bluuebunny/crossref_metadata_2025 huggingface dataset:
DROP TEST OF PROTOTYPE CUBE AND CUBIPOD ARMOR UNITS
Authors: Corredor Antonio , Torres Rafael , Miñana Juan Vicente , Fernández Enrique , Menéndez Carlos Fermín , Santos Moisés , Gómez-Martín M. Esther , Medina Josep R.
Published: October 2012

The structural strength of concrete armor units (CAUs) is a key factor in the design and construction of armor layers for large mound breakwaters. This paper describes the prototype drop tests carried out to assess the structural strength of conventional cube and Cubipod CAUs. Low intensity overturning tests, high intensity free fall tests and extreme intense free fall tests were conducted to measure the structural integrity under impact loads of the Cubipod CAU
compared to the conventional cubic block. The casting systems and pressure clamps were specifically designed to manufacture and handle the 15-tonne conventional cube and 16-tonne Cubipod prototypes used for the drop tests.
Two reinforced-concrete platforms were used for overturning and free fall tests. The 16-tonne Cubipod prototypes withstand drops more than 50% higher than 15-tonne conventional cube prototypes of similar concrete strength. Two extreme free fall tests verified the robustness of Cubipod prototypes in accidental falls during construction. Both Cubipod and conventional cube CAUs have similar stacking and handling procedures as well as manufacturing cycle
time.
CAISSON BREAKWATER DESIGN FOR SLIDING
Authors: Hutchinson Steven , Young Martin , Macleod Alasdair
Published: October 2012

The offshore caisson breakwater at Costa Azul installed in 25m water depth is designed to withstand Pacific swell waves up to a PLS test case Hs 9.2m Tp 18.6s. Overall stability design is in accordance with the recommendations of PIANC WG 28. The critical failure mechanism is sliding, and the caisson base is cast with a deliberately roughened (serrated) profile to increase sliding resistance and optimize the caisson cross section. Site based testing at prototype scale was conducted to validate the coefficient of friction used for design between the caisson base and nominal 100mm single size granular bedding material. This testing confirms that the use of a suitably dimensioned serrated base profile allows the full internal angle of friction (with allowance for dilation) of the bedding material to develop at the base of the caisson, allowing the cross section design to be optimized.
QUAY DESIGN AND OPERATIONAL OCEANOGRAPHY. THE CASE OF BILBAO HARBOUR
Authors: Sánchez-Arcilla Agustín , Espino Manuel , Grifoll Manel , Mösso Cesar , Sierra Joan Pau , Mestres Marc , Spyropoulou Stella , Hernaez Mario , Ojanguren Alberto , G.-Sotillo Marcos , Alvarez-Fanjul Enrique
Published: October 2012

In this paper a harbour engineering application of an operational system to forecast circulation and transport fields is presented. It deals with the functional design of a quay in the Bilbao harbour (Bay of Biscay, North-Atlantic coast of Spain). The aim is to use physical oceanography "tools† to design the optimal quay alignment according to two criteria: i) Minimize the currents in order to guarantee the vessel maneuverability and quay operability for given safety levels and ii) Maximize the water renewal capacity of the harbour inner basins (beyond the studied quay) in order to reduce the risk of water quality degradation. The methodology and the results reveal a new procedure to enhance the harbour lay-out design from an environment point of view.
CONSTRUCTION OF TWO NEW BREAKWATERS AT OSTEND LEADING TO AN IMPROVED HARBOUR ACCESS
Authors: Verhaeghe Hadewych , Van Damme Luc , Goemaere Jan , De Rouck Julien , Van Alboom Wim
Published: October 2012

The need of an improved harbour access resulted into the design of two new breakwaters in Ostend. The construction of the new breakwaters fits within the Integrated Coastal and Maritime Plan for Ostend. This paper describes the history, the extensive studies, the architecture and the construction works of the breakwaters. Finally future developments are considered.
EXPERIMENTAL RESEARCH ON COEFFICIENT OF WAVE TRANSMISSION THROUGH IMMERSED VERTICAL BARRIER OF OPEN-TYPE BREAKWATER
Authors: Ju Liehong , Li Peng , Yang Ji hau
Published: October 2012

Extensive researches have been done for the interaction between open-type pile foundation structure and waves, including uplift force of wharf deck, horizontal force of structure and wave transmission behind breakwaters, among which wave transmission is mainly discussed in this paper. The wave transmission through a single immersed vertical barrier is analyzed by use of the physical model experiment; and an approximate formula to calculate the coefficient of wave transmission through a barrier is presented. Finally the wave damping effect of twin barriers is tested and analyzed.
STABILITY OF GIRDER BRIDGE AGAINST TSUNAMI FLUID FORCE
Authors: Araki Susumu , Ishino Kazuo , Deguchi Ichiro
Published: October 2012

The horizontal and vertical components of the fluid force and pressure acting on a girder bridge due to tsunami like a solitary wave are measured in a hydraulic experiment and their characteristics are discussed. The peak of the impact fluid force is estimated on the basis of the change in the added mass of the structure. The wave pressure acting on the seaward side of the girder of the bridge is also estimated. The critical force for the stability of the girder bridge is estimated as the strength of bolts used in the shoes against shear stress.
WAVE STRUCTURE INTERACTION: ROLE OF ENTRAPPED AIR ON WAVE IMPACT AND UPLIFT FORCES
Authors: Bozorgnia Mehrdad , Lee Jiin-Jen , Raichlen Frederic
Published: October 2012

