scholarly journals WAVE STATISTICS ALONG THE NORTHERN COAST OF EGYPT

1974 ◽  
Vol 1 (14) ◽  
pp. 5
Author(s):  
M. Manohar ◽  
I.E. Mobarek ◽  
A. Morcos ◽  
H. Rahal
Keyword(s):  
Nile Delta ◽  
Spectral Band ◽  
Northern Coast ◽  
Wave Statistics ◽  
Wave Measurements ◽  
Narrow Spectral Band ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Nile Delta Coast ◽  
Comprehensive Study

As a forerunner of a comprehensive study of wave and energy climate of the Nile Delta coast covering a period of more than 50 years, wave measurements taken in 3 locations along the coast in the year 1972 were statistically analysed. Shortcut methods based on statistical approach were used to analyse the wave records enabling quicker analysis. Spectral analysis of the wave records indicates narrow spectral band similar to Raleigh distribution. The histograms and frequency distribution curves of significant wave heights, and the relationships between various statistical prarameters such as H , H,,,„, H,,„ and H also max 1/10' 1/3 rms agree closely with Raleigh distribution curves and parameters enabling the use of Raleigh distribution function in subsequent studies. Finally since the wave characteristics and wave energy climates are most important in the analysis of coastline changes, they are drawn from the data obtained from the analysis.

scholarly journals ON THE TRANSFORMATION OF WAVE STATISTICS DUE TO SHOALING

1988 ◽  
Vol 1 (21) ◽  
pp. 7
Author(s):  
E.P.D. Mansard ◽  
E.R. Funke ◽  
J.S. Readshaw ◽  
R.K. Girard
Keyword(s):  
Physical Model ◽  
Wave Energy ◽  
Low Frequency ◽  
Nearshore Zone ◽  
Frequency Wave ◽  
Wave Statistics ◽  
Wave Measurements ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Constant Slope

The results of a 1:40 scale physical model investigation into the shoaling process are described. The model simulated a nearly constant slope of 1:40 with wave measurements made at a depth of approximately 25 and 9 m. Two hundred individual tests were undertaken, with four offshore significant wave heights as the only test variant. The results indicate that the most severe nearshore wave conditions do not occur with the worst offshore conditions. There is evidence of a significant increase in low frequency wave energy in the nearshore zone.

An Idealization of Wave Scatter Diagram for Spectral Fatigue Analysis

2009 ◽  
Author(s):  
Min Han Oh ◽  
Ki Myung Lee ◽  
Young Sik Jang
Keyword(s):  
Fatigue Analysis ◽  
Scatter Diagram ◽  
Analysis Method ◽  
Sea State ◽  
Environmental Loads ◽  
Wave Data ◽  
Wave Measurements ◽  
Spectral Models ◽  
Wave Heights ◽  
Significant Wave Heights

A spectral fatigue analysis method is most popularly applied for the detailed design of FPSOs. As the environmental loads at the installation site are directly calculated in the spectral analysis, this method gives the most reliable results although it needs much time-consuming works to fully reflect the environmental loads. As the technology of wave measurements advances, the measured wave data increase. Also their spectral models are very complicated because these include many wave components such as swells and wind seas. Since much time and effort are needed to treat these enormous and complicated wave data for the spectral fatigue analysis, a rational idealization of wave data is definitely required. In this paper, wave scatter diagram at Offshore Nigeria was reviewed and their idealization method was proposed. The influence level of each sea state of the wave scatter diagram was identified considering the fatigue damage levels estimated from the significant wave heights and dominant fatigue load RAOs. The sea states giving small fatigue damages were lumped symmetrically by merging or disregarding while those giving large fatigue damages were kept as original. For the validation of this method, the comparisons of dominant fatigue loads and representative fatigue damages were presented for the idealized wave scatter diagram and the original one. From these comparison works, it was confirmed that the idealized wave scatter diagram gives reliable results with reduced amount of calculation work.

