Wave Numerical Simulation

Probabilistic methods enable the modelling of the uncertainties associated with the integrity assessment of structures containing defects to be taken into account. This paper presents a critical review of recent developments in the probabilistic modelling of the uncertainties associated with fatigue and fracture reliability assessment.

This paper investigates the use of a shifting algorithm for improving the results of smoothed particle hydrodynamics (SPH) multi-phase simulations by preventing the creation of unnatural voids. Particle shifting occurs according to a Fickian-based algorithm so particles maintain a nearly uniform distribution. A modification of the shifting algorithm is necessary in the air phase to avoid unphysical void formation. In conjunction with the use of graphics processing units (GPUs) for the acceleration of the simulation, the new shifting algorithm allows the simulation of complex multi-phase flows such as a wet dam break and a sloshing tank. Finally, the shifting algorithm is extended to 3-D and validated with the SPHERIC benchmark test case of dam break impacting an obstacle.

Direct torque control (DTC) is known to produce quick and robust response in alternating current drives. However, during steady state, notable torque and flux ripple occur. They are reflected in speed estimation, speed response and also in increased noise. The electrically excited alternating current induction motor has typically small synchronous inductance values and quite low transient values because of the damper windings mounted on the rotor therefore the torque and stator flux linkage ripples are high in conventional direct torque control due to the implementation of hysteresis control. In this paper, an attempt is made to address this problem using direct torque control scheme with space vector pulse width modulation scheme. It is based on the compensation of the stator flux linkage vector error using the space vector modulation in order to decrease the torque and flux linkage ripples and produced fixed switching frequency under the principle that the torque is controlled by the torque angle on alternating current induction motor. The alternating current induction motor is supplied by a two level thyristor inverter powered by space vector modulation. Conventional principles of direct torque control and space vector pulse width modulation were described. It can be used in various applications like electric vehicles, and industrial control where field weakening operation is required. Simulation research is carried out in Matlab/Simulink which illustrates steady state and dynamic performances of the developed system. Simulation results demonstrate the validity and effectiveness of the torque control response which properly combines with space vector pulse width modulation that shows faster dynamic response, lower torque ripple and lower flux ripple. Moreover, simple Matlab/Simulink model is introduced for two level space vector modulation inverter which can be realized and implemented in practice for three phase alternating current induction.

— When considering the interaction of waves with a conventional submerged breakwater, the incident wave energy can be split into: a reflected fraction; a dissipated fraction, due to the wave breaking and the friction losses on it; and a transmitted fraction to the shore. If the submerged breakwater embeds a wave energy absorption device, a further reduction of the transmitted energy can be achieved, improving the coastal protection performance of the structure. This is the case of the REWEC1, which is a submerged breakwater embedding an OWC device designed for operating under resonance flow conditions with the most probable sea state of a specific site. In this work, a CFD approach has been used in order to evaluate the response, in terms of reflection and transmission coefficients, of these submerged breakwater systems operated inside a wave flume, under regular waves generated by a piston type wave maker. The water-air interaction is taken into account by means of the Volume Of Fluid (VOF) model implemented in the commercial CFD code Ansys Fluent. Both air and water flow fields are assumed to be unsteady and are computed solving the RANS equations. The results confirm a reduction of the transmission coefficient in the case of the REWEC1.

We investigate the wave energy potential in the Caribbean Sea using a 30-year wave hindcast. Wave energy in enclosed sea basins, such as the Gulf of Mexico and the Caribbean Sea, is commonly associated with lower energy production rates. However, an easterly zonal wind reaching 13 m/s, known as the Caribbean Low-Level Jet (CCLJ), is shown to control the wave climatology in the Caribbean Sea. The wave hindcast information is validated with altimetry (Globwave) and buoy (DIMAR) data from the Colombian Caribbean Sea. The wave hindcast performance is very satisfactory at two buoy locations (Barranquilla and Providencia) and with respect to altimetry information, but presents an underprediction of extreme events at Puerto Bolivar. Therefore, an assessment of wave energy in the study area, based on wave hindcast information, is conducted to investigate the wave energy potential in such enclosed area. Numerical results suggest that the CLLJ region is suitable for wave energy extraction (8–14 kW/m) and presents important spatial gradients that need to be considered for the installation of wave energy devices. Furthermore, it is found that locally generated (sea) wave energy can be suitable for energy production and hence future technology development should be devoted to its harvesting.

According to the instant development of maritime transport all over the world, Myanmar, as a developing country, also needs to upgrade existing ports and to construct new deep sea ports for larger vessels. There are some potential areas for deep sea port project along Myanmar coastline. Due to the absence of long-term in-situ data and high cost of wave measurements, coastal engineers have to estimate wave characteristics using a variety of methods, which involve empirical and numerical solutions. The main purpose of this research is to predict the wave characteristics for coastal regions of Myanmar by using a third-generation numerical wave model SWAN (Simulating WAves Nearshore). In this article, the generation of waves by a constant wind filed blowing over a fetch limited area is presented firstly and the results are compared with empirical formulae for validation. The simulated wave parameters are well agreed with the results from empirical equations. And then, numerical simulation is carried out with actual wind field for the duration of average maximum wind speed in the Bay of Bengal in monsoon season. The calculated results are compared with the ECMWF (European Centre for Medium-Range Weather Forecasts) ERA-Interim reanalysis data sets. Finally, the wave characteristics for future port development areas are predicted.

