To investigate the nonlinear properties of wind waves, experiments are carried out in a wind-wave flume with slope bottom at different wind speeds and fetches. Both the internal structure and apparent features of the ...To investigate the nonlinear properties of wind waves, experiments are carried out in a wind-wave flume with slope bottom at different wind speeds and fetches. Both the internal structure and apparent features of the nonlin-earity of wind waves are studied by using bispectral and statistical analysis of surface elevations. The relations between bispectra and nonlinear apparent characteristics of wind waves are established and confirmed.展开更多
In this work,an enriched model describing the longitudinal wave propagation is established based on Mindlin’s Second Strain Gradient(SSG)theory,which can describe the heterogeneity caused by the micro-structure inter...In this work,an enriched model describing the longitudinal wave propagation is established based on Mindlin’s Second Strain Gradient(SSG)theory,which can describe the heterogeneity caused by the micro-structure interactions in the frame of continuum mechanics.The governing equation and associated boundary conditions are derived based on Hamilton’s principle,then the dispersion relation of non-classical longitudinal wave together with the extra-waves appearing exclusively in SSG theory model are investigated.The investigations are based on the modal density,energy flow,and forced response of the rod.Wave transmission and reflection through planar interfaces based on the proposed model have been calculated.Finally,the results of the enriched model are well interpreted by comparing with the classical theory results,and some useful conclusions are derived on the SSG theory based model in the wave propagation characterization.展开更多
The Deep Seismic Sounding( DSS) projects carried out from the 1970 s in the lower Yangtze region and its neighboring area were reviewed in this paper,then the basic wave group features of those wide angle reflection /...The Deep Seismic Sounding( DSS) projects carried out from the 1970 s in the lower Yangtze region and its neighboring area were reviewed in this paper,then the basic wave group features of those wide angle reflection / refraction record sections,and of the crustal structure are summarized. It shows that there were in total five clear wave groups on the record sections,which include the first arrival Pg,the reflection P1 from the bottom interface of the upper crust,the reflection P3 from the bottom interface of the middle crust,the strong reflection Pm from the Moho boundary,and the refraction Pn from uppermost mantle. In general,these phases are easily consistently traced and compared,despite some first arrivals being delayed or arriving earlier than normal due to the shallow sedimentary cover or bedrocks. In particular,in the Dabie Mountain region the seismic events of a few gathered shots always have weak reflection energy,are twisted,or exhibit disorganized waveforms, which could be attributed to the disruption variations of reflection depth,the broken Moho,and the discontinuity of the reflection boundary within crust. The regional crustal structures are composed of the upper,middle and lower crust,of which the middle and lower layers can be divided into two weak reflection ones. The crustal thickness of the North China and Yangtze platform are 30km- 36 km,and the Moho exhibits a flat geometry despite some local uplifts. The average pressure velocity in lower crust beneath this two tectonic area is 6. 7 ± 0. 3km / s. Nevertheless,beneath the Dabieshan area the crustal thickness is 32km- 41 km,the Moho bends down sharply andtakes an abrupt 4km- 7km dislocation in the vertical direction. The average pressure velocity in the lower crust beneath the Dabieshan area is 6. 8 ± 0. 2km / s.展开更多
The significant wave height prediction holds critical value for marine energy development,coastal infrastructure planning,and ensuring safety in maritime operations.The precision of such predictions carries substantia...The significant wave height prediction holds critical value for marine energy development,coastal infrastructure planning,and ensuring safety in maritime operations.The precision of such predictions carries substantial the oretical and practical weight.This survey delivers an exhaustive evaluation and integration of the latest studies and advances in the domain of significant wave height prediction,serving as a methodical guidepost for academicians.The study introduces an all-encompassing predictive framework for significan wave height,which not only integrates diverse established forecasting techniques but also paves the way for novel research trajectories and creative breakthroughs.The framework is structured into four principal layers i...feature selection,basic prediction,data decomposition,and parameter optimization.The ensuing sections meticulously dissect the methodologies within these strata,elucidating their core concepts,distinctive features merits,and constraints,and their applicability to significant wave height prediction.To wrap up,the study delves into fresh research inguiries and avenues pertinent to the discipline,thereby broadening the comprehension of significant wave height prediction.In essence,this scholarly article imparts critical knowledge beneficial to the realm of marine technology.展开更多
基金This study was supported in part by the National Natural Science Fundation of China
文摘To investigate the nonlinear properties of wind waves, experiments are carried out in a wind-wave flume with slope bottom at different wind speeds and fetches. Both the internal structure and apparent features of the nonlin-earity of wind waves are studied by using bispectral and statistical analysis of surface elevations. The relations between bispectra and nonlinear apparent characteristics of wind waves are established and confirmed.
