An empirical formula for estimating the overtopping discharge of wind-waves on a smooth-impermeable-simple slope dyke is derived through model tests in this paper, it can be adopted by related design departments in th...An empirical formula for estimating the overtopping discharge of wind-waves on a smooth-impermeable-simple slope dyke is derived through model tests in this paper, it can be adopted by related design departments in the determination of the crest elevation of the dyke.展开更多
Spectral characteristics of wind-generated waves in labortaory are presented on the basis of a systematic measurement in a large-scale wind-wave channel and compared with those in the field. A marked characteristics o...Spectral characteristics of wind-generated waves in labortaory are presented on the basis of a systematic measurement in a large-scale wind-wave channel and compared with those in the field. A marked characteristics of the measured spetra is the existence of secondary spectrum-peak. The dependence of spectral peak-frequency, peak-value and zeroth-order moment on wind speed and fetch are presented and found roughly similar to those in the field represented by the JONSWAP spectrum, regardless of the differences in coefficient. The spectral slope beta at high-frequencies are found somewhat greater than those of field wind-waves in both cases of deep and shallow waters. Except for the low-frequency part, the spectral forms measured in different wind conditions are similar and fit for the JONSWAP spectrum with gamma = 6 and beta = 5.5. Some relevant problems are discussed.展开更多
The spectrum variance m0, peak frequency ω0 and peakness factor p are expressed in terms of nondimensional fetch and duration by making use of relations which are derived through comparing and analyzing existing empi...The spectrum variance m0, peak frequency ω0 and peakness factor p are expressed in terms of nondimensional fetch and duration by making use of relations which are derived through comparing and analyzing existing empirical formulas for the growth of significant wave height and period. The main features of spectrum growth as specified by these parameters agree with those of the JONS-WAP experiments. For given wind speed and fetch, the high frequency parts beyond the peaks of shallow water spectra almost coincide with that of the corresponding deep water spectrum, whereas the low frequency parts differ appreciably. The method developed in this paper predicts smaller significant wave height as well as smaller wave period for shallow water spectra in contrast to the theoretical result of Kitaigorodskii ef al, in which the peak frequency, and consequently the significant wave period, remains basically unchanged for different water depths. Spectra are further reduced to a form in which only significant wave height and period are left as parameters, the peakness factor being replaced by the wave steepness through an empirical relation between them. Spectra in this form have been verified by observations.展开更多
Results of drag coefficient（CD） from field observations and laboratory wave tank experiments indicate that the operational wave model can overestimate wind energy input under high wind conditions. The wind-wave inte...Results of drag coefficient（CD） from field observations and laboratory wave tank experiments indicate that the operational wave model can overestimate wind energy input under high wind conditions. The wind-wave interaction source term in WAVEWATCH Ⅲ has been modified to examine its behavior with tropical cyclone wind forcing. Using high resolution wind input,numerical experiments under idealized wind field and tropical cyclone Bonnie（1998） were designed to evaluate performance of the modified models. Both experiments indicate that the modified models with reduced CD significantly decrease wind energy input into the wave model and then simulate lower significant wave height（SWH） than the original model. However,the effects on spatial distribution of SWH,mean wavelength,mean wave direction,and directional wave spectra are insignificant. Due to the reduced wind energy input,the idealized experiment shows that the modified models simulate lower SWH than the original model in all four quadrants. The decrease in the front quadrants is significantly larger than that in the rear quadrants;it is larger under higher winds than lower winds. The realistic experiment on tropical cyclone Bonnie shows that the modified model with the various downward trends of CD in high winds creates a simulation that agrees best with scanning radar altimeter observations.展开更多
The relationships between sea surface roughness z 0 and wind-wave parameters are analyzed,and spurious self-correlations are found in all of the parameterization schemes.Sea surface drag coefficient C D is fitted by f...The relationships between sea surface roughness z 0 and wind-wave parameters are analyzed,and spurious self-correlations are found in all of the parameterization schemes.Sea surface drag coefficient C D is fitted by four wind-wave parameters that are wave age,wave steepness,windsea Reynolds number R B and R H ,and the analyzed data are divided into laboratory,field and combined data sets respectively.Comparison and analysis of dependence of C D on wind-wave parameters show that R B can fit the C D most appropriately.Wave age and wave steepness are not suitable to fit C D with a narrow range data set.When the value of wave age has a board range,R H is not suitable to fit C D either.Three relationships between C D and R B are integrated into the bulk algorithm COARE to calculate the observational friction velocity,and the results show that the relationship between C D and R B which is fitted with field data set can describe the momentum transfer in the open ocean,under low-moderate wind speed condition,most appropriately.展开更多