In present paper, a numerical wave load model based on compressible two-phase Navier Stokes type equations is used to evaluate hydrodynamic forces exerted on I-10 bridge across Mobil Bay which was extensively damaged during Hurricane Katrina. The volume of fluid method (VOF) is used in the model to describe dynamic free surface which is capable of simulating complex discontinuous free surface associated with wave-deck interactions. Special emphasis was put on investigating the role of entrapped air on hydrodynamic forces exerted on bridge superstructure. Numerical simulation results indicate that air entrapment can significantly amplify uplift forces applied to the bridge superstructure. To mitigate hydrodynamic forces, effectiveness of airvents is investigated. It has been shown that airvents can significantly damp out wave energy and can effectively reduce uplift forces.
STABILITY CONSIDERATIONS AND CASE STUDIES OF SUBMERGED STRUCTURES CONSTRUCTED FROM LARGE, SAND FILLED, GEOTEXTILE CONTAINERS
Authors: Borrero Jose Carlos , Mead Shaw T , Moores Andrew
Published: October 2012

The use of large, sand filled geotextile containers for the construction of offshore structures is gaining acceptance as a cost effective method of submerged breakwater or reef construction. This method of construction is partuicularly well suited for multipurpose structures where the intent is to provide breakwater-like wave attenuation and shore protection while at the same time providing recreational amenities such as ecological enhancment or surfing. Because the materials and methods used in these structures is relatively new, design guidance is lacking. This paper discusses the general stability considerations for submerged structures constructed from sand filled geotextile containers (SFC's) and describes a method of assessing container stability through the use of numerical models and empirically derived stability formulae. The paper also describes lessons learned from case studies of four very differnt examples of this type of construction.
NEAR-SHORE FLOATING WAVE ENERGY CONVERTERS: APPLICATIONS FOR COASTAL PROTECTION
Authors: Ruol Piero , Zanuttigh Barbara , Martinelli Luca , Kofoed Peter , Frigaard Peter
Published: October 2012

Aim of this note is to analyse the possible application of a Wave Energy Converter (WEC) as a combined tool to protect the coast and harvest energy. Physical model tests are used to evaluate wave transmission past a near-shore floating WEC of the wave activated body type, named DEXA. Efficiency and transmission characteristics are approximated to functions of wave height, period and obliquity. Their order of magnitude are 20% and 80%, respectively. It is imagined that an array of DEXA is deployed in front of Marina di Ravenna beach (IT), a highly touristic site of the Adriatic Coast. Based on the CERC formula, long-shore sediment transport is evaluated in presence and in absence of this array of DEXAs. The sediment transport in this site is quite large and frequently changes directions during the year. The larger North directed contribution and the more persistent South directed one are similar in magnitude and almost compensate each other, with the latter only slightly prevailing. It is shown that the DEXA could be designed so that the effect on sediment transport becomes quite significant and the direction of the net transport can be reversed.
WAVE ENERGY CONVERSION USING A BLOW-JET SYSTEM
Authors: Mendoza-Baldwin Edgar , Silva-Casarín Rodolfo , Sánchez-Dirzo Rafael , Chávez-Cárdenas Xavier
Published: October 2012

This paper presents the results of exhaustive experimental work focused on evaluating the efficiency of two devices as wave energy converters and as coastal protection alternatives. The first device is a wave amplifier that by means of overtopping stores water in a reservoir where potential energy can be used to produce power. The second device, the Blow-Jet, is a novel proposal that gathers together the operation of a tapchan and a blowhole to generate an intermittent jet that can easily feed a turbine. Results show that for both devices there is a strong dependency on the wave climate but that there is a possibility of optimizing geometric designs. Transmission coefficient values obtained for the Blow-Jet point to a real chance for its use as a multi-purpose coastal structure.
GENERATING ELECTRICITY AT A BREAKWATER IN A MODERATE WAVE CLIMATE
Authors: Schoolderman Joris , Reedijk Bas , Vrijling Han , Molenaar Wilfred , Ten Oever Erik , Zijlema Marcel
Published: October 2012

A new concept for wave energy conversion is examined as a proof of concept for generating electricity in a moderate wave climate while being integrated in a caisson breakwater. Physical model testing is performed to analyse the preliminary efficiency of the device and to identify areas of improvement. The resulting device is calculated for two sample locations in order to gain an understanding of its feasibility. Recommendations are made for continued research and possible improvements of the design.
GEOTECHNICAL DESIGN OF BREAKWATERS IN OSTEND ON VERY SOFT SOIL
Authors: De Rouck Julien , Van Doorslaer Koen , Goemaere Jan , Verhaeghe Hadewych
Published: October 2012

Two new breakwaters are being constructed to protect the renewed harbour entrance in Ostend, Belgium. In this paper, both the hydraulic design and geotechnical design are discussed. For the hydraulic design, model tests have been carried out in a 2-D wave flume to optimise the cross section. Stability of the final breakwater, with special attention to the crest element and the armour unit HARO, and stability during the construction phases were tested. The geotechnical design, especially of the north-western breakwater, was an engineering challenge since it is located above a thick layer of very soft soil. A combination of building in stages (consolidation time) and providing a strong reinforcement (geotextile) solved this issue.
THE DEFORMATION ANALYSIS AND MESO OBSERVATION TESTS OF PILE SIDE FINE SAND UNDER LATERAL LOADING
Authors: Liu Wenbai , Deng Yibing , Guo Rong
Published: October 2012

