Modeling of Sea Sea Surface Waves In Hurricane Basing On Self-Similarity Concept

2020 ◽  
Author(s):  
Mariya Yurovskaya ◽  
Vladimir Kudryavtsev ◽  
Bertrand Chapron
Keyword(s):  
Surface Waves ◽  
Wave Energy ◽  
Wind Field ◽  
Time Moment ◽  
Peak Frequency ◽  
Parametric Model ◽  
Spectral Peak ◽  
System Of Equations ◽  
Self Similarity ◽  
Wave Forecast

<p>The study is based on a simple parametric model, which is an extension of the self-similarity theory for surface waves generated by a wind field. According to the original similarity concept, the development of wind waves can be fully described using the scale of the fetch length (or time) and wind velocity. The aim of the work is to develop a parametric model to describe the wave generation in arbitrary spatio-temporal wind field. We assume that in this case similarity laws are also fulfilled, i.e., the rate of spectral the peak frequency and wave energy change is completely determined by the wave age. The source function is written in a form providing the stationary solution that corresponds to the well-known fetch law, confirmed in numerous experiments.</p><p>In order to extend the equations to the two-dimensional case, when the wind change occurs in both directions, it is assumed that the relations stay valid if the wind speed is replaced by its component in spectral peak direction. In this case, the system of equations should be supplemented by an expression for the evolution of spectral peak direction, describing its adaptating to the direction of non-uniform wind.</p><p>The algorithm for solving the complete system of equations describing the evolution of wave height, spectral peak frequency, its propagation direction and focusing/defocusing of wave energy, is based on the method of characteristics. To simulate the evolution of waves in a hurricane, we use the calculation in a non-stationary reference system associated with the hurricane. Coordinates, wave peak frequency, energy and direction are calculated along ray trajectory at every discrete time moment. To increase the stability of the numerical scheme, an implicit 4th-order Runge-Kutta method is used.</p><p>Test calculations were carried out for the case of the wave development from the coast with a uniform wind and then for an inhomogeneous cyclonic wind field for different hurricane speeds. The calculations reproduce the anisotropy of the energy distribution inside the hurricane and the effect of wave trapping by a moving cyclone. A comparison of the results with available field measurements of wave parameters in tropical cyclones showed their good agreement. The proposed algorithm can be used in wave forecast models and can serve for deeper understanding the wave field formation in extreme conditions.</p><p>The work was supported by Russian Science Foundation via grant 17-77-30019 and the Ministry of Education and Science of the Russian Federation under the State Assignment No. 0827-2018-0003.</p>

Directional Validation of Wave Predictions*

2007 ◽  
Vol 24 (3) ◽  
pp. 504-520 ◽  
Author(s):  
W. Erick Rogers ◽  
David W. C. Wang
Keyword(s):  
Ground Truth ◽  
Wave Model ◽  
Peak Frequency ◽  
Adaptive Method ◽  
Parametric Model ◽  
Spectral Peak ◽  
Systematic Bias ◽  
Data Adaptive ◽  
Interpretation Of Results

Abstract A methodology for quantitative, directional validation of a long-term wave model hindcast is described and applied. Buoy observations are used as ground truth and the method does not require the application of a parametric model or data-adaptive method to the observations. Four frequency ranges, relative to the peak frequency, are considered. The validation of the hindcast does not suggest any systematic bias in predictions of directional spreading at or above the spectral peak. Idealized simulations are presented to aid in the interpretation of results.

Estimates of Surface Waves Using Subsurface EM-APEX Floats under Typhoon Fanapi 2010

2018 ◽  
Vol 35 (5) ◽  
pp. 1053-1075 ◽  
Author(s):  
Je-Yuan Hsu ◽  
Ren-Chieh Lien ◽  
Eric A. D’Asaro ◽  
Thomas B. Sanford
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Wave Spectrum ◽  
Nonlinear Least Squares ◽  
Peak Frequency ◽  
Wave Propagation Direction ◽  
Model Studies ◽  
Surface Wave Propagation ◽  
Left Quadrant ◽  
Field Inclination

AbstractSeven subsurface Electromagnetic Autonomous Profiling Explorer (EM-APEX) floats measured the voltage induced by the motional induction of seawater under Typhoon Fanapi in 2010. Measurements were processed to estimate high-frequency oceanic velocity variance associated with surface waves. Surface wave peak frequency fp and significant wave height Hs are estimated by a nonlinear least squares fitting to , assuming a broadband JONSWAP surface wave spectrum. The Hs is further corrected for the effects of float rotation, Earth’s geomagnetic field inclination, and surface wave propagation direction. The fp is 0.08–0.10 Hz, with the maximum fp of 0.10 Hz in the rear-left quadrant of Fanapi, which is ~0.02 Hz higher than in the rear-right quadrant. The Hs is 6–12 m, with the maximum in the rear sector of Fanapi. Comparing the estimated fp and Hs with those assuming a single dominant surface wave yields differences of more than 0.02 Hz and 4 m, respectively. The surface waves under Fanapi simulated in the WAVEWATCH III (ww3) model are used to assess and compare to float estimates. Differences in the surface wave spectra of JONSWAP and ww3 yield uncertainties of <5% outside Fanapi’s eyewall and >10% within the eyewall. The estimated fp is 10% less than the simulated before the passage of Fanapi’s eye and 20% less after eye passage. Most differences between Hs and simulated are <2 m except those in the rear-left quadrant of Fanapi, which are ~5 m. Surface wave estimates are important for guiding future model studies of tropical cyclone wave–ocean interactions.

