PARAMETERIZATION OF NONLINEAR WAVE TRANSFORMATION ABOVE UNDERWATER STRUCTURES

2017 ◽  
Author(s):  
Yana Saprykina ◽  
Yana Saprykina
Keyword(s):  
Nonlinear Wave ◽  
Water Depth ◽  
Significant Wave Height ◽  
Relative Length ◽  
Wave Period ◽  
Wave Transformation ◽  
Mean Wave Period ◽  
The Mean ◽  
Underwater Structure ◽  
Underwater Structures

On the base of laboratory experiment a nonlinear wave transformation above underwater reef and trench was investigated. It was revealed that underwater trench and reef can decrease the mean wave period. Dependencies of changes of mean wave period and significant wave height on relative length of underwater structure and water depth above it were obtained. The changes of symmetry of waves passing above underwater structures are discussed.

PARAMETERIZATION OF NONLINEAR WAVE TRANSFORMATION ABOVE UNDERWATER STRUCTURES

2017 ◽  
Author(s):  
Yana Saprykina ◽  
Yana Saprykina
Keyword(s):  
Nonlinear Wave ◽  
Water Depth ◽  
Significant Wave Height ◽  
Relative Length ◽  
Wave Period ◽  
Wave Transformation ◽  
Mean Wave Period ◽  
The Mean ◽  
Underwater Structure ◽  
Underwater Structures

On the base of laboratory experiment a nonlinear wave transformation above underwater reef and trench was investigated. It was revealed that underwater trench and reef can decrease the mean wave period. Dependencies of changes of mean wave period and significant wave height on relative length of underwater structure and water depth above it were obtained. The changes of symmetry of waves passing above underwater structures are discussed.

Design Aspects of Breakwaters for Cold Climate Oil and Gas Terminals

2017 ◽  
Author(s):  
Isabel Jimenez Puente ◽  
Ove Tobias Gudmestad
Keyword(s):  
Oil And Gas ◽  
Barents Sea ◽  
Cold Climate ◽  
Wave Period ◽  
Wave Parameter ◽  
Special Importance ◽  
Mean Wave Period ◽  
The Mean ◽  
Selection For

This paper focuses on design aspects regarding breakwaters for cold climate terminals, in particular, the different types of berm breakwaters, their stability, armour mobility criteria and armour size. A methodology is analyzed in order to determine the mean weight of the heaviest armour class as a function of wave parameters such as the significant wave height and the mean wave period, both for non-reshaping and reshaping stable berm breakwaters. The influence of the wave period on the stone mass required will be of special importance in the discussion. This methodology will enable us to determine the required median armour weight for a specific wave parameter, being easily able to compare the feasibility of different concepts or availability of the required stone size at the location. As a case study, the breakwater selection for the Melkøya terminal in the Norwegian Barents Sea, is assessed through a comparison of the necessary armour unit masses for the different berm breakwaters. The armour mobility criteria currently established is reviewed and a recommendation for an updated criterion for the statically stable non-reshaped berm breakwater category is proposed.

scholarly journals ANFIS and ANN models for the estimation of wind and wave-induced current velocities at Joeutsu-Ogata coast

2015 ◽  
Vol 18 (2) ◽  
pp. 371-391 ◽  
Author(s):  
Morteza Zanganeh ◽  
Abbas Yeganeh-Bakhtiary ◽  
Takao Yamashita
Keyword(s):  
Wind Speed ◽  
Wave Height ◽  
Water Depth ◽  
Incident Wave ◽  
Wind Direction ◽  
Significant Wave Height ◽  
Wave Period ◽  
Inference System ◽  
Significant Wave ◽  
Wave Induced

In this study, the adaptive network-based fuzzy inference system (ANFIS) and artificial neural network (ANN) were employed to estimate the wind- and wave-induced coastal current velocities. The collected data at the Joeutsu-Ogata coast of the Japan Sea were used to develop the models. In the models, significant wave height, wave period, wind direction, water depth, incident wave angle, and wind speed were considered as the input variables; and longshore and cross-shore current velocities as the output variables. The comparison of the models showed that the ANN model outperforms the ANFIS model. In addition, evaluation of the models versus the multiple linear regression and multiple nonlinear regression with power functions models indicated their acceptable accuracy. A sensitivity test proved the stronger effects of wind speed and wind direction on longshore current velocities. In addition, this test showed great effects of significant wave height on cross-shore currents' velocities. It was concluded that the angle of incident wave, water depth, and significant wave period had weaker influences on the velocity of coastal currents.