The pile side soil deformation analysis and meso-observation were conducted for revealing the meso-mechanism of lateral bearing pile with practical significance. Lateral cyclic load tests were carried out on full model and semispatial mode single piles embedded in fine sand to study the behaviour of pile side soil. Through the digital photography and microscopic meso-observation images on the semispatial model test, digital photography for the deformation of soil analysis, and microscopic meso-observation images for the meso-structure analysis, carry out the works of soil meso-mechanical properties and its associated research, test method of macro and meso-analysis was proposed. Through non-marking points digital photogrammetry of deformation measurement system, the biggest shearing strain, volumetric strain and displacement vector distribution of pile the surrounding fine sand of the laterally loading on experiments of semispatial model was analysed, depends on this determination the shearing failure area and meso-observation point. The applied MiVnt image analysis system has processed the meso-observation images of soil structure, has sum up and analysed the change of meso-parameters, numbers of particles, total area of particles, voil ratio e, voil ratio increment , major axis mean of particles, minor axis mean of particles, eccentricity mean of particles, particle size, particle direction. This is an effective method of analysis, through deformation analysis and meso-structure analysis of soil structure on the semispatial model test, studing the macro-and meso-mechanical properties and its correlation.
COMPARISON OF GEOSYNTHETIC MATERIALS AS SUBSTRATES ON COASTAL STRUCTURES - GOLD COAST (AUSTRALIA) AND ARABIAN GULF
Authors: Corbett Bobbie , Jackson Leslie Angus , Evans Timothy , Restall Simon
Published: October 2012

Coastal structures should be designed to minimize the risks to beach users and avoid negative impacts on the marine environment. Past experience with sand-filled geotextile containers in the marine environment (i.e. submerged) shows that they provide a permeable substrate that supports a diverse range of marine growth which differs from that found on conventional "hard† structures. To quantify the potential benefits, comparative trials between different geosynthetics at different depths have been undertaken in both in the hot high salinity waters of the Arabian Gulf [UAE] and in the sub-tropical waters of the Pacific Ocean [Gold Coast, Australia]. Results indicated that high strength non-woven type geosynthetics are most suitable for structures which are intended to provide ecological / recreational benefits as they provide higher diversity and less hard growths which are not as user-friendly.
BREACHING OF SEA DIKES
Authors: Bernitt Laurits , Lynett Patrick
Published: October 2012

Risk Analysis of sea dikes is a fundamental tool for protection of human health and safety, private and public property and cultural heritage. The modern risk concept defines risk as the product of inundation probability times the consequences of inundation. The risk concept is a versatile tool for any matter, public, private or environmental endangered by storm surges. The hydraulic task in a sea dike risk analysis is the determination of the internal water level. The present breaching intensity model, is part of a connected complex of models for transforming an external surge to an internal inundation. The complex is calibrated on the New Orleans East Back Levee breaches blown by hurricane Katrina in 2005.
MODELLING WATER ENTRY OF A WEDGE BY MULTIPHASE SPH METHOD
Authors: Gong Kai , Wang Benlong , Liu Hua
Published: October 2012

The hydrodynamic problem of two-dimensional wedge entering water is studied based on SPH model. A non-reflection boundary treatment for SPH method is proposed to reduce the size of computational domain. The details of water entry and enclosing are simulated using two phase SPH model. Both the water flow around the cavity and wedge and air flow inside the cavity are predicted simultaneity. Good agreement is obtained comparing experimental data in terms of both the hydrodynamics force exerting on the wedge and geometry of the cavity and jet.
A FULLY NONLINEAR BOUSSINESQ MODEL FOR WATER WAVE PROPAGATION
Authors: Zhang Hong-sheng , Zhou Hua-wei , Hong Guang-wen , Yang Jian-min
Published: October 2012

A set of high-order fully nonlinear Boussinesq-type equations is derived from the Laplace equation and the nonlinear boundary conditions. The derived equations include the dissipation terms and fully satisfy the sea bed boundary condition. The equations with the linear dispersion accurate up to [2,2] padé approximation is qualitatively and quantitatively studied in details. A numerical model for wave propagation is developed with the use of iterative Crank-Nicolson scheme, and the two-dimensional fourth-order filter formula is also derived. With two test cases numerically simulated, the modeled results of the fully nonlinear version of the numerical model are compared to those of the weakly nonlinear version.
A NUMERICAL MODEL FOR WAVE PROPAGATION OVER MUDDY SLOPE
Authors: Niu Xiaojing , Yu Xiping
Published: October 2012

A numerical model for the interaction between waves and muddy seabed is developed, in which the motion of the movable mud and the motion of water are solved simultaneously. The governing equations for both water and the mud are the continuity equation and the equations of motion for incompressible fluids. Water is treated as a Newtonian fluid, while a visco-elastic-plastic model is used to describe the rheology of the mud. Both the interface between water and the mud and the free water surface are traced by the VOF (Volume of Fluid) method. The numerical method is based on the well-known SMAC method. The numerical model is applied to simulate wave propagation over a muddy slope, and the numerical results are in reasonable agreement with the experimental data. The present model is proved better performance than the traditional analytic model in case that topography change is not negligible.
WAVE TRANSFORMATION AND WAVE-DRIVEN CIRCULATION ON NATURAL REEFS UNDER EXTREME HURRICANE CONDITIONS
Authors: Marino-Tapia Ismael , Silva Rodolfo , Enriquez Cecilia , Mendoza-Baldwin Edgar , Escalante-Mancera Edgar , Ruiz-Rentería Francisco
Published: October 2012