Experimental Investigation of Irregular Wave Cancellation Using a Cycloidal Wave Energy Converter

2012 ◽  
Author(s):  
Stefan G. Siegel ◽  
Casey Fagley ◽  
Marcus Römer ◽  
Thomas McLaughlin
Keyword(s):  
Wave Energy ◽  
Deep Ocean ◽  
Ocean Waves ◽  
Wave Energy Converter ◽  
Irregular Waves ◽  
Energy Converter ◽  
Irregular Wave ◽  
Wave Measurements ◽  
Wave Heights ◽  
Significant Wave Heights

The ability of a Cycloidal Wave Energy Converter (CycWEC) to cancel irregular deep ocean waves is investigated in a 1:300 scale wave tunnel experiment. A CycWEC consists of one or more hydrofoils attached equidistant to a shaft that is aligned parallel to the incoming waves. The entire device is fully submerged in operation. Wave cancellation requires synchronization of the rotation of the CycWEC with the incoming waves, as well as adjustment of the pitch angle of the blades in proportion to the wave height. The performance of a state estimator and controller that achieve this objective were investigated, using the signal from a resistive wave gage located up-wave of the CycWEC as input. The CycWEC model used for the present investigations features two blades that are adjustable in pitch in real time. The performance of the CycWEC for both a superposition of two harmonic waves, as well as irregular waves following a Bretschneider spectrum is shown. Wave cancellation efficiencies as determined by wave measurements of about 80% for the majority of the cases are achieved, with wave periods varying from 0.4s to 0.75s and significant wave heights of Hs ≈ 20mm. This demonstrates that the CycWEC can efficiently interact with irregular waves, which is in good agreement with earlier results obtained from numerical simulations.

Intercomparison of Wave Data Between Triaxys Directional Wave Buoy, ADCP, and Other Reference Wave Instruments

2005 ◽  
Author(s):  
H. H. Shih ◽  
C. Long ◽  
M. Bushnell ◽  
K. Hathaway
Keyword(s):  
Chesapeake Bay ◽  
Pressure Sensor ◽  
Sensor Array ◽  
Field Tests ◽  
Significant Wave ◽  
Wave Measurements ◽  
The Us ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Directional Wave

The use of Triaxys directional wave buoy and acoustic Doppler current profiler (ADCP) for wave measurements are relatively recent. The US National Oceanic and Atmospheric Administration’s (NOAA) National Ocean Service (NOS) acquired these instruments in 2001 and systematic laboratory and field tests were conducted during 2001–2002. This paper describes the field tests conducted near the US Army Corps of Engineers’ Field Research Facility (FRF) ocean pier and near the Barren Islands in the Chesapeake Bay. At the FRF site, Triaxys buoy wave measurements were compared with FRF’s field standards of pressure sensor arrays and Datawell Waverider buoy. For the Bay test, ADCP was compared with the Triaxys buoy. There are significant numbers of outlier in the Triaxys peak periods at both test sites. In the Chesapeake Bay, which is dominated by high frequency and low energy waves, there is much scatter in the Triaxys data for significant wave heights below 0.2 m. Detailed analyses were performed after these outliers and noisy data were removed. Statistics of differences in significant wave heights, peak periods and directions between each comparative pair were computed and characteristics of frequency and frequency-direction spectra were examined. Overall, correlations between each instrument pair are very good in significant wave heights, fair in wave peak periods (except the ADCP/Triaxys pair), and marginal in wave directions. Triaxys buoy compared better with Waverider buoy than with others. Both ADCP and FRF pressure sensor array exhibit higher resolution in detecting multi-modal and multi-frequency waves. In most cases, energy distribution of spectral peaks in Triaxys buoy data differs significantly from those obtained from FRF pressure sensor array and ADCP.

scholarly journals COMPREHENSIVE STUDY AND MONITORING PROGRAM FOR BEACHES AT VIÑA DEL MAR CHILE

2018 ◽  
pp. 43
Author(s):  
Benjamín Carrión ◽  
Rolando García
Keyword(s):  
Monitoring Program ◽  
Storm Event ◽  
Central Chile ◽  
Field Recording ◽  
Waves And Currents ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
The City ◽  
Topographic Surveys ◽  
Comprehensive Study

On August 8th 2015, an extreme storm event affected central Chile. Significant wave heights up to 5.0 m at a depth of 20m were estimated in front of Viña del Mar. Beaches suffered massive erosion and relevant damage to coastal infrastructure occur (Figure 1), jeopardizing the touristic industry of the city. These episodes motivated the execution of the largest comprehensive study and monitoring plan ever done on the littoral system of Viña del Mar. The study considered reviewing historical records, hydrological analysis of the related river basins, several bathymetric and topographic surveys, sediment samples, measurements of waves and currents, monitoring cameras for field recording and extensive numerical modelling.

