a global reanalysis. Tropical cyclone-induced surges were included through numerical modelling of a database of synthetic tropical cyclones equivalent to 10,000 years of cyclone activity around Australia. Predicted water level data was analysed using extreme value theory to construct return period curves for both the water level hindcast and synthetic tropical cyclone modelling. These return period curves were then combined by taking the highest water level at each return period.
PIV MEASUREMENTS OF PARTICLE VELOCITIES AND TRAJECTORIES FOR INTERNAL WAVES PROPAGATING IN A TWO-LAYER FLUID ON A SLOPING BOUNDARY
Authors: Umeyama Motohiko , Nguyen Kim-Cuong
Published: December 2012

Some characteristics of internal waves propagating in a two-layer fluid on a sloping bottom were investigated experimentally using particle image velocimetry (PIV) that was originally developed to express the velocity field in a two-dimensional area. Two dimensional vector distributions of velocity were estimated at several phases during one wave cycle. The method of characteristics was adapted to calculate the interfacial displacement and water particle trajectory. In addition, the variations of wave speed, wave height and wave setup from deepwater to shallow-water regions by an imaging technique were compared with those by a wave dissipation model based on the radiation stress concept. These attempts proved the ability of the imaging technique to accurately measure both temporal and spatial variations of some physical quantities due to the propagation of internal waves. The PIV technique was applied to the prediction of Lagrangian velocity in a Eulerian scheme. The measured particle path was compared with the positions found theoretically by the method of characteristics.