This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-s...This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-source software Open FOAM~?, a two-dimensional viscous-flow numerical wave flume was developed to simulate the fluid resonant motions induced by transient focused wave groups with different spectral peak periods and wave amplitudes. The results indicate that for all the incident focused wave amplitudes considered, the amplitudes of the free surface elevation in the gap, horizontal wave force and moment all exhibit a bimodal variation trend with increasing spectral peak period. The peak values of the above amplitude-period curve appear near the resonant period of the first and second harmonic components of the free surface elevation. However, the variation in the vertical wave force versus the spectral peak period presents different patterns. In addition, the first-to fourth-order harmonic components in the wave surface and forces are further examined via the four-phase combination method. The results show that the first-to secondorder harmonic components play a dominant role in the overall amplitude.展开更多
The physical simulation method of wave groups in a wave flume is proposed and verified by the exper- iments. The experimental results demonstrate that random waves with desired wave groupiness, which simultaneously in...The physical simulation method of wave groups in a wave flume is proposed and verified by the exper- iments. The experimental results demonstrate that random waves with desired wave groupiness, which simultaneously includes the wave group height and length, can be generated satisfactorily at the specified position in a wave flume using the proposed method. Furthermore, the transformation properties of the wave groupiness along the fiat-bottomed wave flume are investigated based on the physically simulated waves. Associated proposals with the physical simulation of wave groups are given.展开更多
Wave group is important in ocean wave theory and applications. In the past, nonlinear interaction among wave groups has been studied on the basis of the nonlinear Sehrrdinger equation. Using this theoretical approach,...Wave group is important in ocean wave theory and applications. In the past, nonlinear interaction among wave groups has been studied on the basis of the nonlinear Sehrrdinger equation. Using this theoretical approach, we found that the nonlinear interaction among wave groups causes asymmetry in the shape of the wave envelope （steeper in the front of the curve of the envelope）. An important consequence of this asymmetry is that the highest wave in a wave group appears one individual wave length ahead of the center of the wave group. Further results show that the degree of envelope asymmetry increases with increasing spectral width and the wave steepness. This theoretical analysis has been supplemented by a systematic experimental study of wind waves. Laboratory and some open sea wave data were analyzed. The results show that the shape of the wind wave envelope of wind waves has the same asymmetry predicted by the theoretical approach. The observed degree of deformation of the envelope also increases with increasing spectral width and the wave steepness as predicted by theory. These conclusions have important ramifications for practical applications of ocean wave theory.展开更多
Real waves are multidirectional waves. In the present study, the calculation method for the wave maker driving signals for generating multidirectional wave groups in physical wave basin is proposed. Its validity is fi...Real waves are multidirectional waves. In the present study, the calculation method for the wave maker driving signals for generating multidirectional wave groups in physical wave basin is proposed. Its validity is first confirmed by a numerical model for which the incident boundary condition is determined by use of the proposed method. Then, the physical simulation of multidirectional wave groups is performed in laboratory wave basin. The experimental results show that multidirectional waves with expected wave groupiness, which includes not only its group height but also its group length, can be satisfactorily zenerated at the soecified oosition in the tphvsical wave basin.展开更多
The new distributions of the statistics of wave groups based on the maximum entropy principle are presented. The maximum entropy distributions appear to be superior to conventional distributions when applied to a limi...The new distributions of the statistics of wave groups based on the maximum entropy principle are presented. The maximum entropy distributions appear to be superior to conventional distributions when applied to a limited amount of information. Its applications to the wave group properties show the effectiveness of the maximum entropy distribution. FFF filtering method is employed to obtain the wave envelope fast and efficiently. Comparisons of both the maximum entropy distribution and the distribution of Longuet-Higgins （1984） with the laboratory wind-wave data show that the former gives a better fit.展开更多
Based on field wave data, an empirical formula of wave envelope spectrum is given in this paper. Then the methods of both numerical and physical simulation of sea wave groups with the given spectrum and groupiness par...Based on field wave data, an empirical formula of wave envelope spectrum is given in this paper. Then the methods of both numerical and physical simulation of sea wave groups with the given spectrum and groupiness parameters are suggested.展开更多