• Analytical and numerical models to study sound transmission through a periodically voided soft elastic medium are developed, in which the analytical model is based on effective medium approximation theory. • Attenuation of sound transmission through the periodically voided elastic medium is shown to be related to the monopole resonances of the voids. • The effect of strong and weak coupling of cylindrical void resonances on transmission characteristics is presented. a b s t r a c t Analytical and numerical models are developed to study sound transmission through a periodically voided soft elastic medium submerged in water. The analytical model is based on homogenisation theory which allows modelling of the voided material as a homogeneous material using effective material parameters. The numerical model is based on the finite element method. A single layer of voids as well as multiple layers of voids along the direction of propagation of sound are considered. Attenuation of sound pressure is attributed to the monopole type resonance of the voids. The effect of strong and weak coupling of void resonances on the transmission characteristics is presented. Strong coupling of resonance of voids is shown to result in broadband attenuation of sound. The advantages and limitations associated with each predictive technique are briefly discussed.

Continuing our previously published work, plunging wave breaking over relatively mild sloping
beach-type formations is investigated in this paper. Numerical modeling aspects on the matter
are discussed, by pursuing comparisons against experimental data. The modern robust method
Smoothed Particle Hydrodynamics is used and the recently enhanced version of the academic
‘open source’ code SPHysics v.2 is being validated. Spatial resolution is discerned as the most
crucial factor in forming plausible results. Exquisite visual representation of the violent freesurface
deformations is further upheld by coincidence of numerical and experimental results of
classic and sophisticated flow characteristics, in terms of wave heights, ensemble-averaged
values of hydrodynamic features, Fourier spectral analysis of turbulent velocities, vorticity
patterns and wave-induced mean flows. Further need to verify the model’s ability to capture the
near-shore wave breaking dynamics and surf/swash zone turbulence sets the path of future
research, based on extremely refined simulations with a new ‘parallel’ version of SPHysics.

A two-dimensional high order Boussinesq-type model is presented to simulate wave propagation in the nearshore zone. The model is extended to the surf zone through the eddy viscosity concept and to the swash zone by applying a modified narrow slot technique. Bottom friction and subgrid turbulent mixing are also incorporated. The numerical model relies on a generalized multi-step predictor-corrector scheme. Both the 1DH and 2DH model versions are verified with a number of experimental cases involving regular and irregular wave propagation. A comparison with a SPH model is also included. The agreement, in general, is satisfactory and most of the nearshore phenomena are accurately reproduced.

In this paper, a numerical simulation of sea wave characteristics and operation downtimes of offshore structures is presented. The simulation was based on available wind data and seawater temperature recorded by an oceanography buoy installed in the Caspian Sea. Wave characteristics were simulated for deepwater parts of the Caspian Sea by applying the Bretschneider spectrum and equations using following recorded data: wind velocity, wind duration, fetch length, and water/air temperature differences. Since recorded wave data were only available for a one-year period, they were solely used for validation of the simulation results with recorded data but for not the simulation itself. Some practically established thresholds for wave velocity, wave period, and wind velocity were considered as constrains, limiting the operation of offshore installations. The numerical simulation model revealed that it is possible to operate offshore installations for 250 days per year in the southern parts of the Caspian Sea. A worst-case scenario showed that the maximum waiting time for restarting the offshore installations is 17 days. Considering the swell parameter, it was concluded that the annual downtime period of offshore installation operations in southern parts of the Caspian Sea is about one third of a year and the maximum waiting time for this operation is about two third of a month.

It appears that the past, present and future are created via information. This paper will demonstrate that all history was created via data. Data that has been saved and is accessible. Thus allowing us to recreate any event in history. This implies that the future can not exist without first having the information and data needed to create it. The present time exists only as the creation period for this information. Time is no more than data created by the wave collapse and in this same process holographed into what we think of as time and reality.

La modelación de los fenómenos físicos es una tarea muy compleja y hasta las mejores representaciones son sólo simplificaciones de la realidad. En el caso de los modelos numéricos, la veracidad de los resultados depende de las hipótesis propias de las ecuaciones que resuelven y de la calidad de los datos de entrada. Una práctica para incrementar significativamente la precisión de los resultados es la integración de modelos combinados o híbridos que permiten subsanar las deficiencias mediante una interacción conjunta. En este trabajo se presenta un modelo híbrido compuesto por un modelo de tercera generación (WAM), que estima el campo de oleaje en aguas profundas como función de datos de viento, y otro, de segunda generación (HURAC), que a partir de datos ciclónicos calcula los campos de viento, oleaje y presión atmosférica. Este segundo modelo se presenta en una versión actualizada, en la que se ha mejorado la precisión, como lo muestra la validación que aquí mismo se expone, y se ha optimizado su ejecución. Los resultados del modelo híbrido se comparan con las mediciones de siete boyas oceanográficas que registraron los efectos de 13 huracanes en el Golfo de México y el Caribe mexicano durante el año 2005. El incremento en la precisión de los resultados con respecto a la modelación utilizando únicamente el WAM o el HURAC, convierte al modelo híbrido en una fuente confiable de información del clima marítimo en aguas profundas tanto en condiciones medias como durante la ocurrencia de fenómenos extraordinarios.

Numerical technique for studying surface waves appearing under the motion of a submarine land-
slide is discussed. This technique is based on the application of the model of a quasi-deformable landslide
and two shallow water models, namely, the classic (dispersion free) one and the completely nonlinear dis-
persivemodel of the second hydrodynamic approximation. Numerical simulation of surface waves generated
by a large model landslide on the continental slope of the Black Sea near the Russian coast is performed.
It is shown that the dispersion has a signicant impact on the picture of propagation of tsunami waves on
suciently long paths.