Comparative wave measurements at a wave energy site with a recently developed low-cost wave buoy (Spotter), ADCP and pressure loggers

2021 ◽  
Author(s):  
Orrin Lancaster ◽  
Remo Cossu ◽  
Sebastien Boulay ◽  
Scott Hunter ◽  
Tom E. Baldock
Keyword(s):  
Wave Height ◽  
Wave Energy ◽  
Significant Wave Height ◽  
Low Cost ◽  
Wave Period ◽  
Wave Direction ◽  
Mean Values ◽  
Significant Wave ◽  
Wave Measurements ◽  
The Mean

AbstractWave measurements from a new, low-cost, real-time wave buoy (Spotter) are investigated in a comparative study as part of a site characterization study at a wave energy candidate site at King Island, Tasmania, Australia. Measurements from the Sofar Ocean Spotter buoy are compared with concurrent measurements from a Teledyne RD Instrument (RDI) 1200 kHz Work Horse ADCP and two RBRsolo3 D wave16 pressure loggers. The comparison period between 8th August – 12th October 2019 provides both the shallowest and longest continuous published comparison undertaken with the Spotter buoy.Strong agreement was evident between the Spotter buoy and RDI ADCP of key wave parameters including the significant wave height, peak wave period, and mean wave direction, with the mean values of those parameters across the full deployment period agreeing within 3%. Surface wave spectra and directional spectra are also analyzed with good agreement observed over the majority of the frequency domain, although the Spotter buoy records approximately 17% less energy within a narrow frequency band near the peak frequency when compared to the RDI ADCP. Measurements derived from the pressure loggers routinely underestimated the significant wave height and overestimated the mean wave period over the deployment period. The comparison highlights the suitability of the Spotter buoy for low-cost wave resource studies, with accurate measurements of key parameters and spectra observed.

scholarly journals BREAKING CRITERION ON NON-UNIFORMLY SLOPING BEACH

1986 ◽  
Vol 1 (20) ◽  
pp. 25
Author(s):  
Takashi Izumiya ◽  
Masahiko Isobe
Keyword(s):  
Experimental Data ◽  
Water Depth ◽  
Wave Period ◽  
Breaking Point ◽  
Bottom Slope ◽  
The Mean ◽  
Sloping Beach ◽  
Step Type

This paper deals with the breaker height on non-uniformly sloping beaches. A large number of experiments were carried out to obtain a breaking criterion on bar and step-type beaches. Based on the experimental data, a relationship among the breaker height, water depth, and wave period is investigated for various bottom configurations. As a result, the breaker height on non-uniformly sloping beaches is found to be well predicted by substituting an equivalent bottom slope in Goda's breaker index which has been obtained for uniformly sloping beaches. The equivalent bottom slope is defined as the mean slope in the distance of 5hg offshoreward from a breaking point, where hg denotes the water depth at the breaking point. The method for calculating the breaker height on natural beaches is also presented.

PHYSICAL INTERPRETATION OF WAVE BREAKING CRITERIA

2017 ◽  
Author(s):  
Sergey Kuznetsov ◽  
Sergey Kuznetsov ◽  
Yana Saprykina ◽  
Yana Saprykina ◽  
Boris Divinskiy ◽  
...  
Keyword(s):  
Nonlinear Wave ◽  
Wave Breaking ◽  
Second Harmonic ◽  
Vertical Axis ◽  
Breaking Waves ◽  
Wave Transformation ◽  
Spectral Structure ◽  
Similarity Parameter ◽  
Nonlinear Harmonics ◽  
The Waves

On the base of experimental data it was revealed that type of wave breaking depends on wave asymmetry against the vertical axis at wave breaking point. The asymmetry of waves is defined by spectral structure of waves: by the ratio between amplitudes of first and second nonlinear harmonics and by phase shift between them. The relative position of nonlinear harmonics is defined by a stage of nonlinear wave transformation and the direction of energy transfer between the first and second harmonics. The value of amplitude of the second nonlinear harmonic in comparing with first harmonic is significantly more in waves, breaking by spilling type, than in waves breaking by plunging type. The waves, breaking by plunging type, have the crest of second harmonic shifted forward to one of the first harmonic, so the waves have "saw-tooth" shape asymmetrical to vertical axis. In the waves, breaking by spilling type, the crests of harmonic coincides and these waves are symmetric against the vertical axis. It was found that limit height of breaking waves in empirical criteria depends on type of wave breaking, spectral peak period and a relation between wave energy of main and second nonlinear wave harmonics. It also depends on surf similarity parameter defining conditions of nonlinear wave transformations above inclined bottom.

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.

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