MECHANISM AND COUNTERMEASURES OF WAVE OVERTOPPING FOR LONG-PERIOD SWELL IN COMPLEX BATHYMETRY

2012 ◽  
Vol 1 (33) ◽  
pp. 45
Author(s):  
Hiroaki Kashima ◽  
Katsuya Hirayama
Keyword(s):  
Deep Water ◽  
Wave Energy ◽  
Spatial Relationship ◽  
Wave Transformation ◽  
Wave Overtopping ◽  
Long Period ◽  
Wave Characteristics ◽  
Water Region ◽  
Wave Heights ◽  
Shallow Water Region

Recently, coastal disasters due to long-period swells induced by heavy storms and catastrophic typhoons have increased at Japanese coasts and harbors. Long-period swells are more susceptible to the bottom bathymetry of the offshore deep water region and their wave heights locally increase due to the concentration of wave energy caused by the complex bottom bathymetry in the relatively shallow water region. In addition, the wave overtopping rate may increase due to the long waves in front of the seawall induced by the long-period swells. However, the spatial relationship between wave characteristics and wave overtopping discharges in the complex bathymetry are not well known owing to a lack of detailed measurements. In this study, model experiments were conducted by using a large basin to investigate the spatial characteristics of wave transformation and wave overtopping focusing on the heavy wave overtopping damages caused by the arrivals of long-period swells at the Shimoniikawa Coast in 2008. Effective countermeasures against wave overtopping are also discussed based on their characteristics.

scholarly journals PROBABILITIES OF BREAKING WAVE CHARACTERISTICS

1970 ◽  
Vol 1 (12) ◽  
pp. 25 ◽  
Author(s):  
J. Ian Collins
Keyword(s):  
Shallow Water ◽  
Probability Density ◽  
Deep Water ◽  
Surf Zone ◽  
Probability Distributions ◽  
Rayleigh Distribution ◽  
Breaking Wave ◽  
Wave Characteristics ◽  
Probability Densities ◽  
Wave Heights

Utilizing the hydrodynamic relationships for shoaling and refraction of waves approaching a shoreline over parallel bottom contours a procedure is developed to transform an arbitrary probability density of wave characteristics in deep water into the corresponding breaking characteristics in shallow Water A number of probability distributions for breaking wave characteristics are derived m terms of assumed deep water probability densities of wave heights wave lengths and angles of approach Some probability densities for wave heights at specific locations in the surf zone are computed for a Rayleigh distribution in deep water The probability computations are used to derive the expectation of energy flux and its distribution.

scholarly journals Formulating Wave Overtopping at Vertical and Sloping Structures with Shallow Foreshores Using Deep-Water Wave Characteristics

2021 ◽  
Vol 147 (6) ◽  
pp. 04021036
Author(s):  
Christopher H. Lashley ◽  
Jentsje van der Meer ◽  
Jeremy D. Bricker ◽  
Corrado Altomare ◽  
Tomohiro Suzuki ◽  
...  
Keyword(s):  
Deep Water ◽  
Water Wave ◽  
Wave Overtopping ◽  
Wave Characteristics ◽  
Deep Water Wave

Using Fictitious Time Integration Method to Study Wave Propagation Over Arbitrary Bathymetry

2013 ◽  
Vol 29 (3) ◽  
pp. 551-558
Author(s):  
J.-Y. Chang ◽  
C.-C. Tsai ◽  
T.-W. Hsu
Keyword(s):  
Wave Propagation ◽  
Integration Method ◽  
Time Integration ◽  
Wave Transformation ◽  
Noise Resistance ◽  
Time Integration Method ◽  
Mild Slope Equation ◽  
Water Region ◽  
Shallow Water Region ◽  
Sloping Bottom

AbstractIn this study, the fictitious time integration method (FTIM) is applied to investigate wave propagation over an arbitrary bathymetry with measured uncertainty. The FTIM is used to convert the higher-order elliptic mild-slope equation (EMSE) into a FTIM like EMSE (FTIMEMSE). It has the advantage to describe wave transformation from deep water to shallow water region in a large coastal area with numerical efficiency. The validity of the noise resistance for the measured uncertainty of the bathymetry is also studied. In addition, typical examples for waves propagating over an elliptic shoal rest on a horizontal and sloping bottom is presented. It is concluded that the FTIM is robust in the numerical stability and capable of against the noise of the measurement.