Sedimentation is a critical threat to coral reefs worldwide. Major land use alteration at steep, highly erodible semi-arid islands accelerates the potential of soil erosion, runoff, and sedimentation stress to nearshore coral reefs during extreme rainfall events. The goal of this study was to assess spatio-temporal variation of sedimentation dynamics across
nearshore coral reefs as a function of land use patterns, weather and oceanographic dynamics, to identify marine ecosystem conservation strategies. Sediment was collected at a distance gradient from shore at Bahia Tamarindo (BTA) and Punta Soldado (PSO) coral reefs at Culebra Island, Puerto Rico. Sediment texture and composition were analyzed by dry sieving and loss-on-ignition techniques, and were contrasted with
environmental variables for the research period (February 2014 to April 2015). Rainfall and oceanographic data were analyzed to address their potential role on affecting sediment distribution with BEST BIO-ENV, RELATE correlation, and linear regression analysis. A significant difference in sedimentation rate was observed by time and distance from
shore (PERMANOVA, p < 0.0100), mostly attributed to higher sediment exposure at reef zones closer to shore due to strong relationships with coastal runoff. Sedimentation rate positively correlated with strong rainfall events (Rho = 0.301, p = 0.0400) associated with storms and rainfall intensity exceeding 15 mm/h. At BTA, sediment deposited were mostly composed of sand, suggesting a potential influence of resuspension produced by waves and swells. In contrast, PSO sediments were mostly composed of silt-clay and terrigenous material, mainly attributed to a deforestation event that occurred at adjacent steep sub-watershed during the study period. Spatial and temporal variation of sedimentation pulses and terrigenous sediment input implies that coral reefs exposure to sediment stress is determined by local land use patterns, weather, and oceanographic dynamics. Comprehensive understanding of sediment dynamics and coastal ecosystem interconnectivity is fundamental to implement integrated and adaptive
management strategies aimed to promote sustainable development at watershed and island wide-scale to fully mitigate terrigenous sediment impact to marine ecosystems. Furthermore, decision-making processes and policy needs to address sedimentation stress in the context of future climate to reduce land-based threats and strengthen coral reef resilience.

The vast tidal and wave energy resources represent a potential to use marine energy systems to supply part of the global
energy demand. However, there are many advances required to develop economic and reliable marine energy systems,
which some of these advances can be achieved by using the existing knowledge and experience from offshore and wind
energy industry. This research presents a novel marine energy system that integrates the concept of a vertical and horizon-
tal axis wind turbines by combining a Darrieus and Wells type rotor. However, many other different concepts have been
proposed, but models that account for hydrodynamic, structure and control are needed to determine their technical and eco-
nomical feasibility. With the use of the double-multiple streamtube theory, a hydrodynamic model is developed to predict
the performance and the loads on the turbine blades coupled with a finite element model to compute strains and stresses.
To validate the model, we used strain data from field measurement of the demo prototype. The validated model was used
to compute extreme stresses and calculate the fatigue life. The model gives reliable estimates of stresses and fatigue life.
With this result, the design analysis of the turbine blades can be optimized for any site condition and expected life time.

1] Realistic lunar tides of the Great Bay Estuarine System have been simulated using a fixed boundary finite element numerical model as described by . It is a two-dimensional, nonlinear, time-stepping model with a groundwater component coupled to a kinematic force balance to facilitate the realistic drainage and filling of elements during ebb and flood, respectively. The numerical model reproduces the observed M 2 tides as described by , and it successfully captures qualitatively correct residual currents and transports, realistic massconserving flooding and dewatering of the tidal flats, and current asymmetry between flood and ebb. The simulation results were sensitive to local bathymetry and the implemented friction law. The accuracy of the model is demonstrated by comparison with the 1975 Great Bay study in terms of tidal elevations at 14 tidal stations and 4 cross-sectionally averaged current measurements in the estuary. Quantitatively, the model results show good agreement with observations, displaying correlation coefficients of !0.96 in surface elevation and !0.95 in averaged current, with average RMS errors of 0.12 m and 0.26 m s À1 , respectively. In addition, tidal flat hydrodynamics, characteristic distributions of residual current, sediment bed load transport, and influence of topography on the overall circulation in the region are also discussed.

We start by a review of the chronology of mathematical results on the Dirichlet-to-Neumann map which paved the way towards the physics of transformational acoustics. We then rederive the expression for the (anisotropic) density and bulk modulus appearing in the pressure wave equation written in the transformed coordinates. A spherical acoustic cloak consisting of an alternation of homogeneous isotropic concentric layers is further proposed based on the effective medium theory. This cloak is characterised by a low reflection and good efficiency over a large bandwidth for both near and far fields, which approximates the ideal cloak with a inhomogeneous and anisotropic distribution of material parameters. The latter suffers from singular material parameters on its inner surface. This singularity depends upon the sharpness of corners, if the cloak has an irregular boundary, e.g. a polyhedron cloak becomes more and more singular when the number of vertices increases if it is star shaped. We thus analyse the acoustic response of a non-singular spherical cloak designed by blowing up a small ball instead of a point, as proposed in [Kohn, Shen, Vogelius, Weinstein, Inverse Problems 24, 015016, 2008]. The multilayered approximation of this cloak requires less extreme densities (especially for the lowest bound). Finally, we investigate another type of non-singular cloaks, known as invisibility carpets [Li and Pendry, Phys. Rev. Lett. 101, 203901, 2008], which mimic the reflection by a flat ground.