The understanding of wave transformation and circulation on coral reef environments has profound implications for the preservation of the natural environment and also for the planning of mitigation measures which protect the coastline. Most of the Mexican Caribbean coast is fronted by reefs, and it is here where coastal development is being undertaken at an alarming rate, as tourist resorts expand and multiply. The transport and dispersion of larvae (fish and coral), nutrients, pollutants, heat, and sediments are dictated mainly by circulation processes which are, to a great extent, dominated by wave processes at fringing reefs. Wave transformation on coral reefs has received considerable attention, but the 2D effects of wave reflection and diffraction have not often been addressed despite the complex geometry and steep foreshores that characterize fringing reefs. In this contribution the effects of reflection and diffraction are explored by the application of a model that considers these two processes (WAPO/COCO) and another that does not (SWAN/DELFT3D), at Puerto Morelos on the Mexican Caribbean coast. Reanalysis data of 48 years of wave parameters show that waves of 2 m height can be considered as high energy storm conditions, which are generated mainly by passing hurricanes and to a lesser extent by northerly storms in winter. These are the conditions used to run the models using a range of wave periods (8, 10 and 12 seconds) and directions (SE, NE and NNE). The results show that the reflection-solving model is able to generate rhythmic patterns in the horizontal distribution of Hs that are not reproduced by the SWAN model. Furthermore, the patterns change considerably depending on wave period and direction. These differences are attributed to the effects of full diffraction and reflection processes. While both models perform well and reproduce previously reported circulation patterns, the differences in Hs horizontal distribution generated by the WAPO model have important implications for the circulation around the reef crests. For instance, vorticity is increased and in many occasions a different pattern from that suggested by SWAN occurs, such as a clear southward longshore current along the reef crest under northerly wave forcing. Although the circulation was calculated in both models by the same method (radiation stress gradients), the version of COCO which was used generates smaller set-up inside the reef lagoon and therefore the circulation in this region and at the outlets is underestimated. Although it is necessary to corroborate the model results with measurements of the 2D wave height patterns and circulation, the magnitude of the currents suggested by the reflection-solving model are strong enough to persist even under the presence of stronger flows inside the lagoon and at the inlets due to wave set-up gradients.
NUMERICAL MODELING OF OBSERVED HURRICANE WAVES
Authors: Chen Qin Jim , Hu Kelin , Kennedy Andrew
Published: October 2012

Extensive field measurements of wind waves in deep and shallow waters during Hurricane Gustav (2008) in the Gulf of Mexico have been simulated by the spectral wave prediction model, SWAN. First, a parametric asymmetric hurricane wind model with three major improvements is used to generate hurricane wind fields for the wave model. The changes of water level near the coast are taken into account by using a storm surge model. Forced by the verified hurricane winds and hindcasted water levels, the wave model performs fairly well in comparison to the observed wave heights and periods in both deep and shallow waters except a few locations with complex bathymetry and landscape. In addition to the hurricane wind field that controls the accuracy of wave modeling in deep water, wave-surge interaction plays an important role in the wave growth and transformation in shallow water. Wave spectral comparisons show that the white-capping formulation of Westhuysen et al. (2007) generally outperforms the default formulation of Komen et al. (1984) in SWAN under hurricane conditions. The model result indicates that the asymmetry of hurricane winds and the hurricane translation result in the maximum wind waves occurring on the right side of the hurricane track and propagating in the direction parallel to the hurricane translation direction, consistent with field observations.
HURRICANE IKE (2008) NEARSHORE WAVES: SIMULATIONS AND MEASUREMENTS
Authors: Bender Christopher J. , Smith Jane M. , Kennedy Andrew
Published: October 2012

Hurricane Ike (2008) caused extensive damage and many deaths across portions of the Caribbean and along the coasts of Texas and Louisiana. After reaching peak intensity over the open waters of the Atlantic Ocean, Hurricane Ike, with its associated storm surge, then caused extensive damage across parts of the northwestern Gulf Coast when it made landfall in the late hours of September 12th along the upper Texas coast at the upper end of Category 2 intensity. An extensive instrumentation effort allowed the collection of both nearshore and inland wave and water level data as Hurricane Ike passed by the Louisiana and Texas coasts. This paper presents the results of a validation effort for the STWAVE model and the bottom friction coefficients applied in the model with comparisons to the Hurricane Ike measured wave data. STWAVE model results indicate good agreement with the measured nearshore wave data for an open water Manning 'n' bottom friction coefficient equal to 0.03 s/m0.33. STWAVE model results indicate good agreement with the measured inshore wave data with Manning 'n' bottom friction coefficients equal to values derived from land classification data and applied in the ADCIRC model.
DEVELOPMENT OF AN INVERSE ESTIMATION METHOD OF SEA SURFACE DRAG COEFFICIENT UNDER STRONG WIND CONDITIONS
Authors: Yokota Masaki , Hashimoto Noriaki , Kawaguchi Koji , Kawai Hiroyasu
Published: October 2012