Seismic wave energy inferred from long-period body wave inversion

1988 ◽  
Vol 78 (5) ◽  
pp. 1707-1724
Author(s):  
Masayuki Kikuchi ◽  
Yoshio Fukao
Keyword(s):  
Seismic Wave ◽  
Wave Energy ◽  
Body Wave ◽  
Empirical Relation ◽  
P Waves ◽  
Average Value ◽  
Long Period ◽  
Wave Inversion ◽  
Moment Ratio ◽  
Order Of Magnitude

Abstract The seismic wave energy is evaluated for 35 large earthquakes by inverting far-field long-period P waves into the multiple-shock sequence. The results show that the seismic wave energy thus obtained is systematically less than that inferred from the Gutenberg-Richter's formula with the seismic magnitude. The difference amounts to one order of magnitude. The results also show that the energy-moment ratio is well confined to a narrow range: 10−6 < ES/Mo < 10−5 with the average of ∼5 × 10−6. This average value is exactly one order of magnitude as small as the energy-moment ratio inferred from the Gutenberg-Richter's formula using the moment magnitude. Comparing the energy-moment ratio with Δσo/2μ, where Δσo and μ are the stress drop and the rigidity, we obtain an empirical relation: ES/Mo ∼ 0.1 × Δσ0/2μ. Such a relation can be interpreted in terms of a subsonic rupture where the energy loss due to cohesion is not negligible to the seismic wave energy.

GEK measurements in a shallow water region

1981 ◽  
Vol 37 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Yutaka Nagata ◽  
Kimie Yonemura ◽  
Hideo Nishida
Keyword(s):  
Shallow Water ◽  
Water Region ◽  
Shallow Water Region

Analysis of Wave Energy Sources in the North Atlantic Waters in View of Design Challenges

2016 ◽  
Author(s):  
Jose V. Taboada ◽  
Hirpa G. Lemu
Keyword(s):  
Renewable Energy ◽  
North Atlantic ◽  
Wave Energy ◽  
Energy Resources ◽  
Structural Performance ◽  
Energy Sources ◽  
Wave Power ◽  
Wave Statistics ◽  
Wave Characteristics

This paper describes a wave energy analysis of North Atlantic waters and provides an overview of the available resources. The analysis was conducted using a scatter diagram data combined with wave statistics and empirical parameters given by wave height and periods. Such an overview is instrumental for modelling of wave energy sources, design of wave energy converter (WEC) devices and determination of locations of the devices. Previous survey of wave energy resources widely focused on determination of the reliability on installations of WECs. Though the renewable energy source that can be utilized from the waves is huge, the innovative work in design and development of WECs is insignificant and the available technologies still require further optimization. Furthermore, the wave potential of North Atlantic waters is not sufficiently studied and documented. Closer review of the literature also shows that wave energy conversion technology, compared with other conversion machines of renewable energy sources such as wind energy and solar energy, seems still immature and most of the research and development efforts in this direction are limited in scope. The design of energy converters is also highly dictated by the wave energy resource intensity distribution, which varies from North to South hemisphere. The immaturity of the technology can be attributed to several factors. Since there are a number of uncertainties on the accuracy of wave data, the design, location and installation of WECs face a number of challenges in terms of their service life, structural performance and topological configuration. As a result, collection and assessment of wave characteristics and the wave state conditions data serve as key inputs for development of robust, reliable, operable and affordable wave energy converters. The fact that a number of variables are involved in wave distribution characteristics and the extraction of wave power, treating these variables in the design process imposes immense challenges for the design optimization and hence the optimum energy conversion. The conversion machines are expected to extract as high wave energy as possible while their structural performance is ensured. The study reported in this paper is to analyse wave data over several years of return periods with a detailed validation for wave statistics and wave power. The analysis is intended to contribute in better understanding of the wave characteristics with influencing parameters that can serve as design optimization parameters. A method is proposed to conduct a survey and analysis of the available wave energy resources and the potential at cited locations. The paper concludes that wave energy data accuracy is the baseline for project scoping, coastal and offshore design, and environmental impact assessments.