scholarly journals Mobility of sediments due to wave action on the continental shelf of the Northern coast of the state of Bahia

2010 ◽  
Vol 58 (spe2) ◽  
pp. 57-63 ◽  
Author(s):  
Raissa Helena Simões Campos ◽  
José Maria Landim Dominguez
Keyword(s):  
Continental Shelf ◽  
Coarse Grained ◽  
Sidescan Sonar ◽  
Northern Coast ◽  
Shelf Area ◽  
Sediment Grain Size ◽  
Significant Wave ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Continental Shelf Area

The mobility of surface sediments on the continental shelf has been investigated in this study by the use of a simple model which relates significant wave height and period (Hsig and Tsig) along with median sediment grain size (D50). For the Hsig and Tsig values used, sediment mobilization occurs to a maximum depth of approximately 60m and encompasses virtually the entire continental shelf area. By contrast, average winter wave values of H and T can only remobilize half of this area. The seafloor area remobilized by significant wave heights and periods is in close agreement with the spatial distribution of coarse grained ripples (CGR) bedforms mapped with sidescan sonar.

SIMULATION OF NEARSHORE WAVES AND CURRENTS ALONG SALALAH COAST (OMAN) DURING THE TROPICAL CYCLONE ARB01

2017 ◽  
Author(s):  
AbdAlla M. AbdAlla ◽  
AbdAlla M. AbdAlla ◽  
Abkar A. Iraqi ◽  
Abkar A. Iraqi ◽  
Magdy M. Farag ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Domain Boundary ◽  
Circulation Model ◽  
Shielding Effect ◽  
Strong Current ◽  
Waves And Currents ◽  
Wave Heights ◽  
Nearshore Waves ◽  
Flood Period ◽  
Significant Wave Heights

Sea level and wave data at Salalah coast (Oman) were used to simulate nearshore waves and current during the tropical cyclone ARB01 (9 May2002). STWAVE model (Steady State Spectral Wave) was applied for nearshore wave simulation, while M2D model ((Two-Dimensional Depth Averaged circulation model) was used to simulate nearshore current. The results of simulations (taking into account the mutual effects of both current and waves) showed that: The significant wave heights generally decrease from about 6m at the domain boundary to about 1 m close to the coast. The wave heights during the ebb period were higher than that during the flood period by about 1.5m. Along Salalah coast, higher waves were found along the eastern side of the domain. This is because the shielding effect of breakwater, which protect the western part of the coast from high waves. Relatively Strong current with values up to 1.5 ms-1 were found in the nearshore region during both ebb and flood periods. The M2D model results also showed cyclonic circulations during these periods which help in the renewal of harbor waters. Generally, the model results showed good agreements with observations in the investigated area.

scholarly journals Comprehensive Wind and Wave Statistics and Extreme Values for Design and Analysis of Marine Structures in the Adriatic Sea

2021 ◽  
Vol 9 (5) ◽  
pp. 522
Author(s):  
Marko Katalinić ◽  
Joško Parunov
Keyword(s):  
Adriatic Sea ◽  
Extreme Values ◽  
Wave Climate ◽  
Offshore Structures ◽  
Model Parameters ◽  
Peak Period ◽  
Significant Wave ◽  
Wave Statistics ◽  
Wave Heights ◽  
Almost All

Wind and waves present the main causes of environmental loading on seagoing ships and offshore structures. Thus, its detailed understanding can improve the design and maintenance of these structures. Wind and wave statistical models are developed based on the WorldWaves database for the Adriatic Sea: for the entire Adriatic Sea as a whole, divided into three regions and for 39 uniformly spaced locations across the offshore Adriatic. Model parameters are fitted and presented for each case, following the conditional modelling approach, i.e., the marginal distribution of significant wave height and conditional distribution of peak period and wind speed. Extreme significant wave heights were evaluated for 20-, 50- and 100-year return periods. The presented data provide a consistent and comprehensive description of metocean (wind and wave) climate in the Adriatic Sea that can serve as input for almost all kind of analyses of ships and offshore structures.

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