A directional function for frequencies equal to and larger than the peak frequency of a wind-wave frequency spectrum is constructed by fitting the angular spreading based on the analytically derived directional spectr...A directional function for frequencies equal to and larger than the peak frequency of a wind-wave frequency spectrum is constructed by fitting the angular spreading based on the analytically derived directional spectrum of Wen et al. (1993, Journal of Oceanography, 49(2), 131～147, 149～172). For frequencies smaller than the peak frequency, the directional function is obtained by comparing and analyzing existing formulas. The nondimensional wind-wave frequency spectrum of Wen et al. (1994, Progress in Natural Seience, 4(4). 407～427;4 (5), 586～596) has been used together with the directional function just mentioned to obtain the directional spectrum for easier application.展开更多
Wen et al.'s method developed to obtain wind-wave frequency spectrum in deep water was used to derive the spectrum in finite depth water. The spectrum S(ω) (ω being angular frequency) when normalized with the ze...Wen et al.'s method developed to obtain wind-wave frequency spectrum in deep water was used to derive the spectrum in finite depth water. The spectrum S(ω) (ω being angular frequency) when normalized with the zeroth moment m0 and peak frequency ω0, contains in addition to the peakness factor P= ω0S(ω0)/m0, a depth parameter ω= (2πm0)1/2/d (d being water depth), so the spectrum behavior can be studied for different wave growth stages and water depths.展开更多
The spectrum derived in Part 1 of the presert paper is here systematically verified with field data andcompared at some length with that obtained by multiplying the deep-water spectrum with theKitaigorodskii factor.
Most wind turbine blades are assembled piece-by-piece onto the hub of a monopile-type offshore wind turbine using jack-up crane vessels.Despite the stable foundation of the lifting cranes,the mating process exhibits s...Most wind turbine blades are assembled piece-by-piece onto the hub of a monopile-type offshore wind turbine using jack-up crane vessels.Despite the stable foundation of the lifting cranes,the mating process exhibits substantial relative responses amidst blade root and hub.These relative motions are combined effects of wave-induced monopile motions and wind-induced blade root motions,which can cause impact loads at the blade root’s guide pin in the course of alignment procedure.Environmental parameters including the wind-wave misalignments play an important role for the safety of the installation tasks and govern the impact scenarios.The present study investigates the effects of wind-wave misalignments on the blade root mating process on a monopile-type offshore wind turbine.The dynamic responses including the impact velocities between root and hub in selected wind-wave misalignment conditions are investigated using multibody simulations.Furthermore,based on a finite element study,different impact-induced failure modes at the blade root for sideways and head-on impact scenarios,developed due to wind-wave misalignment conditions,are investigated.Finally,based on extreme value analyses of critical responses,safe domain for the mating task under different wind-wave misalignments is compared.The results show that although misaligned wind-wave conditions develop substantial relative motions between root and hub,aligned wind-wave conditions induce largest impact velocities and develop critical failure modes at a relatively low threshold velocity of impact.展开更多
Sea spray induced by surface wave breaking plays an important role in air-sea flux.However,large differences in sea spray generation at the same wind speed were presented in previous studies.As a result,the parameteri...Sea spray induced by surface wave breaking plays an important role in air-sea flux.However,large differences in sea spray generation at the same wind speed were presented in previous studies.As a result,the parameterizations of sea spray generation functions can reach 4 orders difference.Wind speed may not be enough to explain this difference,and the surface wave state is a significant factor that causes this large difference,which then affects the estimation of the air-sea heat fluxes.In this study,synchronous observations of air-sea heat fluxes,surface waves and sea spray were conducted at a tower-based platform in a coastal region.Results showed that the sea spray generation is strongly correlated with both wind speed,and wave age as previously;more importantly,wind-wave alignment angle can cause approximately 1.3 orders(or 20 times)of sea spray generation function(SSGF)difference.A new SSGF with a dimensionless parameter RB0.7β-1cosθwas proposed.Heat fluxes caused by sea spray can be comparable to interfacial heat fluxes even at moderate wind speed.The three parameters of sea spray(α=6.4,σ=16,γ=6.3)were optimally fitted and evaluated.The air-sea heat flux evaluated in droplet evaporation layer(DEL)was improved with the new scheme,especially for sensible heat flux.The new parameters should be more suitable than other widely used parameters in numerical simulations.展开更多
