共查询到19条相似文献，搜索用时 328 毫秒
1.
ZHENGGuizhen SHENGLifang CONGPeixiu 《中国海洋大学学报(英文版)》2004,3(2):123-128
A mechanism is suggested in this paper concerning the effect of non-uniform current on the spectrum of short wind waves. According to this mechanism, a non-uniform current brings changes to the breaking criteria of short wind waves through modulating the surface drift, and hence enhances or weakens wave breaking. Some modification is proposed to the source term, which represents the spectral rate of wave energy dissipation due to wave breaking so that the source term can incorporate this mechanism. In order to illustrate whether this mechanism is significant, a real case is studied, in which the wind waves propagate on a tidal current flowing over the sea bottom covered with sand waves. Finally, the effect of the new mechanism on the equilibrium spectrum of small scale gravity waves is discussed. Numerical estimates suggest that, for water depths less than 50 m and wavelengths less than 1 m, this current field may result in distinct spatial variations of the wave breaking criteria, the spectral rate of wave energy dissipation and the equilibrium spectrum of short gravity waves. 相似文献
2.
It is traditionally assumed that the relationship between wave steepness and wave age is independent of the wind wave growth state. In fact, the traditional relationship can not describe the whole course of wind wave growth. This paper assumes that the relationship between wave steepness and wave age changes with the variety of dimensionless fetch. Based on the relationship proposed by Hou and Wen (1990), a new relationship in the course of wind wave growth is revealed. Comparisons between the present study and other previous relationships show that this new relationship explains better the observations than the other existing relationships.In the case of small fetch, wave age value increases more quickly than other models while it is in opposition to that in the case of large fetch. The result in present paper can clearly reflect the whole course of wind wave growth, it is an improvement for traditional results. 相似文献
3.
《中国海洋湖沼学报》2019,(6)
As concluded from physical theory and laboratory experiment, it is widely accepted that nonlinearities of sea state play an important role in the formation of rogue waves; however, the sea states and corresponding nonlinearities of real-world rogue wave events remain poorly understood. Three rogue waves were recorded by a directional buoy located in the East China Sea during Typhoon Trami in August 2013. This study used the WAVEWATCH Ⅲ model to simulate the sea state conditions pertaining to when and where those rogue waves were observed, based on which a comprehensive and full-scale analysis was performed. From the perspectives of wind and wave fields, wave system tracking, High-Order Spectral method simulation, and some characteristic sea state parameters, we concluded that the rogue waves occurred in sea states dominated by second-order nonlinearities. Moreover, third-order modulational instabilities were suppressed in these events because of the developed or fully developed sea state determined by the typhoon wave system. The method adopted in this study can provide comprehensive and full-scale analysis of rogue waves in the real world. The case studied in this paper is not considered unique, and rules could be found and confirmed in relation to other typhoon sea states through the application of our proposed method. 相似文献
4.
The inflow angle of tropical cyclones(TC) is generally neglected in numerical studies of ocean surface waves induced by TC.In this study,the impacts of TC inflow angle on ocean surface waves were investigated using a high-resolution wave model.Six numerical experiments were conducted to examine,in detail,the effects of inflow angle on mean wave parameters and the spectrum of wave directions.A comparison of the waves simulated in these experiments shows that inflow angle significantly modifies TC-induced ocean surface waves.As the inflow angle increases,the asymmetric axis of the significant wave height(SWH) field shifts 30u clockwise,and the maximum SWH moves from the front-right to the rear-right quadrant.Inflow angle also affects other mean wave parameters,especially in the rear-left quadrant,such as the mean wave direction,the mean wavelength,and the peak direction.Inflow angle is a key factor in wave models for the reproduction of double-peak or multi-peak patterns in the spectrum of wave directions.Sensitivity experiments also show that the simulation with a 40u inflow angle is the closest to that of the NOAA statistical SLOSH inflow angle.This suggests that 40u can be used as the inflow angle in future TC-induced ocean surface wave simulations when SLOSH or observed inflow angles are not available. 相似文献
5.
Based on up to date literature, this paper details the evolution of wave dependence of wind stress.Some typical models of the dependence of wind stress on waves are described in detail. Although there isno universally accepted theory and model, recent studies indicate that the wind strees strongly dependson the development state of sea waves, i. e., young seas are rougher than mature seas, in other words, thewind stress decreases with increasing wave age. 相似文献
6.
Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using the dispersion relation of water surface waves, we derive the slope wavenumber spectrum models of capillary and capillary-gravity waves. Simultaneously, by using the slope wavenumber models, the dependence of the slope wavenumber spectrum on wind speed is analyzed using data obtained in an experiment which was performed in a laboratory wind wave tank. Generally speaking, the slope wavenumber spectra are influenced profoundly by the wind speed above water surface. The slope wavenumber spectrum increases with wind speed obviously and do not cross each other for different wind speeds. But, for the same wind speed, the slope wavenumber spectra are essentially identical, even though the capillary and capillary-gravity waves are excited at different times and locations. Furthermore, the slope wavenumber spectra obtained from the models agree quite well with experimental results as regards both the values and the shape of the curve. 相似文献
7.
GUANChanglong SUNQun PhilippeFraunie 《青岛海洋大学学报(英文版)》2002,1(2):105-108
Combining the 3/2 power law proposed by Toba with the significant wave energy balance equation for wind waves, wave growth in deep water for short fetch is investigated. It is found that the variations of wave height and period with fetch have the form of power function with fractional exponents 3/8 and 1/4 respectively. Using these exponents in the power functions and through data fitting, the concise wind wave growth relations for short fetch are obtained. 相似文献
8.
The validation and assessment of Envisat advanced synthetic aperture radar (ASAR) ocean wave spectra products are important to their application in ocean wave numerical predictions. Six-year ASAR wave spectra data are compared with one-dimensional (1D) wave spectra of 55 co-located moored buoy observations in the northern Pacific Ocean. The ASAR wave spectra data are firstly quality control filtered and spatio-temporal matched with buoy data. The comparisons are then performed in terms of 1D wave spectra, significant wave height (SWH) and mean wave period (MWP) in different spatio-temporal offsets respectively. SWH comparison results show the evident dependence of SWH biases on wind speed and the ASAR SWH saturation effect. The ASAR wave spectra tend to underestimate SWH at high wind speeds and overestimate SWH at low wind speeds. MWP comparison results show that MWP has a systematic bias and therefore it should be bias-modified before used. The comparisons of 1D wave spectra show that both wave spectra agree better at low frequencies than at high frequencies, which indicates the ASAR data cannot resolve the high frequency waves. 相似文献
9.
《中国海洋大学学报(英文版)》2020,(5)
This study aims to estimate and predict the impact of climate change on typhoons and wave overtopping during typhoon progresses in Qingdao, China. The SWAN wave model is used to simulate wave elements. The scale coefficients of wave overtopping are estimated using an empirical prediction formula. A total of 75 tropical cyclones affected Qingdao from 1949 to 2019. These tropical cyclones can be grouped into eight categories according to typhoon tracks. Typhoon wind speed during Track G is projected to decrease, and those of the other seven typhoon progresses will increase by 0.35% – 0.75% in 2025, 0.69% – 1.5% in 2035, and 1.38% – 3.0% in 2055. The significant wave height and wave overtopping outside the bay are greater than those inside the bay. Among the 506 typical points selected, the maximum values of the significant wave height and wave overtopping inside the bay are mainly distributed in the range of 0 – 2 m and 0 – 60 m~3 km~(-1) s~(-1), respectively. The increments of the significant wave height and wave overtopping of Track F are most obvious. The significant wave height of Track F will increase by 50.5% in 2025, 51.8% in 2035, and 53.4% in 2055. In the 2℃ scenario, the maximum value of wave overtopping of Track F will increase by 21.9% in 2025, 24.3% in 2035, and 29.5% in 2055. In the 4℃ scenario, the maximum value of wave overtopping of Track F will increase by 21.9% in 2025, 24.3% in 2035, and 29.5% in 2055. 相似文献
10.