Studi mengenai gelombang permukaan (surface wave) telah banyak dilakukan baik secara eksperimen, teoritis maupun komputasi. Perkembangan teknologi komputer membuat komputasi dinamika fluida komputasi menjadi lebih cepat dan efisien salah teknologi untuk mempercepat komputasi general purpose of computing Graphics processor units(GPGPU). Pada artikel ini komputasi numerik large-deformation surface wave dilakukan dengan Graphics processor units (GPUs). Simulasi numerik large-deformation surface wave menggunakan SPH dalam 2D dan 3D. Untuk mendapatkan efek dari perubahan kedalaman secara simultan digunakan box pada numerical wave tank (NWT) fenomena ini dikenal sebagai"bank effect". Tujuan dari studi ini adalah untuk mereproduksi fenomena fisik dari pemodelan gelombang reguler maupun gelombang nonlinear dengan menggunakan obstacle box untuk mereproduksi fenomena large-deformation surface wave. Manfaat dari studi ini adalah fenomena large-deformation surface wave dapat direproduksi dengan SPH serta aplikasi SPH untuk permasalahan yang lebih kompleks dalam bidang teknik kelautan. Hasil dari studi ini menunjukan bahwa simulasi numerik SPH untuk large-deformation surface wave 2D dan 3D dapat direproduksi oleh SPH. SPH memiliki akurasi yang cukup tinggi baik untuk elevasi gelombang reguler maupun nonlinear.

The paper presents a decision support tool being developed to provide reliable forecasts on sea states prevailing at selected ports worldwide. The application will support approaching procedures of vessels to ports. It is based on cooperating , hydrodynamic models that derive data from global scale, open sea forecasts. The implementation of the project includes development and application of a hydrodynamic circulation model, a spectral wave propagation model and a phase-resolving wave model for port basins; model integration; and materialising a cloud-based forecast platform that will provide wind, wave, sea level and current data for a 3-day forecast every 3 hours. The laboratories of Harbour Works (NTUA) and Maritime Engineering (AUTh) will offer the research background while the third partner MarineTraffic will implement the on-line forecast platform for the end-users. The results of this applied research will lead to innovative products that will address significant needs such as increase of navigation safety at ports, facilitation of port pilotage operations, and improved port layouts.

Overtopping hazard at the beach of Gâvres (South Britanny)
The consulting firms, DHI and GEOS, were commissioned by the DDE of the Morbihan to characterize overtopping hazard at the beach of Gâvres (South Britanny) in order to map the Coastal Flooding Hazard by wave overtopping.
The main objectives of the study were: to provide an informative map of the natural phenomena on the study area, to establish a methodology and calibrate it using an historical event, and to model a 100 year event to characterize the
hazard.
The morphological evolution of the site has been described taking into account the effects related to natural and anthropogenic processes. A chronology of storms and damages has been established to determine the historical event for calibration.
A crossed statistical analysis of the offshore swell conditions and storm surge level has helped to estimate the Metocean conditions which characterize a 100 year event. A combination of a 7 m wave offshore with a marine level of +6.83 m
CM (French reference) has been identified as the most damaging for the site. The water level takes into account the effect of the tide, storm surge, the secular rise of the average level and subsidence.
The hazard maps have been established using the computation of the discharge overtopping structure, during the simulation of the 100 year event.

Forecast of wave agitation inside port basins and consequent downtime of berth positions are of utmost importance to make a port "smarter" by efficiently managing its infrastructure. Within Accu-Waves project (http://accuwaves.eu), a decision-making tool is being developed to provide forecast data on prevailing sea states in the vicinity of port entrances and inside harbour basins. The said tool will be based on cooperating hydrodynamic models that derive data from global scale, open sea forecasts. The implementation of the project includes development and application of a hydrodynamic circulation model, a spectral wave propagation model and a phase-resolving wave model for port basins. The latter is based on the hyperbolic mild-slope (HMS) equations, capable of simulating wave propagation and reflection. In order to achieve higher levels of simulation accuracy in the vicinity of waterfront structures, we need to robustly model the reflection of incipient waves from such structures (e.g., quay walls). In the present paper, this need is met through the incorporation of an additional, casespecific eddy viscosity coefficient to the governing mildslope equations (of the phase-resolving wave model). This coefficient accounts for the energy dissipation on port structures' fronts and its value is decided based on the corresponding reflection coefficient. A basic set of incident wave scenarios are simulated, required in investigating the numerics of reflection by the corresponding eddy viscosity coefficients in the wave model. Our pilot investigation refers to numerical experiments for several cases of waves approaching an either fully or partially reflective vertical quay wall. The proposed methodology could enhance similar HMS models; its results should be valuable for port operators.

The demand of information on extreme waves event, in particular site, has been increasing lately. The ocean waves condition have a very big influence on fisherman activity. Therefore, the maritime meteorological information such as wave height is very important for all human activities in the ocean and shore because,nearly 70% of Indonesian region is ocean. Unfortunately, both wave observation and wave forecast on the waters of Indonesia are very rare. Wavewatch III (WW3) model as the next generation of modeling wave model (WaM) and windwave could be used as an alternative solution to provide the information of wave. Here, WW3 model simulation used surface wind speed and wind direction data (10 meter) as initial data model in generating waves, which were extracted from the data of Final Analysis (FNL) model. The model also used bathymetry data as initial data model that should be arranged first to the same resolution as the FNL model's data. Resolution adjustment was done by resampling procedure that combined interpolation and aggregation to adjust the resolution. Thus, the data was then ready to be proceeded with the model of WW3. To examine the skills of the model, the output of the model was verified using significant wave height and wind speed data that were observed by satellite altimetry Jason 2. The WW3 model could capture wave high event. Results from the verification of WW3 model againts remote sensing data showed that Wavewatch Model III was good in simulating the significant wave height in southern coast of East Java with a given correlation value of 0.81 and RMSE values of 0.13 on the Conservation, using data from satellite altimetry Jason 2. However, the significant wave height tend to be over estimated.

