scholarly journals Estimating Waves and Currents at the Saltmarsh Edge Using Acoustic Doppler Velocimeter Data

2021 ◽  
Vol 8 ◽  
Author(s):  
Bing Liu ◽  
Yining Chen ◽  
Tinglu Cai ◽  
Yan Li ◽  
Li Sun
Keyword(s):  
Wave Energy ◽  
Estimation Method ◽  
Tidal Currents ◽  
Phase Method ◽  
Acoustic Doppler Velocimeter ◽  
Field Observations ◽  
Wave Method ◽  
Current Information ◽  
Wave Parameters ◽  
Waves And Currents

Waves, currents, and related sediment transport are important factors driving the development of saltmarshes. Separating the effects of waves and currents accurately from simple field observations is a technical challenge in shallow water environments with limited inundation such as saltmarshes. In this paper, the estimation method of both wave and current information was studied mainly through the data obtained by a solely used field ADV (Acoustic Doppler Velocimeter, Vector). Phase and pressure inversion wave methods were both used to estimate wave parameters, which were then compared to synchronous observation by wave loggers at the front of a saltmarsh. Our results show that ADV is able to achieve simultaneous observations of tidal currents and waves independently. The pressure inversion wave method (r2 ∼ 0.996) is more effective than the phase method (r2 ∼ 0.876) in estimating wave energy when comparing with wave logger results. However, the former is more restricted by submergence depth and duration in field, while the latter provides cut-off frequencies for the pressure inversion wave method. Both methods can be combined to best estimate wave parameters from field ADV data. Further, hydrodynamic observation on a Scirpus mariqueter patch at the front of a saltmarsh was used as an application to indicate the importance of obtaining both wave and current information from field data. The patch was found to mainly reduce the advection of tidal currents, but it slightly increases wave energy. Therefore, it is necessary to consider the different effects of plants on tidal currents and waves simultaneously in field observations. This study confirms that ADV and associated analysis can detect waves and currents at reliable accuracy at the marsh edge, which is vital in assessing the long-term resilience of marshes to sea level rise and increased storm severity.

UNDERWATER BARRED BEACH PROFILE TRANSFORMATION UNDER DIFFERENT WAVES CONDITIONS

2017 ◽  
Author(s):  
Olga Kuznetsova ◽  
Olga Kuznetsova ◽  
Yana Saprykina ◽  
Yana Saprykina ◽  
Boris Divinsky ◽  
...  
Keyword(s):  
Numerical Modelling ◽  
Coastal Zone ◽  
Wave Height ◽  
Wave Energy ◽  
Wave Period ◽  
Beach Profile ◽  
Infragravity Waves ◽  
Wave Parameters ◽  
Mean Wave Period

Based on numerical modelling evolution of beach under waves with height 1,0-1,5 m and period 7,5 and 10,6 sec as well as spectral wave parameters varying cross-shore analysed. The beach reformation of coastal zone relief is spatially uneven. It is established that upper part of underwater beach profile become terraced and width of the terrace is in direct pro-portion to wave height and period on the seaward boundary but inversely to angle of wave energy spreading. In addition it was ascertain that the greatest transfiguration of profile was accompanied by existence of bound infragravity waves, smaller part of its energy and shorter mean wave period as well as more significant roller energy.

Projected changes in wind wave directional spectra and their impact on coastal processes

2021 ◽  
Author(s):  
Hector Lobeto ◽  
Melisa Menendez ◽  
Iñigo J. Losada ◽  
Ottavio Mazzaretto
Keyword(s):  
Wave Energy ◽  
Wind Wave ◽  
Wave Climate ◽  
Wave Period ◽  
Standard Approach ◽  
Coastal Processes ◽  
Full Spectrum ◽  
Wave Parameters ◽  
Future Behavior ◽  
Projected Changes

<p>The assessment of the projected changes in wave climate due to climate change has been subject of study during the last two decades (Morim et al., 2018), largely due to the severe impacts these changes may have on coastal processes such as flooding and erosion. The wind wave climate is fully described by the sea surface elevation spectrum, which represents the distribution of energy resulting from the contributions of several superimposed waves with different periods and directions. Nevertheless, to this day the standard approach to address the future behavior of wind waves is based on the use of integrated wave parameters (e.g. significant wave height, mean wave period, mean wave direction) as a representation of the full spectrum. In this study, we analyze the changes in wave energy from directional spectra discretized in 24 directions and 32 frequencies in a number of locations distributed across all ocean basins, shedding light on the added value that an assessment based on the full spectrum offers with respect to the standard approach. In addition, the ESTELA method (Pérez et al., 2014) is applied to ease the understanding of the changes obtained in wave energy at the locations of study.</p><p>The spectral approach helps to assess the projected change in the energy of each wave system that reach a specific location. Results demonstrate that the use of integrated wave parameters can mask important information about the sign, magnitude and uncertainty of the actual projected changes in mean wave climate due to the offset of the expected variations in the different wave systems that integrate the spectrum. It is especially relevant at locations where an increase in the wave period or wave energy is hidden by the application of the standard approach, as these parameters are proven to play a key role in coastal processes. In addition, we reach relevant conclusions about the future behavior of swell systems. For instance, a robust increase in the energy carried by swells generated below 40°S can be observed in every ocean basin and both hemispheres, even beyond 30°N. Similarly, a decrease in the energy carried by northern swells can be observed close to the equator.</p>