Knowledge on intermittency of wave breaking is so far limited to a few summary statistics, while the probability distribution of time interval between breaking events can provide a full view of intermittency. Based on...Knowledge on intermittency of wave breaking is so far limited to a few summary statistics, while the probability distribution of time interval between breaking events can provide a full view of intermittency. Based on a series of experiments on wind wave breaking, such probability distributions are investigated. Breaking waves within a wave group were taken as a single breaking event according to recent studies. Interval between successive wave groups with breaker is the focus of this paper. For intervals in our experiments with different fetch and wind conditions, their distributions are all skewed and weighted on small intervals. Results of Kolmogorov-Smirnov tests on time series of these intervals indicate that they all follow gamma distribution, and some are even exponential type. Average breaking-group-interval decreases with friction velocity and significant steepness until the wind is strong enough;most of them are more than 10 times the dominant wave period. Group breaking probability proposed by Babanin recently and the average number of breaking waves in wave groups are also discussed, and they are seemingly more reasonable and sensitive than traditional breaking probability defined in terms of single wave.展开更多
-The effect of wave group on wave run-up on a slope dike is mainly discussed in this paper. Two simulating methods of wave group and their applications in laboratory are introduced. Synthesizing the research results o...-The effect of wave group on wave run-up on a slope dike is mainly discussed in this paper. Two simulating methods of wave group and their applications in laboratory are introduced. Synthesizing the research results of wave run-up on a slope dike, the effect of wave group on wave run-up on a slope dike in coastal protection engineering is studied as the main point.展开更多
In this article, seven months ambient noise data and 10 events recorded at seven digital stations from the Ningxia （宁夏） regional seismic network and 5 500-t controlled source explosion data recorded by 15 temporar...In this article, seven months ambient noise data and 10 events recorded at seven digital stations from the Ningxia （宁夏） regional seismic network and 5 500-t controlled source explosion data recorded by 15 temporary and 7 permanent seismic stations are used to measure dispersion curves of fundamental mode Rayleigh waves. The study region was divided into grids with 0.1°×0.1°; group velocity distributions of Rayleigh waves from 6-22 s were determined with the Occam＇s inversion technique. These velocity distribution maps show the lateral velocity variations in the study area, and the velocity structures are correlated with surface geology and tectonic units. The Yinchuan （银川） basin is clearly featured with low velocities, and the Helan （贺兰） Mountain and southern mountain areas are revealed with high velocities.展开更多
A shear-wave velocity model of the crust and uppermost mantle beneath the SE Tibetan plateau was derived by inverting Rayleigh-wave group-velocity mea- surements of periods between 10 and 70 s. Rayleigh-wave group-vel...A shear-wave velocity model of the crust and uppermost mantle beneath the SE Tibetan plateau was derived by inverting Rayleigh-wave group-velocity mea- surements of periods between 10 and 70 s. Rayleigh-wave group-velocity dispersions along more than 3,000 inter- station paths were measured based on analysis of telese- ismic wavelbrm data recorded by temporary seismic stations. These observations were then utilized to construct 2D group-velocity maps in the period range of 10-70 s. Tile new group-velocity maps have an enhanced resolution compared with previous global and regional group-velocity models in this region because of the denser and more uniform data coverage. The lateral resolution across the region is about 0.5° for the periods used in this study. Local dispersion curves were then inverted for a 3D shear-wave velocity model of the region by applying a linear inversion scheme. Our 3D shear-wave model confirms the presence of low-velocity zones （LVZs） in the crust beneath the northern part of this region. Our irnaging shows that the upper-middle crustal LVZ beneath the Tengchong region is isolated from these LVZs beneath the eastern and northern part of this region. The upper-middle crustal LVZ may be regarded as evidence of a rnagma chamber in the crust beneath the Tengchong Volcanoes. Our model also reveals a slow lithospheric structure beneath Tengchong and a fast shield-like mantle beneath the stable Yangtze block.展开更多
Linear wave theory and Longuet-Higgins and Steward’s (1964) group-induced second-order longweve (GSLW) theory ware used in this study on the grouping effect on wave forces acting on a verticalbreakwater. The calculat...Linear wave theory and Longuet-Higgins and Steward’s (1964) group-induced second-order longweve (GSLW) theory ware used in this study on the grouping effect on wave forces acting on a verticalbreakwater. The calculated variance of total wave pressure on the vertical breakwater was closer tothe measured value if the wave grouping effect was considered.展开更多