Wind input parameterizations proposed by Jeffreys, Sverdrup and Munk, and Plant are analyzed. It is found by analogy that the similarity of integrals of the three wind input parameterizations exists. Wave breaking dis...Wind input parameterizations proposed by Jeffreys, Sverdrup and Munk, and Plant are analyzed. It is found by analogy that the similarity of integrals of the three wind input parameterizations exists. Wave breaking dissipation parameterizations proposed by Tsikunov, Hasselmann, and Phillips are also analyzed. Likewise it is found by analogy that the similarity of integrals of the three dissipation parameterizations exists. The similarities of wind input and dissipation are applied to the investigation of the fetch-limited growth of wind waves, together with the 3/2 power law presented by Toba. Some semi-empirical formulas concerning the growth of wave height and period with fetch are presented. The results from the formulas are in good agreement with previous field observations.展开更多
Numerical modeling of sea states has been developed for years,and used for varied fields such as coastal work sizing,navigation safety,beaches and water leisure stability study.The third-generation ocean wind-wave spe...Numerical modeling of sea states has been developed for years,and used for varied fields such as coastal work sizing,navigation safety,beaches and water leisure stability study.The third-generation ocean wind-wave spectral model WAVEWATCH III(WW3)software was adopted and developed to simulate wave propagation in the Mediterranean basin.In this work,a more detailed study was carried out on the port of Algiers.Two different atmospheric models have been used to get the wind forcing:ALADIN(Area Limited Dynamic Adaptation Inter National Development)with an 8 km resolution.And AROME(Application to Operational Research at Meso-scale)with a 3 km resolution.The results obtained using both of the atmospheric models have been compared and analyzed.展开更多
Considering the large diameter effect of piles,the influence of different pile-soil analysis methods on the design of monopile foundations for offshore wind turbines has become an urgent problem to be solved.Three dif...Considering the large diameter effect of piles,the influence of different pile-soil analysis methods on the design of monopile foundations for offshore wind turbines has become an urgent problem to be solved.Three different pile-soil models were used to study a large 10 MW monopile wind turbine.By modeling the three models in the SACS software,this paper analyzed the motion response of the overall structure under the conditions of wind and waves.According to the given working conditions,this paper concludes that under the condition of independent wind,the average value of the tower top x-displacement of the rigid connection method is the smalle st,and the standard deviation is the smallest under the condition of independent wave.The results obtained by the p-y curve method are the most conservative.展开更多
In this paper, the observational data from Marine and Meteorological Observation Platform （MMOP） at Bohe, Maoming and buoys located in Shanwei and Maoming are used to study the characteristics of air-sea temperature...In this paper, the observational data from Marine and Meteorological Observation Platform （MMOP） at Bohe, Maoming and buoys located in Shanwei and Maoming are used to study the characteristics of air-sea temperature and specific humidity difference and the relationship between wind and wave with the tropical cyclones over the South China Sea （SCS）. The heat and momentum fluxes from eddy covariance measurement （EC） are compared with these fluxes calculated by the COARE 3.0 algorithm for Typhoon Koppu. The results show that at the developing and weakening stages of Koppu, both these differences between the sea surface and the near-surface atmosphere from the MMOP are negative, and data from the buoys also indicate that the differences are negative between the sea surface and near-surface atmosphere on the right rear portion of tropical cyclones （TCs） Molave and Chanthu. However, the differences are positive on the left fi＇ont portion of Molave and Chanthu. These positive differences suggest that the heat flux is transferred from the ocean to the atmosphere, thus intensifying and maintaining the two TCs. The negative differences indicate that the ocean removes heat fluxes from the atmosphere, thus weakening the TCs. The wind-wave curves of TCs Molave and Chanthu show that significant wave height increases linearly with 2-min wind speed at 10-m height when the wind speed is less than 25 m/s, but when the wind speed is greater than 25 m/s, the significant wave height increases slightly with the wind speed. By comparing the observed sensible heat, latent heat, and friction velocity from EC with these variables from COARE 3.0 algorithm, a great bias between the observed and calculated sensible heat and latent heat fluxes is revealed, and the observed friction velocity is found to be almost the same as the calculated friction velocity.展开更多