For the purpose of clarifying the mechanism of energy transfer from high wind to waves, the ADWAM, a wave prediction model incorporating the data assimilation method, was modified to deduce the sea surface drag coefficients as its control variables. Validity of the model was verified through the identical twin experiment in deep sea conditions. Also, the behavior of the deduced parameter was examined through several experiments. As a result, it was confirmed that the drag coefficient deduced by the model is accurate enough when the number of the given observation data is sufficient compared with the number of the unknown parameter. It was also confirmed that the accuracy of the deduced coefficient can be improved by adding an a priori condition even if the number of the observation data is insufficient.
DOWNSCALING EFFECTS ON MODELLING WAVES, TIDES AND STORM SURGE
Authors: Chen Yongping , Pan Shunqi , Wolf Judith , Du Yanliang
Published: October 2012

This paper presents the results of downscaling effects when modelling waves, tides and storm surge using a nested modelling system. In this study, the coupled POLCOMS/ProWAM models are used, with 3 nested computational domains, the largest of which covers part of north-eastern Atlantic Ocean with a coarse resolution grid and the smallest covers the surrounding waters of south-west Cornish coast of the UK with a finer resolution grid. Applying the identical surface wind forcing to all 3 computational domains and the wave and tide boundary conditions provided from the coarse to finer domains, the computed wave heights, tides and surge levels are examined at selected locations to study the downscaling effects. The results show that downscaling could considerably increase accuracy of model predictions in the local domain. For the particular test conditions used in the present study, 3-level and 2-level downscaling produces similar results in the local domain. The results also indicate that downscaling with reduction of grid resolution by 6 times is acceptable for the study site.
MODELING OF THE REYNOLDS STRESS IN THE BURSTING LAYER AFFECTED BY TYPHOON
Authors: Murakami Tomokazu , Yoshino Jun , Yasuda Takashi
Published: October 2012

When large and intensive water surface displacements are caused by developed wind waves due to a typhoon, it is impossible in the Eulerian coordinate system to measure water particle velocities continuously in a domain between the wave trough level and the mean water level. Consequently, the domain between the wave trough level and the mean water level becomes a void zone where the Reynolds stress cannot be described. By treating the sea surface boundary layer including the void zone as a bursting layer, we modeled the Reynolds stress in the bursting layer. Validity of that modeling was verified by performing comparisons with experimentally obtained results.
WAVE GROWTH UNDER VARIABLE WIND CONDITIONS
Authors: Alomar Marta , Bolaños- Sánchez Rodolfo , Sanchez-Arcilla Agustín , Sairouni Abdel
Published: October 2012

Parametric wave growth curves are commonly used to empirically calculate wave height under fetch limited conditions and to tune the source functions of spectral wave models. There is not a unique wave growth function and many deviations from the first similarity laws have been reported. The applicability of the commonly used functions in variable wind conditions is expected to be limited. In this study we calculated wave growth curves with data from an instrumental set-up in the north-western Mediterranean. This region is characterized by non-homogeneous wind conditions (both in time and space). The first growth functions we calculated from the observations suggested higher wave growth rates than previously described by other authors. A close look to the sources of discrepancy in the calculations under such wind conditions revealed the importance to accurately separate sea from swell and to use only locally generated sea. The source of the wind data used for the scaling law is thought to be responsible for the remaining discrepancies from the commonly used growth functions. Wind and wave data from a high resolution simulation were used to calculate the growth functions from a spectral wave model, and to explore the importance of using in-situ wind measures to scale the variables. Simulated wave growth rates are lower than observed and lower than previously reported by other authors. Wind measurements from the most offshore buoy seem to be representative enough of the winds over the entire area. The results support the applicability of the well-known functions in the region of interest when certain conditions are met; i.e. pure wind sea conditions, and choosing a representative wind speed to scale the variables.
MODELING OF WAVE-CURRENT INTERACTION USING A MULTIDIRECTIONAL WAVE-ACTION BALANCE EQUATION
Authors: Ding Yan , Wang Sam S. Y.
Published: October 2012

This study presents an integrated numerical model to simulate wave deformation/transformation in tidal inlets or river mouths with ambient currents (e.g. tidal currents, river inflows) by carefully modeling the effect of wave-current interaction. A multidirectional wave-action balance equation is used to compute random/directional wave processes such as diffraction, refraction, shoaling, wave breaking, as well as wave-current interaction. This wave action model is coupled with a two-dimensional hydrodynamic model, the feedback effect of wave and current can be effectively simulated. This model is validated by simulating wave laboratory experiments in an inlet entrance, and waves and tidal currents in Grays Harbor, WA by using available field observation data in 1999. The capabilities of the wave model for simulating wave-current interaction and the corresponding breaking effect are confirmed in the study.
NUMERICAL ANALYSIS OF BULK DRAG COEFFICIENT IN DENSE VEGETATION BY IMMERSED BOUNDARY METHOD
Authors: Suzuki Tomohiro , Arikawa Taro
Published: October 2012