scholarly journals Performance of Linear Generator Designs for Direct Drive Wave Energy Converter under Unidirectional Long-Crested Random Waves

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5098
Author(s):  
Budi Azhari ◽  
Fransisco Danang Wijaya ◽  
Edwar Yazid
Keyword(s):  
Output Power ◽  
Wave Height ◽  
Wave Energy ◽  
Significant Wave Height ◽  
Analytical Calculation ◽  
Weight Ratio ◽  
Peak Frequency ◽  
Random Waves ◽  
Direct Drive ◽  
Significant Wave

For generating electricity, direct-drive wave energy converters (WECs) with linear permanent magnet generators (LPMGs) have advantages in terms of efficiency, simplicity, and force-to-weight ratio over WEC with rotary generators. However, the converter’s work under approaching-real wave conditions should be investigated. This paper studies the performance of a pico-scale WEC with two different LPMGs under unidirectional long-crested random waves. Different significant wave heights (using data in the Southern Ocean of Yogyakarta, Indonesia) and peak frequencies are tested. The JONSWAP energy spectrum is used to extract the wave elevations, while the MSS toolbox in MATLAB Simulink is employed to solve the floater’s dynamic responses. Next, the translator movements are extracted and combined with the flux distribution from FEMM simulation and analytical calculation, and the output powers are obtained. An experiment is conducted to test the output under constant speed. The results show for both designs, different tested significant wave height values produce higher output powers than peak frequency variation, but there is no specific trend on them. Meanwhile, the peak frequency is inversely proportional to the output power. Elimination of the non-facing events results in increasing output power under both parameters’ variation, with higher significant wave height resulting in a bigger increase. The semi iron-cored LPMG produces lower power loss and higher efficiency.

scholarly journals Wave Glider Observations of Surface Waves During Three Tropical Cyclones in the South China Sea

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1331 ◽  
Author(s):  
Di Tian ◽  
Han Zhang ◽  
Wenyan Zhang ◽  
Feng Zhou ◽  
Xiujun Sun ◽  
...  
Keyword(s):  
Surface Wave ◽  
South China Sea ◽  
Surface Waves ◽  
Tropical Cyclones ◽  
South China ◽  
Tangential Direction ◽  
China Sea ◽  
Wave Forecast ◽  
Wave Glider ◽  
The Right

Surface waves induced by tropical cyclones (TCs) play an important role in the air–sea interaction, yet are seldom observed. In the 2017 summer, a wave glider in the northern South China Sea successfully acquired the surface wave parameters when three TCs (Hato, Pakhar, and Mawar) passed though successively. During the three TCs, surface wave period increased from 4–6 s to ~8–10 s and surface wave height increased from 0–1 m to 3–8 m. The number of wave crests observed in a time interval of 1024 s decreased from 100–150 to 60–75. The sea surface roughness, a key factor in determining the momentum transfer between air and sea, increased rapidly during Hato, Pakhar, and Mawar. Surface waves rotated clockwise (anti-clockwise) on the right (left) side of the TC track, and generally propagated to the right side of the local cyclonic tangential direction relative to the TC center. The azimuthal dependence of the wave propagation direction is close to sinusoidal in a region within 50–600 km. The intersection angle between surface wave direction and the local cyclonic tangential direction is generally smallest in the right-rear quadrant of the TC and tends to be largest in the left-rear quadrant. This new set of glider wave observational data proves to be useful for assessing wave forecast products and for improvements in corresponding parameterization schemes.

scholarly journals Tropical cyclone wind field asymmetry-Development and evaluation of a new parametric model

2017 ◽  
Vol 122 (1) ◽  
pp. 458-469 ◽  
Author(s):  
Mohammad Olfateh ◽  
David P. Callaghan ◽  
Peter Nielsen ◽  
Tom E. Baldock
Keyword(s):  
Tropical Cyclone ◽  
Wind Field ◽  
Parametric Model

The Propagation of Wind Errors Through Ocean Wave Hindcasts

1996 ◽  
Vol 118 (3) ◽  
pp. 184-189 ◽  
Author(s):  
L. H. Holthuijsen ◽  
N. Booij ◽  
L. Bertotti
Keyword(s):  
Sensitivity Analysis ◽  
Mediterranean Sea ◽  
Wind Field ◽  
Ocean Wave ◽  
Wind Analysis ◽  
Wave Forecast ◽  
The Mediterranean ◽  
Field Errors

To estimate uncertainties in wave forecast and hindcasts, computations have been carried out for a location in the Mediterranean Sea using three different analyses of one historic wind field. These computations involve a systematic sensitivity analysis and estimated wind field errors. This technique enables a wave modeler to estimate such uncertainties in other forecasts and hindcasts if only one wind analysis is available.

scholarly journals A parametric model of surface waves as applied to the Arctic seas

2021 ◽  
pp. 515-530
Author(s):  
V. Cheshm Siyahi ◽  
V.N. Kudryavtsev ◽  
M.V. Yurovskaya
Keyword(s):  
Surface Waves ◽  
Parametric Model ◽  
The Arctic ◽  
Arctic Seas
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