Response of the Mega-Float Equipped With Novel Wave Energy Absorber

2003 ◽  
Author(s):  
Sotaro Masanobu ◽  
Shunji Kato ◽  
Katsuya Maeda ◽  
Yasuhiro Namba
Keyword(s):  
Wave Energy ◽  
Structural Design ◽  
Estimation Method ◽  
The Novel ◽  
Additional Structure ◽  
Energy Absorber ◽  
General Wave ◽  
Wave Drift ◽  
Drift Force ◽  
Hydroelastic Response

The hydroelastic response is significant from the viewpoint of the structural design of a Mega-Float. Equipping a Mega-Float with some additional structures, such as vertical plates, is one of the ways to reduce the hydroelastic response easily. However, in general, wave drift force acting on the Mega-Float may be increased, when the Mega-Float is equipped with the additional structures to reduce the response. In the present study, we developed a novel additional structure that was effective in the reduction of both hydroelastic response and wave drift force. Furthermore, we estimated the response of Mega-Float equipped with the additional structures, and compared the result with the value measured in at-sea experiments. As a result, we confirmed both the effectiveness of the novel additional structure and the validity of the estimation method.

Experimental and numerical investigation of wave-current forces on coastal bridge superstructures with box girders

2019 ◽  
Vol 23 (7) ◽  
pp. 1438-1453 ◽  
Author(s):  
Jiawei Zhang ◽  
Bing Zhu ◽  
Azhen Kang ◽  
Ruitao Yin ◽  
Xin Li ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Numerical Models ◽  
Wave Forces ◽  
Vertical Force ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Coastal Bridges ◽  
Girder Bridges ◽  
Wave Parameters ◽  
Waves And Currents

Coastal bridges are exposed to hurricane waves and storm surges during hurricanes, which threaten the safety of the superstructures. Since waves and ocean currents coexist in the natural marine environment and the action of currents leads to changes in wave parameters and thus affects wave loads, considering their interaction is necessary for the study of wave forces on coastal bridges. In this study, hydrodynamic loads on a box girder with the joint action of regular waves and currents are investigated with both experiments and numerical models. A series of experiments of wave forces that include conditions with different wave heights, current velocities, wave periods and submergence depths are conducted in a wave flume. Two-dimensional numerical simulations are performed to further investigate the mechanics of wave-current forces on box girder bridges. The wave parameters and wave forces of the numerical simulations are compared with the experimental results. The results indicate that a following current usually leads to higher maximum horizontal forces and lower maximum vertical forces. The opposing current results in a higher maximum hydrodynamic vertical force than following current with a low submergence depth. However, due to the joint effect of the wave parameters and structure position relationships, the behaviours of wave forces in other situations become complicated. It is anticipated that this study can provide experimental data of wave-current forces for the superstructures of box girder bridges and enhance the understanding of the mechanism of bridge damage by waves and currents.

Joint Distribution of Environmental Condition at Five European Offshore Sites for Design of Combined Wind and Wave Energy Devices

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Lin Li ◽  
Zhen Gao ◽  
Torgeir Moan
Keyword(s):  
Renewable Energy ◽  
Wave Energy ◽  
Environmental Data ◽  
Offshore Wind ◽  
Response Analysis ◽  
Energy Devices ◽  
Joint Distributions ◽  
Wave Parameters ◽  
Extreme Response

The design of wind turbines requires information about joint data for wind and wave conditions. Moreover, combining offshore wind and wave energy facilities is a potential way to reduce the cost of offshore wind farms. To design combined offshore renewable energy concepts, it is important to choose sites where both wind and wave energy resources are substantial. This paper deals with joint environmental data for five European offshore sites which serve as basis for the analysis and comparison of combined renewable energy concepts developed in the EU FP7 project—MARINA Platform. The five sites cover both shallow and deep water, with three sites facing the Atlantic Ocean and two sites in the North Sea. The long-term joint distributions of wind and wave parameters are presented for these sites. Simultaneous hourly mean wind and wave hindcast data from 2001 to 2010 are used as a database. The joint distributions are modeled by fitting analytical distributions to the hindcast data. The long-term joint distributions can be used to estimate the wind and wave power output from each combined concept and to estimate the fatigue lifetime of the structure. The marginal distributions of wind and wave parameters are also provided. Based on the joint distributions, contour surfaces are established for combined wind and wave parameters for which the probability of exceedance corresponds to a return period of 50 years. The design points on the 50-year contour surfaces are suggested for extreme response analysis of combined concepts.

scholarly journals DINÂMICA DA ZONA DE RASA DE SHOALING E O TRANSPORTE DE SEDIMENTOS NA DESEMBOCADURA SUL DO COMPLEXO ESTUARINO DE PARANAGUÁ – PR