基金supported by the LabEx CeLyA (Centre Lyonnais d’Acoustique, ANR-10-LABX-0060) of Universitéde Lyon。
文摘In this work,an enriched model describing the longitudinal wave propagation is established based on Mindlin’s Second Strain Gradient(SSG)theory,which can describe the heterogeneity caused by the micro-structure interactions in the frame of continuum mechanics.The governing equation and associated boundary conditions are derived based on Hamilton’s principle,then the dispersion relation of non-classical longitudinal wave together with the extra-waves appearing exclusively in SSG theory model are investigated.The investigations are based on the modal density,energy flow,and forced response of the rod.Wave transmission and reflection through planar interfaces based on the proposed model have been calculated.Finally,the results of the enriched model are well interpreted by comparing with the classical theory results,and some useful conclusions are derived on the SSG theory based model in the wave propagation characterization.
基金funded by the Special Public Welfare Industry Research of China Earthquake Administration(201408023)Academician Chen Yong Workstation Special Funds of Yunnan Province and Natural Science Foundation of China(41374062,41174075)
文摘The Deep Seismic Sounding( DSS) projects carried out from the 1970 s in the lower Yangtze region and its neighboring area were reviewed in this paper,then the basic wave group features of those wide angle reflection / refraction record sections,and of the crustal structure are summarized. It shows that there were in total five clear wave groups on the record sections,which include the first arrival Pg,the reflection P1 from the bottom interface of the upper crust,the reflection P3 from the bottom interface of the middle crust,the strong reflection Pm from the Moho boundary,and the refraction Pn from uppermost mantle. In general,these phases are easily consistently traced and compared,despite some first arrivals being delayed or arriving earlier than normal due to the shallow sedimentary cover or bedrocks. In particular,in the Dabie Mountain region the seismic events of a few gathered shots always have weak reflection energy,are twisted,or exhibit disorganized waveforms, which could be attributed to the disruption variations of reflection depth,the broken Moho,and the discontinuity of the reflection boundary within crust. The regional crustal structures are composed of the upper,middle and lower crust,of which the middle and lower layers can be divided into two weak reflection ones. The crustal thickness of the North China and Yangtze platform are 30km- 36 km,and the Moho exhibits a flat geometry despite some local uplifts. The average pressure velocity in lower crust beneath this two tectonic area is 6. 7 ± 0. 3km / s. Nevertheless,beneath the Dabieshan area the crustal thickness is 32km- 41 km,the Moho bends down sharply andtakes an abrupt 4km- 7km dislocation in the vertical direction. The average pressure velocity in the lower crust beneath the Dabieshan area is 6. 8 ± 0. 2km / s.
基金supported by the Open Project of Xiangjiang Laboratory(No.22XJ02003)National Science Fund for Outstanding Young Scholars(No.62122093)+1 种基金Science&Technology Project for Young and Middle-aged Talents of Hunan(No.2023TJ-Z03)University Fundamental Research Fund(Nos.23-ZZCX-JDZ-28 and ZK21-07).
文摘The significant wave height prediction holds critical value for marine energy development,coastal infrastructure planning,and ensuring safety in maritime operations.The precision of such predictions carries substantial the oretical and practical weight.This survey delivers an exhaustive evaluation and integration of the latest studies and advances in the domain of significant wave height prediction,serving as a methodical guidepost for academicians.The study introduces an all-encompassing predictive framework for significan wave height,which not only integrates diverse established forecasting techniques but also paves the way for novel research trajectories and creative breakthroughs.The framework is structured into four principal layers i...feature selection,basic prediction,data decomposition,and parameter optimization.The ensuing sections meticulously dissect the methodologies within these strata,elucidating their core concepts,distinctive features merits,and constraints,and their applicability to significant wave height prediction.To wrap up,the study delves into fresh research inguiries and avenues pertinent to the discipline,thereby broadening the comprehension of significant wave height prediction.In essence,this scholarly article imparts critical knowledge beneficial to the realm of marine technology.