In this paper, bulk drag coefficient in rigid dense vegetation is investigated mainly by using a three dimensional numerical simulation model CADMAS-SURF/3D by incorporating Immersed Boundary Method to calculate flow around the vertical cylinder in the Cartesian grid. Large Eddy Simulation is also incorporated as a turbulence model. Firstly, validation of the developed model is conducted with a single cylinder in the flow field based on literature. All the results obtained here (Re=300, 3,900 and 8,000) show good agreement with the reference data in literature. After the validation, multiple cylinders are allotted in three different densities (S/D=2.8, 2.0, 1.4) in a numerical wave tank and numerical simulations are conducted to investigate bulk drag coefficient. The result shows that the ratio of bulk drag coefficient to drag coefficient, which represents a reduction, is not just a function of density but a function of parameter 2a/S, in which 2a is stroke of the motion and S is cylinder distance. 2a is less than S, the effect of the density is neglected because the wake does not reach the other cylinders even when the density is high. On the contrary, it might affect the ratio of bulk drag coefficient to drag coefficient when the stroke of the motion is larger than the cylinder distance even when the density is low. In general, the ratio of bulk drag coefficient to drag coefficient decreases when 2a/S increases.
RESPONSE OF POSIDONIA OCEANICA TO WAVE MOTION IN SHALLOW-WATERS - PRELIMINARY EXPERIMENTAL RESULTS
Authors: Cavallaro Luca , Lo Re Carlo , Paratore Giovanni , Viviano Antonino , Foti Enrico
Published: October 2012

Aim of the present work is to contribute to the knowledge about the interaction between the flow induced by wave and the aquatic vegetation. More in details the results of preliminary tests of an experimental laboratory investigation about the response of a Posidonia Oceanica meadow to wave motion in shallow waters is reported. A wide attention was posed to the behavior of a synthetic plants with plastic material. To this aim an image acquisition technique was used to analyze and compare the movement of both the artificial plant and the real one. The experiments carried out about the interaction between the artificial meadow and the waves showed a significant wave dumping, in particular in the case of plants having the same length of the water depth.
ON THE EFFECTIVENESS OF MANGROVES IN ATTENUATING CYCLONE - INDUCED WAVES
Authors: Narayan Siddharth , Suzuki Tomohiro , Stive Marcel J.F. , Verhagen Henk Jan , Ursem W.N.J. , Ranasinghe Roshanka
Published: October 2012

A study of the effectiveness of mangroves in attenuating cyclone- induced waves was done using the SWAN 40.81 numerical model. Hydraulic parameters during extreme events and local mangrove vegetation parameters were estimated for the Kanika Sands mangrove island near the upcoming Dhamra Port in Orissa, India. Simplified generic analyses were first conducted to obtain insights into the characteristics and behaviour of the model and the system. These were used to select relevant scenarios for simulations of actual conditions at the case-study site. The mangroves were found to be effective in reducing wave heights at the port behind the island though the effectiveness is limited by its geometry and distance from the port. The presence of vegetation has a marked effect though the effect of a variation in vegetation factor is limited. An optimum cross-shore width range for maximum protection was quantified.
AN EXPERIMENTAL STUDY OF WAVE AND CURRENT-INDUCED FORCES ON A COMPACT LINEAR ARRAY OF VERTICAL CYLINDERS IN SHALLOW WATER
Authors: Kudeih Mohamed , Cornett Andrew , Nistor Ioan
Published: October 2012

Arrays of vertical cylinders are essential components of many coastal structures, such as bridge piers, platform legs, and pile breakwaters. Thus, estimating the maximum wave and current-induced forces and moments on such structures is most important. Following a thorough literature review, the authors proceeded with an experimental study in order to investigate the forces exerted by random waves and a superimposed current on an array of three vertical cylinders as a function of the inter-cylinder gap and the angle of wave incidence over a wide range of wave and current conditions in shallow water.
IH-3VOF: A THREE-DIMENSIONAL NAVIER-STOKES MODEL FOR WAVE AND STRUCTURE INTERACTION
Authors: Lara Javier , Losada Inigo Javier , Del Jesus Manuel , Barajas Gabriel , Guanche Raul
Published: October 2012

This paper describes the capability of a new model, called IH-3VOF to simulate wave-structure interaction problems using a three-dimensional approach. The model is able to deal with physical processes associated with wave interaction with porous structures. The model considers the VARANS equations, a volume-averaged version of the traditional RANS (Reynolds Averaged Navier-Stokes) equations. Turbulence is modeled using a k-ï¥ approach, not only at the clear fluid region (outside the porous media) but also inside the porous media. The model has been validated using laboratory data of free surface time evolution in a fish tank containing a porous dam. Numerical simulations were calibrated by adjusting the porous flow empirical coefficients for two granular material characteristics. Sensitivity analysis of porous parameters has also been performed. The model is proven to reproduce with a high degree of agreement the free surface evolution during the seeping process. Simulations of a three- dimensional porous dam breaking problem has been studied, showing the excellent performance of the model in reproducing fluid patterns around a porous structure. The model is powerful tool to examine the near-field flow characteristics around porous structures in three dimensional flow conditions.
THE INTERACTION OF OBLIQUE WAVES WITH A PARTIALLY IMMERSED WAVE ABSORBING BREAKWATER
Authors: Liu Yong , Li Yucheng
Published: October 2012