2004 ◽  
Vol 54 ◽  
Author(s):  
Georgina Jacintho Martins ◽  
Eduardo Marone ◽  
Rodolfo José Angulo ◽  
Mauricio Almeida Noernberg ◽  
Clécio José Lopes De Quadros
Keyword(s):  
Complex Dynamics ◽  
Tidal Currents ◽  
Coastal Currents ◽  
Tidal Circulation ◽  
Wave Parameters ◽  
Tidal Changes ◽  
Hydrodynamic Potential ◽  
The Mean ◽  
The Waves

O presente trabalho caracteriza os parâmetros de ondas e analisa o potencial hidrodinâmico para o transporte de sedimentos por tração e de material particulado em suspensão, na costa adjacente à desembocadura sul do complexo estuarino de Paranaguá em decorrência do regime de ondas e das correntes de marés atuantes em períodos de mar calmo. A área estudada apresenta uma dinâmica complexa, devido à sua localização na saída de um grande estuário em uma costa com energia de onda relativamente elevada. Os objetivos principais foram os de caracterizar os parâmetros de ondas, avaliar o padrão de correntes junto à costa e estimar o potencial das correntes para o transporte de sedimentos. A caracterização dos parâmetros de ondas e das correntes paralelas à costa foi obtida através de correntômetro/ondômetro direcional eletromagnético InterOcean S4, fundeado imediatamente atrás da arrebentação das ondas na praia do Balneário Atami. Os fundeios foram realizados em períodos de baixa energia de ondas, quando era possível a sua instalação, sendo que os resultados são referentes a tais condições. Os resultados apontaram que a direção preferencial de chegada de ondas é de SE, sendo que a direção predominante de transporte médio longitudinal à costa foi de nordeste para sudoeste. As inversões das correntes associadas às variações da maré indicaram uma efetiva influência destas na direção do transporte. Com base nos resultados obtidos, são apresentadas sugestões visando incentivar a implementação de estratégias de monitoramento do fluxo de sedimentos costeiro. SHALLOW SHOALING ZONE DYNAMICS AND SEDIMENT TRANSPORT IN THE PARANAGUÁ BAY OUTLET Abstract This work presents a characterization of wave parameters and climate. It analyzes the hydrodynamic potential for sediments transport by traction as well by suspension (suspended particulate matter - SPM), carried out both by coastal currents, waves and the tidal circulation acting in the adjacent coast of the southern outlet of Paranaguá Estuarine Complex. This area presents a complex dynamics, due to its location, morphology and the interaction of several coastal processes acting among its limits. The main goal was to characterize the wave parameters and climate, to identify the coastal currents, and to understand the roles of these currents for the sediments transport, quantifying its magnitude. The characterization of the wave parameters and of the coastal currents was obtained through mooring a directional wave and current gauge InterOcean S4 immediately seaward of the surf of Atami beach, PR. The moorings were accomplished in periods of low wave energy, the only ones allowing the deployment, and the results are regarding such conditions. The results suggested that the preferential direction of wave propagation is SE and the predominant direction of the mean transport, longitudinal to the coast, was from Northeast to Southwest. The inversion of the longitudinal currents was associated to the tidal changes and they indicated an effective influence of the tidal currents, acting in the southern outlet of the Paranaguá estuary, in the direction of the mean mass transport. The hydrodynamic complexity of the place was directly related to these constraints, being linked to the net balance of the forcing of the tidal currents and the waves incidence. According to the obtained results, some suggestions were presented with the objective of suggesting strategies for the waves, currents and coastal transport studies, as a powerful tool for managing coastal zone problems.

scholarly journals Characterizing Wave Shape Evolution on an Ebb-Tidal Shoal

2019 ◽  
Vol 7 (10) ◽  
pp. 367 ◽  
Author(s):  
Floris de Wit ◽  
Marion Tissier ◽  
Ad Reniers
Keyword(s):  
Wave Breaking ◽  
Field Measurements ◽  
Tidal Currents ◽  
Wave Shape ◽  
Spatial Gradients ◽  
Nonlinear Energy Transfer ◽  
Waves And Currents ◽  
Wave Induced ◽  
Local Parameters ◽  
Nonlinear Energy

Field measurements of waves and currents were obtained at ten locations on an ebb-tidal shoal seaward of Ameland Inlet for a six-week period. These measurements were used to investigate the evolution of the near-bed velocity skewness and asymmetry, as these are important drivers for wave-induced sediment tranport. Wave shape parameters were compared to traditionally used parameterizations to quantify their performance in a dynamic area with waves and tidal currents coming in from different directions over a highly variable bathymetry. Spatially and temporally averaged, these parameterizations compared very well to observed wave shape. However, significant scatter was observed. The largest deviations from the parameterization were observed at the shallowest locations, where the contribution of wave-induced sediment transport was expected to be the largest. This paper shows that this scatter was caused by differences in wave-breaking, nonlinear energy transfer rate, and spatial gradients in tidal currents. Therefore, it is proposed to include the prior evolution of the wave before reaching a location in future parameterizations in numerical modeling instead of only using local parameters to predict wave shape.

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