Two-month continuous waveforms of 108 broadband seismic stations in Fujian Province and its adjacent areas are used to compute noise cross-correlation function(NCF). The signal quality of NCF is improved via the appli...Two-month continuous waveforms of 108 broadband seismic stations in Fujian Province and its adjacent areas are used to compute noise cross-correlation function(NCF). The signal quality of NCF is improved via the application of time-frequency phase weighted stacking. The Rayleigh and Love waves group velocities between 1 s-20 s are measured on the symmetrical component of the NCF with the multiple filter method. More than 5,000 Rayleigh wave dispersion curves and about 4,000 Love wave dispersion curves are obtained and used to invert for group velocity maps. This data set provides about 50 km resolution that is demonstrated with checkerboard tests. Considering the off great circle effect in inhomogeneous medium, the ray path is traced based on the travel time field computed with a finite difference method. The inverted group velocity maps show good correlation with the geological features in the upper and middle crust. The Fuzhou basin and Zhangzhou basin showed low velocity on the short period group velocity maps. On the long period group velocity maps, the low velocity anomaly in the high heat flow region near Zhangzhou and clear velocity contrast across the Zhenghe-Dapu faults, which suggests that the Zhenghe-Dapu fault might be a deep fault.展开更多
A new method using group-induced second-order long waves (GSLW) to describe wave groups is presented in this paper on the basis of the GSLW theory by Longuet- Higgins and Steward (1964) . In the method , the parabolic...A new method using group-induced second-order long waves (GSLW) to describe wave groups is presented in this paper on the basis of the GSLW theory by Longuet- Higgins and Steward (1964) . In the method , the parabolic relationship between GSLW and the wave envelope is first deduced , and then the distribution function of GSLW amplitude is derived . Thus, the formulae in terms of the moments of GSLW and short wave spectra for the average time duration and the mean length of runs of wave heights exceeding a certain level can be derived . A new groupiness factor equivalent to half the mean wave number in wave groups is defined by taking into account the widths of spectra of GSLW and short waves . Compared with theoretical results of others , ours are closer to measured wave data .展开更多
A method using group-induced second-order long waves(GSLW) to represent statistical properties of wave groups with double-peaked spectra is put forward in this paper on the basis of the GSLW theory. The GSLW is regard...A method using group-induced second-order long waves(GSLW) to represent statistical properties of wave groups with double-peaked spectra is put forward in this paper on the basis of the GSLW theory. The GSLW is regarded as a weighted linear superimposition of the second-order long Wave induced by the low peak frequency section and that induced by the high peak frequency section. There is a parabolic relationship between the GSLW and the wave envelope. Then the probability density function and the distribution function of the GSLW amplitude are derived. Thus the formulas for the average time duration and the mean length of runs can be derived. Good agreement between theoretical results and measured values was achieved. as verified with the measured double-peaked spectra in different regions.展开更多
A carrier wave in a 5-dimensional wave group is examined for information on electromagnetic waves and on particle probability amplitudes. Simulations by Maxwell’s equations show that the phase and group velocities in...A carrier wave in a 5-dimensional wave group is examined for information on electromagnetic waves and on particle probability amplitudes. Simulations by Maxwell’s equations show that the phase and group velocities in electromagnetic waves are equal, both in vacuo and in dielectric media. By contrast, particle probability amplitudes in wave packet motion are more complicated. A dependence of rest mass on relative phase and group velocities is derived by consistency. Occurrences that are simultaneous and connected on wave fronts in the rest frame, appear separated when observed in moving frames. Uncertainties in space and time are linked by the probability amplitude wave group.展开更多
The travelling wave group is a solution to the wave equation. With a Gaussian envelope, this stable wave does not spread as it propagates. The group is derived for electromagnetic waves and converted with Planck’s la...The travelling wave group is a solution to the wave equation. With a Gaussian envelope, this stable wave does not spread as it propagates. The group is derived for electromagnetic waves and converted with Planck’s law to quantized photons. The resulting wave is a probability amplitude, and this is adapted to particles subject to special relativity. By including mass and by inverting the wave group, a description for antiparticles is derived. The consequent explanation is consistent with Dirac’s relativistic equation and with his theory of the electron;while being more specific than his idea of the wave packet, and more stable. The travelling wave group is extended to describe the positron, either free or in an external field.展开更多