Marine renewable energy,combining wave energy converters(WECs)and floating wind turbines(FWTs)into hybrid wave-wind energy converters(HWWECs),garners significant global interest.HWWECs offer potential cost reductions,...Marine renewable energy,combining wave energy converters(WECs)and floating wind turbines(FWTs)into hybrid wave-wind energy converters(HWWECs),garners significant global interest.HWWECs offer potential cost reductions,increased power generation,and enhanced system stability.The absorption power of high wind energy sites is primarily influenced by the complex hydrodynamic interactions among floating bodies,which are closely related to the location and wind-wave environment of high wind energy sites.To delve into the positive interactions among HWWECs,this paper proposes a HWWEC array optimization strategy based on the artificial ecosystem opti-mization-manta ray foraging optimization coordinated optimizer(EMCO).In EMCO,the decomposition operator of artificial ecosystem optimization(AEO)and the flipping-dipper foraging operator of manta ray foraging optimization coordinated(MRFO)cooperate dynamically to effectively balance local exploitation and global exploration.To validate the effectiveness of EMCO,experiments were conducted in scenarios with 3,5,8,and 20 HWWECs,and compared with five typical algorithms.Experimental results demonstrate the existence of multiple optimal solutions for HWWEC arrays.EMCO achieves maximum total absorp-tion power and exhibits good stability.Notably,EMCO en-hances the q-factor values of HWWECs across four scales:1.0478,1.0586,1.0612,and 0.9965,respectively.展开更多
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 powe...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.展开更多
According to the wind-wave individual case directional spectra obtained from the instrument array and'956' wave buoy measures, the wind-wave directional spectra presented by Mitsuyasu, Donelan and Hasselmann o...According to the wind-wave individual case directional spectra obtained from the instrument array and'956' wave buoy measures, the wind-wave directional spectra presented by Mitsuyasu, Donelan and Hasselmann onthe basis of the observations as well as theoretical wind-wave directional spectra by Wen Shengchang on the basis ofanalytic method are compared and checked from the pointview of total energy. Results show that Mitsuyasu's directional spectra are well identical with the measured wind-wave directional spectra developing fully in the Bohai Sea.Donelan's and theoretical wind-wave directional spectra are also quite consistent with the measured results in the development of the wind waves, especially best with the measured results in the initial stage of the development of thewind waves.展开更多
This paper provides the calculation formulas used to circulate the atmosphere,including the horizontal type of wind speed equation,the vertical type of wind speed equation,the circulation cyclone,and an example.The re...This paper provides the calculation formulas used to circulate the atmosphere,including the horizontal type of wind speed equation,the vertical type of wind speed equation,the circulation cyclone,and an example.The results have been used for disaster-linked problems,including“new way of solving Naiver—Stokes equation”and“Air Crash and Pressure”.The goal of this paper is to show the work of a certain type.The solution of a certain type can be expressed by formulas.Formulas are the value of this paper.展开更多
Despite their importance in the ocean environment,the key physical processes in wind-wave interactions are poorly understood.Using a solver developed for undulatory boundaries,we perform numerical simulations of the w...Despite their importance in the ocean environment,the key physical processes in wind-wave interactions are poorly understood.Using a solver developed for undulatory boundaries,we perform numerical simulations of the wind-wave system under various sea conditions,including wind over monochromatic waves,early wind-wave generation,and wind over a broadband wave field.Our results show that the wave direction and wave age can significantly change the distribution of streamwise vorticity in the wind field.Different wave patterns are observed in the process of wind-wave generation.In a broadband wave field,the wave growth rate due to wind input is found to depend on the wave steepness.展开更多
Based on Tian et al. ＇s theoretical model of microwave scattering, by using the wind wave spectrum suggested by Fung et al. , numerical results of polarized back-scattering were calculated. The quantitative relations...Based on Tian et al. ＇s theoretical model of microwave scattering, by using the wind wave spectrum suggested by Fung et al. , numerical results of polarized back-scattering were calculated. The quantitative relationships between the calculated backscattering cross section and the environmental parameters, such as wind speeds, azimuthal angles and incidence angles, were studied. Compared with the traditional two-scale scattering model, the results are much more coincident with the observations under the condition of moderate incidence angles, which is very useful to make up for the two-scale model. To make the new calculation model to be used conveniently in the practice, its simplified form was proposed.展开更多
文摘An empirical formula for estimating the overtopping discharge of wind-waves on a smooth-impermeable-simple slope dyke is derived through model tests in this paper, it can be adopted by related design departments in the determination of the crest elevation of the dyke.