The French research EMACOP project aims at characterising wave power nearby onshore structures. This paper presents the application of the non-hydrostatic wave-flow model SWASH to wave propagation and transformation on two hot spots in Brittany. The numerical simulations were performed for dominant wave conditions and three tide levels. The results of wave simulations allow us to characterise wave energy resources and define Wave Energy Converters (WEC)'s promising positions on both sites.
Keywords: Wave power, Resources, Numerical model, SWASH, Brittany, EMACOP.

Résumé :
Un des objectifs du projet de recherche EMACOP (Energies MArines, COtières et Portuaires) est de caractériser le potentiel houlomoteur près des structures portuaires et côtières, comme les digues et jetées. L'article présente l'application d'un modèle non-hydrostatique de propagation et de transformation des vagues en proche côtier SWASH pour deux sites exposés de Bretagne. Les simulations numériques sont effectuées avec SWASH pour les conditions de houle dominante et trois niveaux de marée. Les résultats présentés ici permettent de caractériser le potentiel houlomoteur et de définir les zones énergétiques propices à l'installation de systèmes de récupération sur les deux sites. Abstract: The French research EMACOP project aims at characterising wave power nearby onshore structures. This paper presents the application of the non-hydrostatic wave-flow model SWASH to wave propagation and transformation on two hot spots in Brittany. The numerical simulations were performed for dominant wave conditions and three tide levels. The results of wave simulations allow us to characterise wave energy resources and define Wave Energy Converters (WEC)'s promising positions on both sites.
Mots-clés : Potentiel houlomoteur, Modèle numérique, SWASH, Bretagne, EMACOP.

By simulating the dynamics of a bidimensional array of springs and masses, the propagation of conveniently generated waves is visualized. The simulation is exclusively based on Newton's second law and was made to provide insight into the physics of wave propagation. By controlling parameters such as the magnitude of the mass and the elastic constant of the mesh elements, it was possible to change the properties of the medium in order to observe the characteristic phenomena of wave mechanics, such as diffraction and interference. Finally, several examples of waves propagating in media with different configurations are presented, including the application of the simulation to the study of frequency response of a complex structure.

On 25 October 2010, a large earthquake occurred off the coast of the Mentawai islands in Indonesia, generating a tsunami that caused damage to the coastal area of North Pagai, South Pagai and Sipora islands. Field surveys were conducted soon after the event by several international survey teams, including the authors'. These surveys clarified the tsunami height distribution, the damage that took place and residents' awareness of tsunamis in the affected islands. Heights of over 5 m were recorded on the coastal area of the Indian Ocean side of North and South Pagai islands and the south part of Sipora island. In some villages, it was difficult to evacuate immediately after the earthquake because of the lack of routes to higher ground or the presence of rivers. Residents in some villages had taken part in tsunami drills or education; however not all villages shared awareness of tsunami threats. In the present paper, based on the results of these field surveys, the vulnerability of these islands with regards to future tsunami threats was analyzed. Three important aspects of this tsunami disaster, namely the geographic disadvantage of the islands, the resilience of buildings and other infrastructure, and people's awareness of tsunamis, are discussed in detail and corresponding tsunami mitigation strategies are explained.

Dans le cadre du projet national de recherche EMACOP (Energies MArines COtières et Portuaires), une méthode de calcul analytique a été employée pour propager la houle du large à la côte (GODA, 2000), à partir de l'analyse statistique de données de houle de l'atlas numérique ANEMOC (BENOIT et al., 2008). Elle a permis de caractériser le potentiel houlomoteur de 22 sites côtiers et portuaires des façades maritimes de la Manche et de l'Atlantique. La classification est établie à partir de l'analyse des résultats d'étude présentés dans le tableau récapitulatif et les fiches de sites. L'exemple de Saint-Guénolé est ici repris. Rappelons que les critères de bathymétrie, de puissances de houle annuelle et hivernale et de longueur de digue pouvant être équipée d'un système houlomoteur, ont été particulièrement examinés. L'évaluation a permis de retenir 9 sites de fort potentiel sur les façades Manche et Atlantique, avec des niveaux de puissance de houle les plus forts de 20 à 25 kW/m sur les sites de la pointe Bretagne et du Pays Basque.

Wave loads are critical factor for the design and safe operation of offshore structures.
The accurate determination of these loads is essential to ensure the structural
reliability and operational efficiency of such platforms at sea. This study develops
analytical expressions for calculating wave loadings that affect the support of various
Condeep-type offshore structures. In this regard, wave load calculations for the
Draugen Monopile Condeep platform, previously constructed in Norway, were
analyzed in the context of a case study. The results of this assessment provide useful
information regarding the characteristics of wave loads and their relevance to the
overall structural analysis. Furthermore, the investigation also covers
recommendations for design and safety improvements that consider the calculated
wave loads and the assessment of the structural reliability. Study is expected to
contribute to the knowledge base surrounding offshore engineering practices and
improve resilience and functionality against dynamic wave forces.

An updated version of a 2-DH post-Boussinesq wave model is introduced. The model is wavenumber free and as far as the linear dispersion relation is concerned, the approach is exact. It is implemented for the wave propagation and transformation due to shoaling, refraction, diffraction, bottom friction, wave breaking, wave-structure interaction, reflection, wave-current interaction, etc. in nearshore zones and specifically inside ports and in the vicinity of coastal structures. Thorough validation of the model is attempted by comparisons with output from classic laboratory-scale wave flume experiments as well as analytical solutions. Physical cases of both regular and irregular wave fields are numerically reproduced with acceptable accuracy. Results concerning a case study in a characteristic Greek port setup are also presented and seem encouraging for realistic scale simulations.