WANG Junrong LI Huajun LI Ping ZHOU Kai 《中国海洋大学学报(英文版)》2007,6(3):310-314
Coupled effects on a single point mooring(SPM) system subjected to the combined action of wind,waves and current are studied in this paper. Due to the complicatedness of the sea state and the huge size of the vessel,physical experimental study is both time consuming and uneconomical,whereas the numerical study is cost-effective and DNV software provides powerful SESAM software in solving the issues. This paper focuses on the modeling process of the SPM system,catenary equilibrium calculation,static analysis of the vessel in three different scenarios,and dynamic response simulation of the SPM system under environmental excitations. The three scenarios in study are as follows:the SPM is under the combined function of(a) wind,waves and current,(b) wind and waves,(c) current and waves. They are so set that one can compare the contributions of different types of loads in both static and dynamic studies. Numerical study shows that wind and current are the two major factors contributing to the mooring line tension,and surge and sway are the two dominant motions of the moored vessel subjected to environmental excitations. 相似文献
11.
It is generally believed that the equilibrium range of wind wave spectrum is in the form of the −4 rather than −5 power law.
However, in the widely applied P-M spectrum the equilibrium range is given in the form of −5 power law. In the present paper,
a spectrum for full development of wind waves is proposed using the form of the Neumann spectrum, but adopting the −4 power
law for the equilibrium range. The proposed spectrum has been verified with NDBC buoy data and could be a substitute for the
P-M spectrum. 相似文献
12.
Combining the 3/2 power law proposed by Toba with the significant wave energy balance equation for wind waves, wave growth
in deep water for short fetch is investigated. It is found that the variations of wave height and period with fetch have the
form of power function with fractional exponents 3/8 and 1/4 respectively. Using these exponents in the power functions and
through data fitting, the concise wind wave growth relations for short fetch are obtained. 相似文献
13.
LIU Yuguang ) * YAN Xiao-Hai ) SU Ming-Yang ) ) Physical Oceanography Laboratory College of Marine Environment Ocean University of China Qingdao P..R.China) Center for Remote Sensing Graduate College of Marine Studies University of Delaware Newark DE USA ) Oceanography Division Naval Research Laboratory Stennis Space Center MS USA 《中国海洋大学学报(英文版)》2003,2(1)
1 Introduction1.1 Proposed ModelonDirectionalFrequencySpec trum ThisisthePartⅡofthetwo papersetondirection alspectraofwindwaves.Anewmodelonthedirec tionalspectrumofwindwavesfordeepwaterispro posedbasedonthestatisticsofwindwavesinthePartⅠ .Substituting (4 5 )ofPartⅠinto (4 0 )andaddingapeak enhancementitemγΓ,weobtainS(ω ,) =0 .0 0 93αaαwD( ,k) ωpω2 ξ- 4g2ω5×exp - 2 ξ+14[bωp +(1-b)ωp]4ω4 γΓ. (1)Here ,αaisthewaveagefactorofspectralcoefficientdefinedbyαa = ω0 .55… 相似文献
14.
In this study, we developed the first linear Joint North Sea Wave Project (JONSWAP) spectrum (JS), which involves a transformation from the JS solution to the natural logarithmic scale. This transformation is convenient for defining the least squares function in terms of the scale and shape parameters. We identified these two wind-dependent parameters to better understand the wind effect on surface waves. Due to its efficiency and high-resolution, we employed the airborne Light Detection and Ranging (LIDAR) system for our measurements. Due to the lack of actual data, we simulated ocean waves in the MATLAB environment, which can be easily translated into industrial programming language. We utilized the Longuet-Higgin (LH) random-phase method to generate the time series of wave records and used the fast Fourier transform (FFT) technique to compute the power spectra density. After validating these procedures, we identified the JS parameters by minimizing the mean-square error of the target spectrum to that of the estimated spectrum obtained by FFT. We determined that the estimation error is relative to the amount of available wave record data. Finally, we found the inverse computation of wind factors (wind speed and wind fetch length) to be robust and sufficiently precise for wave forecasting. 相似文献
15.