基金This work was financially supported by the National Science Foundation of China(No.4967277)
文摘Spectral characteristics of wind-generated waves in labortaory are presented on the basis of a systematic measurement in a large-scale wind-wave channel and compared with those in the field. A marked characteristics of the measured spetra is the existence of secondary spectrum-peak. The dependence of spectral peak-frequency, peak-value and zeroth-order moment on wind speed and fetch are presented and found roughly similar to those in the field represented by the JONSWAP spectrum, regardless of the differences in coefficient. The spectral slope beta at high-frequencies are found somewhat greater than those of field wind-waves in both cases of deep and shallow waters. Except for the low-frequency part, the spectral forms measured in different wind conditions are similar and fit for the JONSWAP spectrum with gamma = 6 and beta = 5.5. Some relevant problems are discussed.
文摘The spectrum variance m0, peak frequency ω0 and peakness factor p are expressed in terms of nondimensional fetch and duration by making use of relations which are derived through comparing and analyzing existing empirical formulas for the growth of significant wave height and period. The main features of spectrum growth as specified by these parameters agree with those of the JONS-WAP experiments. For given wind speed and fetch, the high frequency parts beyond the peaks of shallow water spectra almost coincide with that of the corresponding deep water spectrum, whereas the low frequency parts differ appreciably. The method developed in this paper predicts smaller significant wave height as well as smaller wave period for shallow water spectra in contrast to the theoretical result of Kitaigorodskii ef al, in which the peak frequency, and consequently the significant wave period, remains basically unchanged for different water depths. Spectra are further reduced to a form in which only significant wave height and period are left as parameters, the peakness factor being replaced by the wave steepness through an empirical relation between them. Spectra in this form have been verified by observations.
基金The National Natural Science Foundation of China under contract No. 40706008the Open Research Program of the Key Laboratory of Chinese Acadeing of Sciences for Tropical Marine Environmental Dynamics under contract No. LED0606+1 种基金the Shandong Province Natural Science Foundation of China under contract No. Z2008E02the National High Technology Research and Development Program ("863" Program) of China under contract No. 2008AA09A402
文摘Results of drag coefficient（CD） from field observations and laboratory wave tank experiments indicate that the operational wave model can overestimate wind energy input under high wind conditions. The wind-wave interaction source term in WAVEWATCH Ⅲ has been modified to examine its behavior with tropical cyclone wind forcing. Using high resolution wind input,numerical experiments under idealized wind field and tropical cyclone Bonnie（1998） were designed to evaluate performance of the modified models. Both experiments indicate that the modified models with reduced CD significantly decrease wind energy input into the wave model and then simulate lower significant wave height（SWH） than the original model. However,the effects on spatial distribution of SWH,mean wavelength,mean wave direction,and directional wave spectra are insignificant. Due to the reduced wind energy input,the idealized experiment shows that the modified models simulate lower SWH than the original model in all four quadrants. The decrease in the front quadrants is significantly larger than that in the rear quadrants;it is larger under higher winds than lower winds. The realistic experiment on tropical cyclone Bonnie shows that the modified model with the various downward trends of CD in high winds creates a simulation that agrees best with scanning radar altimeter observations.