An approach to the computer simulation of a tsunami runup on the coast is presented,
based on nested grids and the largeparticle method. The computational algorithms are based on the
classical equations of shallowwater theory. The main elements of the developed computational tech
nology are described and the results are given of the verification and validation of numerical algo
rithms, as well as the mathematical model and of one and twodimensional test problems. The
capabilities of the algorithms developed by the authors are demonstrated for the calculation of the
defining parameters of the tsunami runup on the coast in the vicinity of the town of SeveroKurilsk
(November 5, 1952).

For a fissile medium, originally consisting of uranium-238, the investigation of fulfillment of the wave burning criterion in a wide range of neutron energies is conducted for the first time, and a possibility of wave nuclear burning not only in the region of fast neutrons, but also for cold, epithermal and resonance ones is discovered for the first time.
For the first time the results of the investigation of the Feoktistov criterion fulfillment for a fissile medium, originally consisting of uranium-238 dioxide with enrichments 4.38%, 2.00%, 1.00%, 0.71% and 0.50% with respect to uranium-235, in the region of neutron energies 0.015-10.0eV are presented. These results indicate a possibility of ultraslow wave neutron-nuclear burning mode realization in the uranium-plutonium media, originally (before the wave initiation by external neutron source) having enrichments with respect to uranium-235, corresponding to the subcritical state, in the regions of cold, thermal, epithermal and resonance neutrons.
In order to validate the conclusions, based on the slow wave neutron-nuclear burning criterion fulfillment depending on the neutron energy, the numerical modeling of ultraslow wave neutron-nuclear burning of a natural uranium in the epithermal region of neutron energies (0.1-7.0eV) was conducted for the first time. The presented simulated results indicate the realization of the ultraslow wave neutron-nuclear burning of the natural uranium for the epithermal neutrons.

Urban train infrastructures are very important for reliable urban mobility. This paper proposes a three-dimensional modeling of mechanized drilling corridors. Drilling in urban areas is always a risky and complex project. One of the most important issues during the construction of subway tunnels is the investigation of the impact of drilling steps on the ground subsidence and impact on existing structures. For this purpose, different types of mechanized drilling methods are often used, resulting in a considerable reduction in the displacements caused by tunnel drilling. In this study, part of the route of an urban train tunnel, that passes under a traffic interchange, is examined. The shear strength capacity of the slab pile was calculated, using the relevant equations, and then, the modeling of the soil mass was performed, using the PLAXIS 3D finite element program. The proposed depth of the tunnel construction, by the consulting company, is 18 meters. Due to drilling problems, depth of 14 meters has been suggested as an alternative. Analysis of both the depths of 14 and 18 meters, showed that the displacements at both depths, were approximately the same. However, the impact of the tunnel, on the capacity of the piles' tip, at a depth of 18 meters, is greater than at the depth of 14 meters. Thus, the suggested optimum depth is 14 meters, which is more suitable, than the initial suggested depth of 18 meters.

The deltaic lobe of Indian Sundarbans (IS) is highly vulnerable to natural disasters like cyclones that primarily occur during premonsoon and monsoon seasons. These natural disasters take the lives of people and damage properties of the island dwellers. The mangroves act as a buffer against these vulnerabilities and play important role in the domain of disaster management. The SWAN (Simulating WAves Nearshore) model is simulated based on the real time data of mangrove vegetation collected from the western and central IS having contrasting salinity pattern to study the wave attenuation characteristics. The percentage of wave attenuation is much higher in the hyposaline stations of western IS compared to the hypersaline central sector. The cumulative effect of vegetation and mud is established in this work on the wave attenuation potential and thereby prevent the island villages from natural disaster. Our Heritage Application of numerical modeling to evaluate the role of mangroves in wave attenuation: A first order analysis in the domain of disaster management

The French national EMACOP project (Énergies Marines Côtières et Portuaires) aims at characterising wave power nearby on-shore structures such as breakwater or jetty. This paper presents the application of the open source nonhydrostatic wave-flow model SWASH to wave propagation and transformation on two hot spots in Brittany (France). The numerical simulations were performed with the SWASH model in two-dimensional mode for dominant incident wave conditions and three tide levels. The results of wave simulations presented here allows us to characterise wave energy resources and define WEC's promising positions on both sites.

The tsunami hazard for the coast of the Sea of Okhotsk requires a careful analysis, because this sea
will be a zone of responsibility for the Tsunami Warning Service for the Far East coast of Russia. While it is
not subject to such hazards on the part of seismogenic zones that can produce dangerous tsunamis, neverthe
less the Sea of Okhotsk is open for penetration of tsunamis that can be produced by sources in other tsunami
generating zones of the Kuril–Kamchatka region, as well as those of the entire Pacific Ocean. The tsunami
hazard for the coast of the Sea of Okhotsk is examined here on the basis of historical observations and the
results of numerical simulation for tsunami propagation from hypothetical rupture zones of near and distant
earthquakes. It is shown that the real tsunami hazard can only emanate from those regional earthquakes with
magnitudes 8.5 or greater that occur in the Kuril–Kamchatka seismogenic zone. Among the remote tsunami
generating zones in the Pacific, the most dangerous locations are the rupture zones of megaearthquakes of
the class M9 that come from the South America zone and from Papua–New Guinea. These can produce
water waves with amplitudes as great as 5 m along the entire coast of the Sea of Okhotsk.