By considering obliquely incident waves, the hydrodynamic performance of a partially immersed wave absorbing breakwater is examined in this study. The breakwater consists of a perforated front barrier and a solid rear barrier. The two barriers are both partially immersed with the same draft. An analytical solution based on the linear potential theory is developed to calculate the reflection and transmission coefficients of the breakwater and the wave forces acting on the barriers. Some useful results are presented according to numerical examples. The present solution may be used at a preliminary design stage in practical engineering.
A SMALL-SCALE FIELD EXPERIMENT FOR THE VALIDATION OF A THEORY ON REFLECTION OF NONLINEAR SHORT-CRESTED WAVE GROUPS
Authors: Romolo Alessandra , Arena Felice
Published: October 2012

A closed-form solution of free surface displacement and velocity potential for nonlinear short-crested (3D) wave groups interacting with a reflective sea wall is presented. The theory is applied to investigate the fluctuation wave pressures when an exceptionally high crest or deep trough occurs on the reflective wall. A characteristic behaviour has been observed. Due to non-linearity, on one hand, great reduction of the highest crest and enhancement of the deepest troughs on wave pressures are realized; on the other hand, the profiles show always a strong asymmetry between the absolute maxima and the minima and sometimes the formation of characteristic humped wave pressures corresponding to the impact on the structure of the highest wave crest. All the theoretical results have been validated through a small-scale field experiment carried out at the Natural Ocean Engineering Laboratory (N.O.E.L., www.noel.unirc.it) of Reggio Calabria (Italy).
BREAKING CRITERIA FOR LABORATORY EXPERIMENTS BASED ON THE PHASE-TIME-METHOD (PTM)
Authors: Irschik Kai , Schimmels Stefan , Oumeraci Hocine
Published: October 2012

Breaking waves generated by focusing of transient wave packets have been analyzed. By a comparison of video data and gauge measurements the threshold frequency for the use of the PTM as a breaking criterion is derived. The present result is slightly higher than the original value of Zimmermann & Seymour (2002) for spilling breakers, but confirms the results of Irschik & Oumeraci (2006). Additionally the use of the zero down-cross period Tz instead of the peak period TP is investigated. Both definitions lead for the present conditions with plunging breakers to almost identical results.
WAVES GENERATED BY TWO OR MORE SHIPS IN A CHANNEL
Authors: Nascimento Maria Francisca , Neves Claudio Freitas , Maciel Geraldo de Freitas
Published: October 2012

The numerical model FUNWAVE+Ship simulates the generation and propagation of ship waves to shore, including phenomena such as refraction, diffraction, currents and breaking of waves. The interaction of two wave trains, generated by ships moving either in the same direction at different speeds or in opposite directions, is studied. Focus is given to the wave orbital velocities and to the free surface pattern.
MULTI-DIMENSIONAL ERROR ANALYSIS OF NEARSHORE WAVE MODELING TOOLS, WITH APPLICATION TOWARD DATA-DRIVEN BOUNDARY CORRECTION
Authors: Jiang Boyang , Kaihatu James
Published: October 2012

As the forecasting models become more sophisticated in their physics and possible depictions of the nearshore hydrodynamics, they also become increasingly sensitive to errors in the inputs, such as errors in the specification of boundary information (lateral boundary conditions, initial boundary conditions, etc). Evaluation of the errors on the boundary is less straightforward, and is the subject of this study. The model under investigation herein is the Delft3D modeling suite, developed at Deltares (formerly Delft Hydraulics) in Delft, the Netherlands. Coupling of the wave (SWAN) and hydrodynamic (FLOW) model requires care at the lateral boundaries in order to balance run time and error growth. To this extent, we will use perturbation method and spatio-temporal analysis method such as Empirical Orthogonal Function (EOF) analysis to determine the various scales of motion in the flow field and the extent of their response to imposed boundary errors.
ENGINEERING DESIGN IN THE PRESENCE OF WAVE GROUPS
Authors: Shand Thomas D. , Peirson William L. , Cox Ronald J.
Published: October 2012

Determining the largest wave height, H which can occur in water of depth, d without breaking is a fundamental reference quantity for the design of coastal structures. Current design guidelines, used to predict the ratio of breaking height to depth (Hb/d), also known as the breaker index, are based on investigations which predominantly used monochromatic waves, thereby implicitly neglecting group effects. Groupiness or height modulation in wave trains is an inherent characteristic of freely propagating waves in deep water and has been shown within previous studies to induce breaker indices substantially exceeding those predicted by design guidelines. Additionally, the raw data upon which present design guidelines have been based exhibit considerable scatter. This scatter is surprising given the monochromatic and uniform nature of the laboratory waves.

A physical investigation at the Water Research Laboratory using new techniques for data extraction and visualisation has yielded new insights into the shoaling and breaking processes of regular and grouped waves and revealed deficiencies in the present design techniques. Monochromatic waves trains were found to develop amplitude modulation with distance along the flume due to non-linear instabilities. These instabilities are well recognized in deep-water waves and contribute to group development and the occurrence of low-probability extreme waves. These modulations induced variation in breaking wave heights, locations and derived breaker indices. Such modulation of initially regular wave trains is proposed as a possible cause of the scatter observed in raw laboratory breaker index data.