scholarly journals Wave Transformation for International Hub Port Planning (Transformasi Gelombang untuk Perencanaan Pelabuhan Hub Internasional)

2015 ◽  
Vol 20 (1) ◽  
pp. 9
Author(s):  
Denny Nugroho Sugianto ◽  
Purwanto Purwanto ◽  
Andika B Candra
Keyword(s):  
Wave Height ◽  
Vital Role ◽  
Ocean Wave ◽  
Wave Transformation ◽  
Wave Refraction ◽  
Wave Characteristics ◽  
Maximum Period ◽  
Wave Patterns ◽  
Port Planning ◽  
North Sumatra

Indonesia merupakan salah satu negara kepulauan terbesar di dunia sehingga peran pelabuhan sangat vital dalam pembangunan ekonomi. Pelabuhan bukan hanya sekedar sebagai pelengkap infrastruktur, melainkan harus direncanakan dan dikelola dengan baik serta memperhatikan fenomena dinamika perairan laut seperti pola gelombang laut. Data gelombang laut menjadi faktor penting dalam perencanaan tata letak dan tipe bangunan pantai karena dipengaruhi oleh tinggi gelombang signifikan, tunggang pasang surut dan transformasi gelombang. Penelitian ini mengalisis karaketristrik dan bentuk transformasi gelombang untuk perencanaan Pelabuhan Hub Internasional, sebagai studi kasus adalah pelabuhan di Kuala Tanjung, Kabupaten Batu Bara. Pelabuhan di Kuala Tanjung merupakan salah satu dari 2 pelabuhan hub internasional yang direncanakan akan dibangun oleh pemerintah Indonesia. Metode yang digunakan adalah metode kuantitatif yang dilakukan dengan perhitungan statistik dan pemodelan matematik dengan modul hydrodinamic dan spectral wave untuk mengetahui arah penjalaran dan transformasi gelombang. Hasil dari data ECMWF selama 1999–Juni 2014, diketahui tinggi gelombang signifikan (Hs) maksimum mencapai 1,69 m dan periode maksimum 8 detik. Karakteristik gelombang termasuk klasifikasi gelombang laut transisi dengan nilai d.L-1 berkisar anrata 0,27–0,48 dan berdasarkan periodenya diklasifikasikan sebagai gelombang gravitasi.Transformasi gelombang terjadi akibat pendangkalan dengan koefesian pendangkalan Ks 0,93–0,98 dan proses refraksi gelombang dengan koefesien Kr 0,97–0,99. Tinggi gelombang pecah Hb sebesar 1,24 meter dengan kedalaman gelombang pecah db sebesar 1,82 meter. Efektifitas desain bangunan terminal di Pelabuhan Kuala Tanjung secara keseluruhan untuk sepanjang musim sebesar 79,8% atau dapat dikatakan cukup efektif dalam meredam gelombang. Kata kunci: transformasi gelombang, tinggi dan periode gelombang, pelabuhan Indonesia is one of the largest archipelagic countries in the world, therefore port has vital role in economic development. Port is not just as a complement to the infrastructure, but it must be planned and managed properly and attention to the dynamics of marine phenomena such as ocean wave patterns. Ocean wave data become important factors in planning coastal building, since it is influenced by wave height, tides and waves transformation. The purpose of this study was to analyse characteristic and forms wave transformations for planning of international hub port at Kuala Tanjung, Baru Bara District North Sumatra. This port is one of two Indonesian government's plan in the development of international hub port. Quantitative method was used in this study by statistical calculations and mathematical modeling with hydrodinamic modules and spectral wave to determine the direction of wave propagation and transformation. Results show that based on ECMWF data during 1999-June 2014, known significant wave height (Hs) maximum of 1.69 m and maximum period (Ts) of 8 secs. The classification wave characteristics iswave transition (d.L-1: 0.27–0.48) and by the period are classified as gravitational waves. Wave transformation occurs due to the soaling, withKs 0.93–0.98 and the wave refraction Kr 0.97–0.99. Whereas Hb of 1.24 meters anddb 1.82 meters. The effectiveness of the design of the terminal building at the Port of Kuala Tanjung overall for the season amounted to 79.8%, which is quite effective in reducing the wave. Keywords: wave transformation, wave height and period, Port of Kuala Tanjung