The travelling wave group is a stable wave packet. Many surprising results are derived from it. The group is easily quantized for photons and applied, as a solution to the relativistic Klein-Gordon equation, to free p...The travelling wave group is a stable wave packet. Many surprising results are derived from it. The group is easily quantized for photons and applied, as a solution to the relativistic Klein-Gordon equation, to free particles. Further solutions to the resulting algebraic equation provide a stable wave function for free antiparticles. Consistency with the superstructure of quantum electrodynamics is obtained by an assignment to the electron antiparticle of negative mass and negative charge. Then in 5-dimensional space-time-mass, CPT invariance transforms to M’PT conservation in either charged or neutral particles, while many other consequences are also evident.展开更多
Three methods for studying wave groups and their main parameters for describing wave groupiness are reviewed in this paper. Then they are analyzed and compared combined with field data from both aspects of group heigh...Three methods for studying wave groups and their main parameters for describing wave groupiness are reviewed in this paper. Then they are analyzed and compared combined with field data from both aspects of group height and group length. A method and two parameters that can describe wave groupiness are suggested. The groupiness parameters of sea waves at three field stations are given. The effects of groupiness on both distributions of the wave height and the phase of component waves are investigated. The effects of datum length on the calculated value of grouping parameters are also discussed.展开更多
Coupled dynamic analysis of the Deep Draft Multi-Spar （DDMS） platform and the mooring system under the action of waves and current is carried out in the time domain. Using a geometrically nonlinear finite element me...Coupled dynamic analysis of the Deep Draft Multi-Spar （DDMS） platform and the mooring system under the action of waves and current is carried out in the time domain. Using a geometrically nonlinear finite element method, the mooring-line dynamics is simulated based on the total Lagrangian formulation. Wave groups are obtained by the JONSWAP spectrum and an empirical wave envelope spectrum involving two envelope-based factors Group Height Factor （GFH） and Group Length Factor （GLF）. The results show that the wave groups have a significant effect on the motion responses of the platform and the mooring line tensions.展开更多
The evolution of the nonlinear wave groups in deep water is investigated through laboratory measurements and numerical analysis.Laboratory experiments are conducted in deep-water wave tank,focusing on the characterist...The evolution of the nonlinear wave groups in deep water is investigated through laboratory measurements and numerical analysis.Laboratory experiments are conducted in deep-water wave tank,focusing on the characteristics of breaking waves arising from the evolved wave train.Some quantitative results are obtained for the significant breaking wave train,including the surface elevation time series,the local geometry,and the energy dissipation.A nonlinear model for the evolution of the wave groups in deep water is developed by adding eddy viscosity dissipation terms in the High Level Irrotational Green-Naghdi(HLIGN)equations.The results of the simulation are compared with the laboratory measurements,and good agreement is observed for the evolved wave train.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 52371277)the State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation (Tianjin University)(Grant No. HESS-2323)+2 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province (Grant No. KYCX24_4071)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2023A1515010890)the Open foundation of Key Laboratory of Port.Waterway&Sedimentation Engineering (Grant No. Yk224001-1)。
文摘This paper explores the phenomenon of fluid resonance occurring within a narrow gap between a vessel and a vertical wharf, taking ships berthing in front of a gravity wharf as the research background. Using the open-source software Open FOAM~?, a two-dimensional viscous-flow numerical wave flume was developed to simulate the fluid resonant motions induced by transient focused wave groups with different spectral peak periods and wave amplitudes. The results indicate that for all the incident focused wave amplitudes considered, the amplitudes of the free surface elevation in the gap, horizontal wave force and moment all exhibit a bimodal variation trend with increasing spectral peak period. The peak values of the above amplitude-period curve appear near the resonant period of the first and second harmonic components of the free surface elevation. However, the variation in the vertical wave force versus the spectral peak period presents different patterns. In addition, the first-to fourth-order harmonic components in the wave surface and forces are further examined via the four-phase combination method. The results show that the first-to secondorder harmonic components play a dominant role in the overall amplitude.