Wave group testing has revealed evolutionary cycles in local energy density during deep water propagation and that the spatial phasing of this evolution with the initiation of shoaling yielded considerably different shoaling and breaking regimes. Critically, smaller waves within the group, particularly those occurring at the front of the wave group were, at times, able to propagate into shallower water before breaking than is presently predicted by existing design guides. Causes for this discrepancy, including differences in definitions of water level and depth are investigated. However, discrepancies between observed and predicted values are found to remain. Revision to present design guidelines to directly incorporate non-linear group effects and group-induced water level variation are presented.
APPLYING THE WAVELET TRANSFORM TO STUDY THE FEATURES OF FREAK WAVES
Authors: Wu Li-Chung , Lee Beng-Chun , Kao Chia Chuen , Doong Dong-Jiing , Chang Chih-Chiang
Published: October 2012

The issues of freak waves are more and more popular since the late 1980s. This study tries to use the wavelet scalogram of freak wave records to investigate the energy characteristics during the occurrence of the freak waves. Through the analysis of the wave energy and phase, it is found that as freak waves occur, the component waves will lead to constructive superposition due to similar phases. The wavelet scalogram provides the other idea to explain the feature of freak waves.
FREAK WAVE AND WEATHER CONDITION
Authors: Mori Nobuhito , Mase Hajime , Yasuda Tomohiro
Published: October 2012

The kurtosis of the surface elevation, Benjamin-Feir Index (BFI) and directional spread are measures of nonlinear four-wave interactions and freak waves. The dependence of kurtosis, BFI and directional spread under typhoon conditions are examined by numerical simulations. The BFI is significantly large in the fourth quadrant of the typhoon while the directional spread is small in the fourth quadrant. It was found that the potentially possible area of freak wave occurrence is the fourth quadrant of the typhoon rather than the other quadrants.
ON THE CHOICE OF RANDOM WAVE SIMULATION IN THE SURF ZONE PROCESSES
Authors: Yuan Jing , Madsen Ole S.
Published: October 2012

In this paper, the two common approaches to account for wave randomness, the spectral approach and the wave-by-wave approach, are compared through numerical experiments conducted with the coupling of a surf zone hydrodynamic model and a bedload sediment transport model. Special attention is paid to the wave nonlinearity and net cross-shore bedload transport predictions. The two approaches are found to have negligible difference in their predictions of certain average hydrodynamics, such as wave heights, set-up and undertow. However, the wave-by-wave approach outperforms the spectral approach in the wave nonlinearity prediction, and the two approaches differ significantly in their predictions of wave-induced net cross-shore bedload transport which strongly depends on wave nonlinearity. This suggests the necessity of using the wave-by-wave approach. The computational efficiency of the wave-by-wave approach is also discussed.
Chugaev‐type bis(acyclic diaminocarbenes) as a new ligand class for the palladium‐catalyzed Mizoroki–Heck reaction
Authors: Owusu Millicent O. , Handa Sachin , Slaughter LeGrande M.
Published: October 2012

A series of differently substituted Chugaev‐type palladium bis(acyclic diaminocarbene) complexes was screened to identify the most active catalyst for Mizoroki–Heck coupling reactions of aryl bromides with styrene. The best catalyst, which contains three methyl groups on the bis(carbene) ligand, gives excellent coupling yields at 120 °C for both activated and deactivated aryl bromides. However, activity with aryl chlorides is limited to electron‐deficient examples. The optimized catalyst demonstrates limited air and moisture stability, giving reduced yields in couplings of activated aryl bromides in open‐flask conditions. The modular synthesis of this class of catalysts should allow further fine‐tuning of activity in Mizoroki–Heck and related coupling reactions. Copyright © 2012 John Wiley & Sons, Ltd.
Interactions with herring sperm DNA and biological studies of sparfloxacin drug‐based copper(II) compounds
Authors: Patel Mohan N. , Joshi Hardik N. , Patel Chintan R.
Published: October 2012

Copper(II) complexes of the type [Cu(SPF)(Ln)Cl] (where SPF is sparfloxacin and Ln = substituted terpyridines) were synthesized and found to have a distorted octahedral geometry. Superoxide dismutase‐like activity of the complexes was measured using a nitroblue tetrazolium/reduced nicotinamide adenine dinucleotide/phenazine methosulfate system and expressed in terms of the concentration of complex which terminates the formation of formazan by 50% (IC50 value), which was found to range from 0.572 to 1.522 µm. Interactions of the complexes with herring sperm DNA were studied by absorption titration, viscosity measurement and gel electrophoresis under physiological conditions. The antimicrobial efficiency of the complexes was tested against five different microorganisms and showed good biological activity. All the complexes showed good cytotoxic activity, with LC50 values ranging from 4.01 to 9.64 µg ml−1. Copyright © 2012 John Wiley & Sons, Ltd.
Dimeric ortho‐palladated homoveratrylamine as an efficient homogeneous catalyst for copper‐free Sonogashira cross‐coupling reaction
Authors: Hajipour Abdol R. , Rahimi Hannaneh , Rafiee Fatemeh
Published: October 2012

The catalytic activity of ortho‐palladated [Pd{C6H2(CH2CH2NH2)‐(OMe)2,3,4}(m‐Br)]2, a complex of homoveratrylamine in the copper‐free Sonogashira coupling reaction has been investigated. This complex is a catalyst that is efficient, stable and non‐sensitive to air and moisture in the Sonogashira reaction. In this homogeneous catalytic system, various aryl halides were efficiently coupled with phenylacetylene in mostly moderate to good yields in N‐methylpyrrolidone at 100 °C under copper‐free conditions. Copyright © 2012 John Wiley & Sons, Ltd.