The sine-Gordon equation turn up in several problems in science and engineering. Although it is integrable, in practical applications, its numerical solution is powerful and versatile. Four novel implicit finite difference methods based on (q , s) Padé approximations with (q + s) th order in space have been developed and analyzed for this equation; all share the same treatment for the nonlinearity and integration in time. Concretely, (0,4), (2,2), (2,4), and (4,4) Padé methods; additionally, the energy conserving, Strauss-Vázquez scheme has been considered in a (0,2) Padé implementation. These methods have been compared among them for both the kink-antikink and breather solutions in terms of global error, computational cost and energy conservation. The (0,4) and (2,4) Padé methods are the most cost-effective ones for small and large global error, respectively. Our results indicate that spatial order of accuracy is more relevant to effectiveness of a method than energy conservation even in very long time integrations.

A numerical model is employed here to study seiche oscillations of layered or stratified fluids in a closed rectangular tank under various initial inclination angles of the free surface and interfacial layers to the normal water table as seiche setup conditions. Laboratory experiments were also conducted for layered sloshing in a rectangular tank. The numerical model was validated against the experimental data and the available numerical results. The effect of the setup angle on the maximum interfacial and free surface wave height time series were then studied in relation to their corresponding dominant frequency response. The effects of internal structures on the rate of wave decay were analyzed for internal and free surface waves with key findings being reported.

A method for numerical modelling of tsunami wave runup on a coast is presented. The
method is based on applying a combination of both 1D and 2D approximations of the shallow
water model. First, the two-dimensional model with non-reflective boundary condition on a
coast is used for computation of wave propagation from a source to a coast. Then the flow
parameters on some isobathic line, which are obtained from this computation, are used as the
boundary conditions for one-dimensional modelling of runup along different cross-sections,
drawn from this isobathic line to a chosen isobathic line on the dry land. The procedure
is described for recovering the inundation boundary using the solution of one-dimensional
problems. The comparison of three algorithms for computation of waterfront point movement
is presented and the results of the numerical modelling of the tsunami in Japan in 2011 are
provided.

A two-way coupled long wave to Reynolds-averaged Navier-Stokes (RANS) wave model named 2CLOWNS is introduced in this study and its numerical procedure is described in detail. The model is applied to solitary wave transformation and breaking on plane beaches with slopes 1/100, 1/60, 1/35 and 1/20. Two-way coupling was verified for test cases of pure solitary wave reflection on a flat bed, and wave transformation on slopes including rundown. The algorithm becomes sufficiently robust when a no gradient boundary condition on the vertical velocities is applied, the local wave height and slope are sufficiently small, and the coupling depths are sufficiently large. Suggested limits to the local wave height and slope are outlined. Characteristics of shoaling prior to breaking are analysed in detail for the long wave model. Optimal depths for coupling to the RANS model are found that approximately correspond to the transition from gradual shoaling to rapid shoaling. An expression that estimates this location is presented based on a nondimensional slope parameter. Overall, 2CLOWNS is shown to approximate shoaling and breaking characteristics in comparison with theory, physical experiments and other numerical analyses. The post-breaking behaviour and wave shape approximate theoretical descriptions and experimental observations including the touchdown of the plunging jet and resulting splashup. Velocity profiles are shown to be considerably different to ones based on depth-integrated models just prior to wave breaking and thereafter. 2CLOWNS allows for more reliable simulations when computing wave propagation from far offshore towards the coast in reduced computational time compared with full RANS simulations under the appropriate conditions outlined in this study.

2014): Development and validation of a computational model of the knee joint for the evaluation of surgical treatments for osteoarthritis, Computer Methods in Biomechanics and Biomedical Engineering, A three-dimensional (3D) knee joint computational model was developed and validated to predict knee joint contact forces and pressures for different degrees of malalignment. A 3D computational knee model was created from high-resolution radiological images to emulate passive sagittal rotation (full-extension to 658-flexion) and weight acceptance. A cadaveric knee mounted on a six-degree-of-freedom robot was subjected to matching boundary and loading conditions. A ligamenttuning process minimised kinematic differences between the robotically loaded cadaver specimen and the finite element (FE) model. The model was validated by measured intra-articular force and pressure measurements. Percent full scale error between FE-predicted and in vitro-measured values in the medial and lateral compartments were 6.67% and 5.94%, respectively, for normalised peak pressure values, and 7.56% and 4.48%, respectively, for normalised force values. The knee model can accurately predict normalised intra-articular pressure and forces for different loading conditions and could be further developed for subject-specific surgical planning.

The Rho GTPases pattern the cell cortex in a variety of fundamental cell-morphogenetic processes, including division, wound repair, and locomotion. It has recently become apparent that this patterning arises from the ability of the Rho GTPases to self-organize into static and migrating spots, contractile pulses, and propagating waves in cells from yeasts to mammals.1 These self-organizing Rho GTPase patterns have been explained by a variety of theoretical models that require multiple interacting positive and negative feedback loops. However, it is often difficult, if not impossible, to discriminate between different models simply because the available experimental data do not simultaneously capture the dynamics of multiple molecular concentrations and biomechanical variables at fine spatial and temporal resolution. Specifically, most studies typically provide either the total Rho GTPase signal or the Rho GTPase activity, as reported by various sensors, but not both. Therefore, it remains largely unknown how membrane accumulation of Rho GTPases (i.e., Rho membrane enrichment) is related to Rho activity. Here, we dissect the dynamics of RhoA by simultaneously imaging both total RhoA and active RhoA in propagating waves of Rho activity and F-actin polymerization.2,3,4,5 We find that within nascent waves, accumulation of active RhoA precedes that of total RhoA, and we exploit this finding to distinguish between two popular theoretical models previously used to explain propagating cortical Rho waves.