Study on the growth of wind wave frequency spectra generated by cold waves in the northern East China Sea 总被引：1，自引：0，他引：1
The growth of frequency spectra and spectral parameters of wind waves generated by cold waves, a kind of severe weather system, in the northern East China Sea is studied in this paper. Based on a third-generation wave action model(the Simulating WAves Nearshore model), simulations were developed to analyze the spatiotemporal characteristics of wind waves and to output spectral data. It is shown that the cold wave-induced spectra can be well described by the modified Joint North Sea Wave Project spectral form. The growth of wave spectra is comprehensively reflected by the evolution of the three characteristic parameters: peak frequency, spectral peak and wave energy. Besides, the approximations of dependences between spectral parameters and the three types of universal induced factors are obtained with the least squares method and compared systematically. Fetch and peak frequency turn out to be suitable parameters to describe the spectral parameters, while the dependences on the inverse wave age vary in different sea areas. In general, the derived relationships improve on results from previous studies for better practical application of the wind wave frequency spectrum in the northern East China Sea. 相似文献
16.
A new model on the directional spectrum of wind waves for deep water is proposed based on the statistics of wind waves. This
model contains three parameters: the wave age, the inverse spectral bandwidth and the local spectral-peak angular frequency.
The inverse spectral bandwidth is a robust parameter for describing the spectral steepness of wind waves. Using the inverse
spectral bandwidth parameter, the proposed model can well describe various observations obtained from the open ocean and laboratory
tank. 相似文献
17.
LIU Yuguang ) * YAN Xiao-Hai ) SU Ming-Yang ) ) Physical Oceanography Laboratory College of Marine Environment Ocean University of China Qingdao P..R.China) Center for Remote Sensing Graduate College of Marine Studies University of Delaware Newark DE USA) Oceanography Division Naval Research Laboratory Stennis Space Center MS USA 《中国海洋大学学报(英文版)》2003,2(1)
1 Introduction Numerousinvestigationsondeepwaterwindwavespectrumhavebeen performed (Phillips ,195 8;Bretschneider,195 9;PiersonandMoscowitz ,196 4;Hasselmannetal.,1973;Donelanetal.,1985 ;Ban ner ,1990 ;Wenetal.,1999) .Ondimensionalground ,Phillips (195 8)suggestedthattheequilibriumfre quencyspectrumofwindwavesfordeepwatershouldbe proportionaltoω- 5,andthecorrespondingwavenumberspectrumshouldbe proportionaltok- 4,whereωistheangularfrequencyandkisthewavenumber.Forfully developedwindwaves… 相似文献
18.
Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to
represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models
of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the
slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber
models and using the dispersion relation of water surface waves, we derive the slope wavenumber spectrum models of capillary
and capillary-gravity waves. Simultaneously, by using the slope wavenumber models, the dependence of the slope wavenumber
spectrum on wind speed is analyzed using data obtained in an experiment which was performed in a laboratory wind wave tank.
Generally speaking, the slope wavenumber spectra are influenced profoundly by the wind speed above water surface. The slope
wavenumber spectrum increases with wind speed obviously and do not cross each other for different wind speeds. But, for the
same wind speed, the slope wavenumber spectra are essentially identical, even though the capillary and capillary-gravity waves
are excited at different times and locations. Furthermore, the slope wavenumber spectra obtained from the models agree quite
well with experimental results as regards both the values and the shape of the curve. 相似文献
19.
《中国海洋湖沼学报》2019,(6)
In this study, typhoon waves generated during three typhoons(Damrey(1210), Fung-wong(1416), and Chan-hom(1509)) in the Yellow Sea and East China Sea were simulated in a simulating waves nearshore(SWAN) model, and the wind forcing was constructed by combining reanalyzed wind data with a Holland typhoon wind model. Various parameters, such as the Holland fitting parameter(B) and the maximum wind radius(R), were investigated in sensitivity experiments in the Holland model that affect the wind field construction. Six different formulations were considered and the parameters determined by comparing the simulated wind results with in-situ wind measurements. The key factors affecting wave growth and dissipation processes from deep to shallow waters were studied, including wind input, whitecapping, and bottom friction. Comparison with in-situ wave measurements suggested that the KOMEN scheme(wind input exponential growth and whitecapping energy dissipation) and the JONSWAP scheme(dissipation of bottom friction) resulted in good reproduction of the significant wave height of typhoon waves. A preliminary analysis of the wave characteristics in terms of wind-sea and swell wave revealed that swell waves dominated with the distance of R to the eye of the typhoon, while wind-sea prevailed in the outer region up to six to eight times the R values despite a clear misalignment between wind and waves. The results support the hypothesis that nonlinear wave-wave interactions may play a key role in the formation of wave characteristics. 相似文献