基金The National High Technology Research and Development Program of China under contract No.2012AA052602the National Natural Science Foundation of China under contract Nos 51079023 and 50921001
文摘The physical simulation method of wave groups in a wave flume is proposed and verified by the exper- iments. The experimental results demonstrate that random waves with desired wave groupiness, which simultaneously includes the wave group height and length, can be generated satisfactorily at the specified position in a wave flume using the proposed method. Furthermore, the transformation properties of the wave groupiness along the fiat-bottomed wave flume are investigated based on the physically simulated waves. Associated proposals with the physical simulation of wave groups are given.
基金Supported by the National Science Foundation of China (No. 40576007)the New Century Excellent Talent Foundation from Education Ministry of China (No. NCET-08-0509)
文摘Wave group is important in ocean wave theory and applications. In the past, nonlinear interaction among wave groups has been studied on the basis of the nonlinear Sehrrdinger equation. Using this theoretical approach, we found that the nonlinear interaction among wave groups causes asymmetry in the shape of the wave envelope （steeper in the front of the curve of the envelope）. An important consequence of this asymmetry is that the highest wave in a wave group appears one individual wave length ahead of the center of the wave group. Further results show that the degree of envelope asymmetry increases with increasing spectral width and the wave steepness. This theoretical analysis has been supplemented by a systematic experimental study of wind waves. Laboratory and some open sea wave data were analyzed. The results show that the shape of the wind wave envelope of wind waves has the same asymmetry predicted by the theoretical approach. The observed degree of deformation of the envelope also increases with increasing spectral width and the wave steepness as predicted by theory. These conclusions have important ramifications for practical applications of ocean wave theory.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51079023 and 50921001)the Program for New Century Excellent Talents in University (Grant No. NCET-05-0282)
文摘Real waves are multidirectional waves. In the present study, the calculation method for the wave maker driving signals for generating multidirectional wave groups in physical wave basin is proposed. Its validity is first confirmed by a numerical model for which the incident boundary condition is determined by use of the proposed method. Then, the physical simulation of multidirectional wave groups is performed in laboratory wave basin. The experimental results show that multidirectional waves with expected wave groupiness, which includes not only its group height but also its group length, can be satisfactorily zenerated at the soecified oosition in the tphvsical wave basin.
基金This work was financially supported by the National Natural Science Foundation of China (Grant No50479028)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No20060423009)
文摘The new distributions of the statistics of wave groups based on the maximum entropy principle are presented. The maximum entropy distributions appear to be superior to conventional distributions when applied to a limited amount of information. Its applications to the wave group properties show the effectiveness of the maximum entropy distribution. FFF filtering method is employed to obtain the wave envelope fast and efficiently. Comparisons of both the maximum entropy distribution and the distribution of Longuet-Higgins （1984） with the laboratory wind-wave data show that the former gives a better fit.
文摘Based on field wave data, an empirical formula of wave envelope spectrum is given in this paper. Then the methods of both numerical and physical simulation of sea wave groups with the given spectrum and groupiness parameters are suggested.
基金supported by the National Natural Science Foundation of China(Grant Nos.40830959 and 41276010)
文摘Knowledge on intermittency of wave breaking is so far limited to a few summary statistics, while the probability distribution of time interval between breaking events can provide a full view of intermittency. Based on a series of experiments on wind wave breaking, such probability distributions are investigated. Breaking waves within a wave group were taken as a single breaking event according to recent studies. Interval between successive wave groups with breaker is the focus of this paper. For intervals in our experiments with different fetch and wind conditions, their distributions are all skewed and weighted on small intervals. Results of Kolmogorov-Smirnov tests on time series of these intervals indicate that they all follow gamma distribution, and some are even exponential type. Average breaking-group-interval decreases with friction velocity and significant steepness until the wind is strong enough;most of them are more than 10 times the dominant wave period. Group breaking probability proposed by Babanin recently and the average number of breaking waves in wave groups are also discussed, and they are seemingly more reasonable and sensitive than traditional breaking probability defined in terms of single wave.
文摘-The effect of wave group on wave run-up on a slope dike is mainly discussed in this paper. Two simulating methods of wave group and their applications in laboratory are introduced. Synthesizing the research results of wave run-up on a slope dike, the effect of wave group on wave run-up on a slope dike in coastal protection engineering is studied as the main point.