This work presents a validation of wave parameters from the new sixty years Downscaled Ocean Waves (DOW) reanalysis database. This study compares quantiles of the Gumbel distribution of Hs (significant wave height) and Tp (peak period) from simulated data with an 11 months&#39; time series obtained from a buoy moored seaward on the Santa Catarina coast. Analysis by means of Gumbel distribution quantiles allows more weight to be given to the highest values of the time series, which are especially important in design projects. The statistical parameters used to verify the fit between the measured and the modeled data included: RMSE, BIAS, Scatter Index and Pearson Correlation Coefficient. Mean direction (θm) validation was conducted qualitatively. The database showed good fit of the mean conditions, especially Hs which was well reproduced by the wave model. Underestimation of Tp, related mainly to the low spatial and temporal resolution of wind data used to generate waves, highlights ...

Results of a numerical simulation of the action of distant tsunamis on the coast of the Russian Far
East are presented. It is shown that waves generated by focuses of the strongest M9 earthquakes in the region
of South Chilean coast, as well as in the region of Papua New Guinea and Solomon Islands, are most dan
gerous for this coast. Other tsunamigenic zones of the Pacific Ocean, by virtue of their geographical position,
orientation of focuses, and absence of pronounced channels (submarine ridges) along paths of tsunami prop
agation are not dangerous for it even at a limit magnitude of submarine subduction earthquakes. The simulation
results are compared with historical data about manifestations of distant tsunamis on the Russian Far East coast.

Local artificial boundary conditions (ABCs) for the numerical simulation of waves have been successfully used for decades (most notably, the boundary conditions due to Engquist & Majda, Bayliss, Gunzburger & Turkel, and Higdon). The basic idea behind these boundary conditions is that they cancel several leading terms in an expansion of the solution. The larger the number of terms canceled, the higher the order of the boundary condition and, in turn, the smaller the reflection error due to truncation of the original unbounded domain by an artificial outer boundary. In practice, however, the use of local ABCs has been limited to low orders (first and second), because higher order boundary conditions involve higher order derivatives of the solution, which may harm well-posedness and cause numerical instabilities. They are also difficult to implement especially in finite elements. A prominent exception is the development of local high order ABCs based on auxiliary variables. In the curr...

Un des objectifs du projet de recherche EMACOP (Energies MArines, COtières et Portuaires) est de caractériser le potentiel houlomoteur près des structures portuaires et côtières, comme les digues et jetées. L'article présente l'application d'un modèle nonhydrostatique de propagation et de transformation des vagues en proche côtier SWASH pour deux sites exposés de Bretagne. Les simulations numériques sont effectuées avec SWASH pour les conditions de houle dominante et trois niveaux de marée. Les résultats présentés ici permettent de caractériser le potentiel houlomoteur et de définir les zones énergétiques propices à l'installation de systèmes de récupération sur les deux sites.

Low-lying tropical islands are highly vulnerable to the effects of sea-level rise and climate change. Most pressing is the threat posed to their fresh water supplies by wave-induced flooding. This thesis attempts to generalize previous site-specific studies of flooding on coral atolls and apply it in a framework that can be used for early warning systems or long-term climate change impact studies. To do so, a large synthetic database of representative reef properties and hydrodynamics was developed using the numerical wave model XBeach, and then analyzed using a Bayesian probabilistic network. The resulting tool allows us to make real-time flood predictions based on offshore wave or sea level conditions, and the unique characteristics of a given island (e.g. topography). Narrow, smooth reefs with steep fore reef slopes are the most vulnerable to runup. Extreme flooding is associated with anomalously high, resonant low frequency waves, which are more likely to occur on narrow, smooth reefs subjected to extreme swell waves (large wave heights with long periods). These extreme swells are "blue sky" events which originate from distant storms. Thus, they may thus arrive without warning, since they are completely independent of local weather conditions. This bolsters the need for more effective prediction tools. Validation of the results presented in this study is limited by the small number of field observations against which the model can be compared. Thus, there is a need to develop a comprehensive database of reef morphology and hydrodynamics. Offshore wave conditions, water levels, and reef width are the most essential variables for predicting runup, so future research efforts should be directed towards collecting those data. This model can also be used to ask questions like, "which islands will be most severely impacted by climate change?", or "can we increase flood resilience for a given island by restoring its coral reefs?". Hence, there is also potential for its use in guiding decision-makers to allocate limited funding in the places where it will have the most impact.

Four novel implicit finite difference methods with (q + s)-th order in space based on (q, s)-Padé approximations have been analyzed and developed for the sine-Gordon equation. Specifically, (4,0)-, (2,2)-, (4,2)-, and (4,4)-Padé methods. All of them share the treatment for the nonlinearity and integration in time, specifically, the one that results in an energyconserving (2,0)-Padé scheme. The five methods have been developed with and without Richardson extrapolation in time. All the methods are linearly, unconditionally stable. A comparison among them for both the kink-antikink and breather solutions in terms of global error, computational cost and energy conservation is presented. Our results indicate that the (4,0)-and (4,4)-Padé methods without Richardson extrapolation are the most costeffective ones for small and large global error, respectively; and the (4,4)-Padé methods in all the cases when Richardson extrapolation is used.

I propose a definition for a "shocking coefficient" S intended to make determinations of the degree of waveform shocking, and comparisons thereof, more quantitative. This means we can avoid having to make ad hoc judgements on the basis of the visual comparison of wave profiles.