基金The National Natural Science Foundation of China under Grant Nos 40675056 41076074National Key Basic Research Development Program under Grant No.2007CB411805the Basic Theory Foundation of Institute of Meteorology, PLA University of Science and Technology
文摘The relationships between sea surface roughness z 0 and wind-wave parameters are analyzed,and spurious self-correlations are found in all of the parameterization schemes.Sea surface drag coefficient C D is fitted by four wind-wave parameters that are wave age,wave steepness,windsea Reynolds number R B and R H ,and the analyzed data are divided into laboratory,field and combined data sets respectively.Comparison and analysis of dependence of C D on wind-wave parameters show that R B can fit the C D most appropriately.Wave age and wave steepness are not suitable to fit C D with a narrow range data set.When the value of wave age has a board range,R H is not suitable to fit C D either.Three relationships between C D and R B are integrated into the bulk algorithm COARE to calculate the observational friction velocity,and the results show that the relationship between C D and R B which is fitted with field data set can describe the momentum transfer in the open ocean,under low-moderate wind speed condition,most appropriately.
文摘A directional function for frequencies equal to and larger than the peak frequency of a wind-wave frequency spectrum is constructed by fitting the angular spreading based on the analytically derived directional spectrum of Wen et al. (1993, Journal of Oceanography, 49(2), 131～147, 149～172). For frequencies smaller than the peak frequency, the directional function is obtained by comparing and analyzing existing formulas. The nondimensional wind-wave frequency spectrum of Wen et al. (1994, Progress in Natural Seience, 4(4). 407～427;4 (5), 586～596) has been used together with the directional function just mentioned to obtain the directional spectrum for easier application.
基金Project supported by the National Natural Science Foundation of China.
文摘Wen et al.'s method developed to obtain wind-wave frequency spectrum in deep water was used to derive the spectrum in finite depth water. The spectrum S(ω) (ω being angular frequency) when normalized with the zeroth moment m0 and peak frequency ω0, contains in addition to the peakness factor P= ω0S(ω0)/m0, a depth parameter ω= (2πm0)1/2/d (d being water depth), so the spectrum behavior can be studied for different wave growth stages and water depths.
基金Project supported by the National Natural Science Foundation of China.
文摘The spectrum derived in Part 1 of the presert paper is here systematically verified with field data andcompared at some length with that obtained by multiplying the deep-water spectrum with theKitaigorodskii factor.
基金The study is a part of SFI MOVE projects funded by the Research Council of Norway,NFR project number 237929.
文摘Most wind turbine blades are assembled piece-by-piece onto the hub of a monopile-type offshore wind turbine using jack-up crane vessels.Despite the stable foundation of the lifting cranes,the mating process exhibits substantial relative responses amidst blade root and hub.These relative motions are combined effects of wave-induced monopile motions and wind-induced blade root motions,which can cause impact loads at the blade root’s guide pin in the course of alignment procedure.Environmental parameters including the wind-wave misalignments play an important role for the safety of the installation tasks and govern the impact scenarios.The present study investigates the effects of wind-wave misalignments on the blade root mating process on a monopile-type offshore wind turbine.The dynamic responses including the impact velocities between root and hub in selected wind-wave misalignment conditions are investigated using multibody simulations.Furthermore,based on a finite element study,different impact-induced failure modes at the blade root for sideways and head-on impact scenarios,developed due to wind-wave misalignment conditions,are investigated.Finally,based on extreme value analyses of critical responses,safe domain for the mating task under different wind-wave misalignments is compared.The results show that although misaligned wind-wave conditions develop substantial relative motions between root and hub,aligned wind-wave conditions induce largest impact velocities and develop critical failure modes at a relatively low threshold velocity of impact.