基金supported by the Open Fund of Key Laboratory of Geo-detection (China University of Geosciences, Beijing),Ministry of Education of China (No. GDL0708)
文摘In this article, seven months ambient noise data and 10 events recorded at seven digital stations from the Ningxia （宁夏） regional seismic network and 5 500-t controlled source explosion data recorded by 15 temporary and 7 permanent seismic stations are used to measure dispersion curves of fundamental mode Rayleigh waves. The study region was divided into grids with 0.1°×0.1°; group velocity distributions of Rayleigh waves from 6-22 s were determined with the Occam＇s inversion technique. These velocity distribution maps show the lateral velocity variations in the study area, and the velocity structures are correlated with surface geology and tectonic units. The Yinchuan （银川） basin is clearly featured with low velocities, and the Helan （贺兰） Mountain and southern mountain areas are revealed with high velocities.
基金supported by the China National Special Fund for Earthquake Scientific Research in Public Interest(201008001)NSFC(41074067)
文摘A shear-wave velocity model of the crust and uppermost mantle beneath the SE Tibetan plateau was derived by inverting Rayleigh-wave group-velocity mea- surements of periods between 10 and 70 s. Rayleigh-wave group-velocity dispersions along more than 3,000 inter- station paths were measured based on analysis of telese- ismic wavelbrm data recorded by temporary seismic stations. These observations were then utilized to construct 2D group-velocity maps in the period range of 10-70 s. Tile new group-velocity maps have an enhanced resolution compared with previous global and regional group-velocity models in this region because of the denser and more uniform data coverage. The lateral resolution across the region is about 0.5° for the periods used in this study. Local dispersion curves were then inverted for a 3D shear-wave velocity model of the region by applying a linear inversion scheme. Our 3D shear-wave model confirms the presence of low-velocity zones （LVZs） in the crust beneath the northern part of this region. Our irnaging shows that the upper-middle crustal LVZ beneath the Tengchong region is isolated from these LVZs beneath the eastern and northern part of this region. The upper-middle crustal LVZ may be regarded as evidence of a rnagma chamber in the crust beneath the Tengchong Volcanoes. Our model also reveals a slow lithospheric structure beneath Tengchong and a fast shield-like mantle beneath the stable Yangtze block.
文摘Linear wave theory and Longuet-Higgins and Steward’s (1964) group-induced second-order longweve (GSLW) theory ware used in this study on the grouping effect on wave forces acting on a verticalbreakwater. The calculated variance of total wave pressure on the vertical breakwater was closer tothe measured value if the wave grouping effect was considered.
基金sponsored by the Youth Foundation of Fujian Earthquake Agency(Y201710)the Basic Research Fund of the Institute of Earthquake Forecasting,China Earthquake Administration(2015IES010302)
文摘Two-month continuous waveforms of 108 broadband seismic stations in Fujian Province and its adjacent areas are used to compute noise cross-correlation function(NCF). The signal quality of NCF is improved via the application of time-frequency phase weighted stacking. The Rayleigh and Love waves group velocities between 1 s-20 s are measured on the symmetrical component of the NCF with the multiple filter method. More than 5,000 Rayleigh wave dispersion curves and about 4,000 Love wave dispersion curves are obtained and used to invert for group velocity maps. This data set provides about 50 km resolution that is demonstrated with checkerboard tests. Considering the off great circle effect in inhomogeneous medium, the ray path is traced based on the travel time field computed with a finite difference method. The inverted group velocity maps show good correlation with the geological features in the upper and middle crust. The Fuzhou basin and Zhangzhou basin showed low velocity on the short period group velocity maps. On the long period group velocity maps, the low velocity anomaly in the high heat flow region near Zhangzhou and clear velocity contrast across the Zhenghe-Dapu faults, which suggests that the Zhenghe-Dapu fault might be a deep fault.
基金This project was funded by the National Natural Science Foundation of China
文摘A new method using group-induced second-order long waves (GSLW) to describe wave groups is presented in this paper on the basis of the GSLW theory by Longuet- Higgins and Steward (1964) . In the method , the parabolic relationship between GSLW and the wave envelope is first deduced , and then the distribution function of GSLW amplitude is derived . Thus, the formulae in terms of the moments of GSLW and short wave spectra for the average time duration and the mean length of runs of wave heights exceeding a certain level can be derived . A new groupiness factor equivalent to half the mean wave number in wave groups is defined by taking into account the widths of spectra of GSLW and short waves . Compared with theoretical results of others , ours are closer to measured wave data .