Feasibility of the Potential for Wave and Wind Energy Hybrid Farm to Supply Offshore Oil Platform in Gulf of Mexico

2021 ◽  
Author(s):  
Chengcheng Gu ◽  
Hua Li ◽  
Francisco Haces-Fernandez
Keyword(s):  
Gulf Of Mexico ◽  
Wind Energy ◽  
Deep Water ◽  
Wave Energy ◽  
Oil And Gas ◽  
Hybrid Wave ◽  
Hybrid Energy ◽  
Daily Energy ◽  
Offshore Oil And Gas ◽  
Offshore Oil

Abstract Offshore oil and gas platforms use gas turbine with natural gas or fuel diesel for their high demand of power. Due to the declining amount of gas available, high carbon footprint, increasing cost of fuel and inefficient operating, alternative energy options are necessary and imminent. Most offshore oil and gas platforms locate in deep water surrounded by huge amount of energetic wave resources, hence, the feasibility of supplying offshore oil facilities electricity by hybrid wave and wind energy farms based on daily energy power production instead of annual average was conducted in this project. The hybrid energy farm was modeled and validated by applying meteorological data in Gulf of Mexico area from WaveWatch III system. With the hindcast wave and wind condition data from 1979 to 2019, daily energy generation of the hybrid energy farm was estimated. Meantime, the feasibility of suppling offshore oil and gas facilities by the proposed combined hybrid farm was assessed. The project optimized the configuration of the hybrid wave and wind energy farm to satisfy offshore oil and gas platform demands and reduce the variation of power generation, so that it may be feasibility to gradually substitute the gas turbines. Through matching the local wave and wind conditions, the project was able to maximize the power output while minimize the variation within limited ocean surface area. The project addressed the advantages of hybrid wave and wind devices, as well as theoretical prospection of wave harvesting device and wind turbine combination. To validate the proposed optimization model, a case study was explored by using Vesta V90 3MW wind turbines and Pelamis 750kW wave energy converters to supply five offshore platforms in more than 45 m deep water areas. The results indicated the possibility of bringing wave energy into large commercial operation and utilization with minor investment and environmental impact.

scholarly journals Nearshore Wave Transformation Domains from Video Imagery

2019 ◽  
Vol 7 (6) ◽  
pp. 186 ◽  
Author(s):  
Umberto Andriolo
Keyword(s):  
Sediment Transport ◽  
Intensity Variation ◽  
Wave Transformation ◽  
Physical Processes ◽  
Pixel Intensity ◽  
Wave Characteristics ◽  
Wide Range ◽  
Different Types ◽  
Propagation Properties ◽  
Wave Properties

Within the nearshore area, three wave transformation domains can be distinguished based on the wave properties: shoaling, surf, and swash zones. The identification of these distinct areas is relevant for understanding nearshore wave propagation properties and physical processes, as these zones can be related, for instance, to different types of sediment transport. This work presents a technique to automatically retrieve the nearshore wave transformation domains from images taken by coastal video monitoring stations. The technique exploits the pixel intensity variation of image acquisitions, and relates the pixel properties to the distinct wave characteristics. This allows the automated description of spatial and temporal extent of shoaling, surf, and swash zones. The methodology was proven to be robust, and capable of spotting the three distinct zones within the nearshore, both cross-shore and along-shore dimensions. The method can support a wide range of coastal studies, such as nearshore hydrodynamics and sediment transport. It can also allow a faster and improved application of existing video-based techniques for wave breaking height and depth-inversion, among others.

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