基金supported by the National Natural Science Foundation of China(Grant Nos.42276024,42076014)the Basic Scientific Fund for National Public Research Institutes of China(Grant No.2024S02)。
文摘Sea spray induced by surface wave breaking plays an important role in air-sea flux.However,large differences in sea spray generation at the same wind speed were presented in previous studies.As a result,the parameterizations of sea spray generation functions can reach 4 orders difference.Wind speed may not be enough to explain this difference,and the surface wave state is a significant factor that causes this large difference,which then affects the estimation of the air-sea heat fluxes.In this study,synchronous observations of air-sea heat fluxes,surface waves and sea spray were conducted at a tower-based platform in a coastal region.Results showed that the sea spray generation is strongly correlated with both wind speed,and wave age as previously;more importantly,wind-wave alignment angle can cause approximately 1.3 orders(or 20 times)of sea spray generation function(SSGF)difference.A new SSGF with a dimensionless parameter RB0.7β-1cosθwas proposed.Heat fluxes caused by sea spray can be comparable to interfacial heat fluxes even at moderate wind speed.The three parameters of sea spray(α=6.4,σ=16,γ=6.3)were optimally fitted and evaluated.The air-sea heat flux evaluated in droplet evaporation layer(DEL)was improved with the new scheme,especially for sensible heat flux.The new parameters should be more suitable than other widely used parameters in numerical simulations.
文摘Wind input parameterizations proposed by Jeffreys, Sverdrup and Munk, and Plant are analyzed. It is found by analogy that the similarity of integrals of the three wind input parameterizations exists. Wave breaking dissipation parameterizations proposed by Tsikunov, Hasselmann, and Phillips are also analyzed. Likewise it is found by analogy that the similarity of integrals of the three dissipation parameterizations exists. The similarities of wind input and dissipation are applied to the investigation of the fetch-limited growth of wind waves, together with the 3/2 power law presented by Toba. Some semi-empirical formulas concerning the growth of wave height and period with fetch are presented. The results from the formulas are in good agreement with previous field observations.
文摘Numerical modeling of sea states has been developed for years,and used for varied fields such as coastal work sizing,navigation safety,beaches and water leisure stability study.The third-generation ocean wind-wave spectral model WAVEWATCH III(WW3)software was adopted and developed to simulate wave propagation in the Mediterranean basin.In this work,a more detailed study was carried out on the port of Algiers.Two different atmospheric models have been used to get the wind forcing:ALADIN(Area Limited Dynamic Adaptation Inter National Development)with an 8 km resolution.And AROME(Application to Operational Research at Meso-scale)with a 3 km resolution.The results obtained using both of the atmospheric models have been compared and analyzed.
基金financially supported by the Open Research Fund of Hunan Provincial Key Laboratory of Key Technology on Hydropower Development (Grant No.PKLHD202003)the National Natural Science Foundation of China (Grant Nos.52071058 and 51939002)+1 种基金the National Natural Science Foundation of Liaoning Province (Grant No.2022-KF-18-01)Fundamental Research Funds for the Central University (Grant No.DUT20ZD219)。
文摘Considering the large diameter effect of piles,the influence of different pile-soil analysis methods on the design of monopile foundations for offshore wind turbines has become an urgent problem to be solved.Three different pile-soil models were used to study a large 10 MW monopile wind turbine.By modeling the three models in the SACS software,this paper analyzed the motion response of the overall structure under the conditions of wind and waves.According to the given working conditions,this paper concludes that under the condition of independent wind,the average value of the tower top x-displacement of the rigid connection method is the smalle st,and the standard deviation is the smallest under the condition of independent wave.The results obtained by the p-y curve method are the most conservative.
基金Key Project of Natural Science Foundation of China(40730948)National Basic Research Program of China(2009CB421501)National Natural Science Foundation of China(41075051)
文摘In this paper, the observational data from Marine and Meteorological Observation Platform （MMOP） at Bohe, Maoming and buoys located in Shanwei and Maoming are used to study the characteristics of air-sea temperature and specific humidity difference and the relationship between wind and wave with the tropical cyclones over the South China Sea （SCS）. The heat and momentum fluxes from eddy covariance measurement （EC） are compared with these fluxes calculated by the COARE 3.0 algorithm for Typhoon Koppu. The results show that at the developing and weakening stages of Koppu, both these differences between the sea surface and the near-surface atmosphere from the MMOP are negative, and data from the buoys also indicate that the differences are negative between the sea surface and near-surface atmosphere on the right rear portion of tropical cyclones （TCs） Molave and Chanthu. However, the differences are positive on the left fi＇ont portion of Molave and Chanthu. These positive differences suggest that the heat flux is transferred from the ocean to the atmosphere, thus intensifying and maintaining the two TCs. The negative differences indicate that the ocean removes heat fluxes from the atmosphere, thus weakening the TCs. The wind-wave curves of TCs Molave and Chanthu show that significant wave height increases linearly with 2-min wind speed at 10-m height when the wind speed is less than 25 m/s, but when the wind speed is greater than 25 m/s, the significant wave height increases slightly with the wind speed. By comparing the observed sensible heat, latent heat, and friction velocity from EC with these variables from COARE 3.0 algorithm, a great bias between the observed and calculated sensible heat and latent heat fluxes is revealed, and the observed friction velocity is found to be almost the same as the calculated friction velocity.