基金This project was funded by the National Natural Science Foundation of China
文摘A method using group-induced second-order long waves(GSLW) to represent statistical properties of wave groups with double-peaked spectra is put forward in this paper on the basis of the GSLW theory. The GSLW is regarded as a weighted linear superimposition of the second-order long Wave induced by the low peak frequency section and that induced by the high peak frequency section. There is a parabolic relationship between the GSLW and the wave envelope. Then the probability density function and the distribution function of the GSLW amplitude are derived. Thus the formulas for the average time duration and the mean length of runs can be derived. Good agreement between theoretical results and measured values was achieved. as verified with the measured double-peaked spectra in different regions.
文摘A carrier wave in a 5-dimensional wave group is examined for information on electromagnetic waves and on particle probability amplitudes. Simulations by Maxwell’s equations show that the phase and group velocities in electromagnetic waves are equal, both in vacuo and in dielectric media. By contrast, particle probability amplitudes in wave packet motion are more complicated. A dependence of rest mass on relative phase and group velocities is derived by consistency. Occurrences that are simultaneous and connected on wave fronts in the rest frame, appear separated when observed in moving frames. Uncertainties in space and time are linked by the probability amplitude wave group.
文摘The travelling wave group is a solution to the wave equation. With a Gaussian envelope, this stable wave does not spread as it propagates. The group is derived for electromagnetic waves and converted with Planck’s law to quantized photons. The resulting wave is a probability amplitude, and this is adapted to particles subject to special relativity. By including mass and by inverting the wave group, a description for antiparticles is derived. The consequent explanation is consistent with Dirac’s relativistic equation and with his theory of the electron;while being more specific than his idea of the wave packet, and more stable. The travelling wave group is extended to describe the positron, either free or in an external field.
文摘The travelling wave group is a stable wave packet. Many surprising results are derived from it. The group is easily quantized for photons and applied, as a solution to the relativistic Klein-Gordon equation, to free particles. Further solutions to the resulting algebraic equation provide a stable wave function for free antiparticles. Consistency with the superstructure of quantum electrodynamics is obtained by an assignment to the electron antiparticle of negative mass and negative charge. Then in 5-dimensional space-time-mass, CPT invariance transforms to M’PT conservation in either charged or neutral particles, while many other consequences are also evident.
文摘Three methods for studying wave groups and their main parameters for describing wave groupiness are reviewed in this paper. Then they are analyzed and compared combined with field data from both aspects of group height and group length. A method and two parameters that can describe wave groupiness are suggested. The groupiness parameters of sea waves at three field stations are given. The effects of groupiness on both distributions of the wave height and the phase of component waves are investigated. The effects of datum length on the calculated value of grouping parameters are also discussed.
基金supported by the National Natural Science Foundation of China (Grant No. 50921001)the National High Technology Research and Development Program of China (863 Program, Grant No. 2007AA11Z130)
文摘Coupled dynamic analysis of the Deep Draft Multi-Spar （DDMS） platform and the mooring system under the action of waves and current is carried out in the time domain. Using a geometrically nonlinear finite element method, the mooring-line dynamics is simulated based on the total Lagrangian formulation. Wave groups are obtained by the JONSWAP spectrum and an empirical wave envelope spectrum involving two envelope-based factors Group Height Factor （GFH） and Group Length Factor （GLF）. The results show that the wave groups have a significant effect on the motion responses of the platform and the mooring line tensions.
基金Projects supported by the National Natural Science Foundation of China(Grant No.11772099)the Heilongjiang Touyan Innovation Team Program,China.
文摘The evolution of the nonlinear wave groups in deep water is investigated through laboratory measurements and numerical analysis.Laboratory experiments are conducted in deep-water wave tank,focusing on the characteristics of breaking waves arising from the evolved wave train.Some quantitative results are obtained for the significant breaking wave train,including the surface elevation time series,the local geometry,and the energy dissipation.A nonlinear model for the evolution of the wave groups in deep water is developed by adding eddy viscosity dissipation terms in the High Level Irrotational Green-Naghdi(HLIGN)equations.The results of the simulation are compared with the laboratory measurements,and good agreement is observed for the evolved wave train.