基金supported by the National Natural Science Foundation of China(No.61963020 and No.62263014)Yunnan Provincial Basic Research Project(No.202201AT070857).
文摘Marine renewable energy,combining wave energy converters(WECs)and floating wind turbines(FWTs)into hybrid wave-wind energy converters(HWWECs),garners significant global interest.HWWECs offer potential cost reductions,increased power generation,and enhanced system stability.The absorption power of high wind energy sites is primarily influenced by the complex hydrodynamic interactions among floating bodies,which are closely related to the location and wind-wave environment of high wind energy sites.To delve into the positive interactions among HWWECs,this paper proposes a HWWEC array optimization strategy based on the artificial ecosystem opti-mization-manta ray foraging optimization coordinated optimizer(EMCO).In EMCO,the decomposition operator of artificial ecosystem optimization(AEO)and the flipping-dipper foraging operator of manta ray foraging optimization coordinated(MRFO)cooperate dynamically to effectively balance local exploitation and global exploration.To validate the effectiveness of EMCO,experiments were conducted in scenarios with 3,5,8,and 20 HWWECs,and compared with five typical algorithms.Experimental results demonstrate the existence of multiple optimal solutions for HWWEC arrays.EMCO achieves maximum total absorp-tion power and exhibits good stability.Notably,EMCO en-hances the q-factor values of HWWECs across four scales:1.0478,1.0586,1.0612,and 0.9965,respectively.
基金the National Natural Science Foundation of China (40830959)the Ministry of Science and Technology of China (2011BAC03B01)
文摘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.
文摘According to the wind-wave individual case directional spectra obtained from the instrument array and'956' wave buoy measures, the wind-wave directional spectra presented by Mitsuyasu, Donelan and Hasselmann onthe basis of the observations as well as theoretical wind-wave directional spectra by Wen Shengchang on the basis ofanalytic method are compared and checked from the pointview of total energy. Results show that Mitsuyasu's directional spectra are well identical with the measured wind-wave directional spectra developing fully in the Bohai Sea.Donelan's and theoretical wind-wave directional spectra are also quite consistent with the measured results in the development of the wind waves, especially best with the measured results in the initial stage of the development of thewind waves.
文摘This paper provides the calculation formulas used to circulate the atmosphere,including the horizontal type of wind speed equation,the vertical type of wind speed equation,the circulation cyclone,and an example.The results have been used for disaster-linked problems,including“new way of solving Naiver—Stokes equation”and“Air Crash and Pressure”.The goal of this paper is to show the work of a certain type.The solution of a certain type can be expressed by formulas.Formulas are the value of this paper.
文摘Despite their importance in the ocean environment,the key physical processes in wind-wave interactions are poorly understood.Using a solver developed for undulatory boundaries,we perform numerical simulations of the wind-wave system under various sea conditions,including wind over monochromatic waves,early wind-wave generation,and wind over a broadband wave field.Our results show that the wave direction and wave age can significantly change the distribution of streamwise vorticity in the wind field.Different wave patterns are observed in the process of wind-wave generation.In a broadband wave field,the wave growth rate due to wind input is found to depend on the wave steepness.
文摘Based on Tian et al. ＇s theoretical model of microwave scattering, by using the wind wave spectrum suggested by Fung et al. , numerical results of polarized back-scattering were calculated. The quantitative relationships between the calculated backscattering cross section and the environmental parameters, such as wind speeds, azimuthal angles and incidence angles, were studied. Compared with the traditional two-scale scattering model, the results are much more coincident with the observations under the condition of moderate incidence angles, which is very useful to make up for the two-scale model. To make the new calculation model to be used conveniently in the practice, its simplified form was proposed.
