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1.
It is known from data analysis that periodic fluctuations are obviously present in theprocess curve representing a storm surge in either the Huanghai Sea or the East China Sea,which has been obtained on the basis of the difference-estimating method. Apart from long-wave effects by storm disturbance, there is a nonlinear interaction between storm surge and 相似文献
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Much attention should be paid to a large FPSO moored permanently in an oil field with water depth of only about 20 m, since shallow water effects on the hydrodynamics may bring about collision and damage. A 160kDWT FPSO with a permanent soft yoke mooring system is investigated with various shallow water depths and focuses are the low frequency surge motion and mooring load. Computation for the FPSO system is made based on linear 3-D potential fluid theory and time-domain numerical simulation method. Corresponding model test is carried out in the ocean engineering basin of Shanghai Jiao Tong University. It is shown that, in the surge natural period, low frequency surge motion and mooring force increase remarkably with the decrease of water depth. Especially, the smaller the ratio of water depth and draught is, the quicker the increase is. The shallow water effects should be taken into account carefully for determining the design load of a single point mooring system. 相似文献
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Review of JONSWAP Spectrum Based on Storm 149 from North Alwyn 总被引：1，自引：0，他引：1
1 .IntroductionItiswellknownthatthewavespectrumisveryusefulforthepredictionofwavecharacteristicsbothinthecomputationofshipmotionandwaveloadonoffshorestructuresandinthesimulationatshipandoceanbasinsformodeltests.InengineeringpracticemanyspectralformulaecanbeselectedforacertainseaareasuchasrecommendedbytheInternationalTowingTankConferenceITTC (TheSpecialistCommitteeofWaves) .TheJONSWAPspectralformulaiswidelyemployedinoceanengi neeringdesignandareviewofitisnecessarybasedonsomemeasureddata… 相似文献
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With the increasing construction of artificial beach in coastal areas, it is of practical significance to study the beach surface deformation of artificial beach profile. Previous studies only focus on a single wave dynamic factor, and it is difficult to predict the beach deformation of artificial beach profile under the storm surge-wave co-action. To solve this problem, the cross-section physical model test method was used to study the beach surface deformation of a typical artificial beach pro... 相似文献
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This paper deals with the hydrodynamic analysis of an array of Oscillating Water Column (OWC) devices, made up of coaxial cylinders, which are floating either independently or as a unit forming a floating platform. The platform is considered either free – floating or as TLP configuration connected to the sea bottom. Numerical results concerning the three boundary value problems, namely, the diffraction, the motion – and the pressure – dependent radiation ones are given. They have been obtained through an analytical solution method using matched axisymmetric eigenfunction expansion formulations. In all cases the interaction phenomena with neighbouring bodies have been taken properly into account using the physical idea of multiple scattering. Numerical results for the first – and the mean second – order wave forces, the hydrodynamic interaction coefficients along with pressure hydrodynamic parameters, inner air pressure and free–surface oscillation amplitude inside and outside of each device are parametrically evaluated and supplemented by experimental data. 相似文献
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On average, five to six storms occur in the Qiongzhou Strait every year, causing significant damage to coastal geomorphology and several property losses. Tropical Storm Bebinca is the most unusual and complex storm event that has occurred in this region over the last 10 years. To detect the high-frequency beachface responses to the storm, a pressure sensor was deployed in the surf zone to record the free sea surface height, and the heights of grid pile points on the beachface were measured manua... 相似文献
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The continuous research and improvement of ocean modelling helps to provide a more sustainable development of coastal and offshore regions. This paper focuses on ocean modelling at the NW Mediterranean using the POLCOMS–WAM model with new developments. The Stokes’ drift effect on currents has been included and the distribution of surface stress between waves and currents has also been considered. The system is evaluated in the NW Mediterranean and an evaluation of different forcing terms is performed. The temperature and salinity distributions control the main patterns of the Mediterranean circulation. Currents are typically small and therefore the modification of waves due to the effect of currents is minimal. However, the wave induced currents, mainly caused by a modified wind drag due to waves, produce changes that become an important source of mass transport. POLCOMS was able to reproduce the main Mediterranean features, its coupling with WAM can be a very useful tool for ocean and wave modelling in the Mediterranean and other shelf seas. 相似文献
9.
Hamid Gadouri Khelifa Harichane Mohamed Ghrici 《Marine Georesources & Geotechnology》2013,31(9):1130-1148
AbstractAn experimental investigation was undertaken in order to assess the effect of sodium (Na2SO4) and calcium (CaSO4·2H2O) sulphates and curing period on stress–strain curves and failure modes of grey (GS) and red (RS) clayey soils stabilised by lime (L), natural pozzolana (NP) and their combinations (L–NP). Several soil–L–NP mixtures were studied to be used as subgrade soils for road pavements. Stress–strain curves were obtained from unconfined compressive strength (UCS) test made on several soil–L–NP specimens after curing for 7 and 120 days. Tests results showed that the use of L or L–NP without sulphates produced a significant increase in peaks stress of both clayey soils and then modified their stress–strain curves from nonlinear to linear behaviour almost up to 70% of peak stress after a longer curing period. However, the presence of 2% Na2SO4 or any CaSO4·2H2O content provided beneficial effects on peaks stress and stress–strain curves of both stabilised clayey soils and then improved their linearity almost up to 95% of peak stress after curing for 120 days. In contrast, the presence of 6% Na2SO4 caused undesirable effects. In addition, both sulphates greatly affected the failure modes of soil–L–NP specimens, particularly at a later stage. 相似文献
10.
Here in present work, rotational Boussinesq–Green–Naghdi models were applied to assess the hydrodynamic intensity through the study of the boulder transport in east coast of Philippines during typhoon Haiyan and damage to coastal residences in New Jersey coast due to hurricane Sandy. The hydrodynamic forces were quantitatively analyzed and correlated to both boulder transport distance and the structural damage state in the two cases. The boulder transport was found initiated at vicinity of infragravity swash bores. Inertial force generated by the acceleration in front of the bore was found increasingly large as boulder sizes increased therefore far from negligible as in some other literatures. Besides, transport distances were highly sensitive to wave-heights and boulder sizes, so that onshore positions might be a viable approach of identifying rough magnitudes of paleostorm before other information is available. Fragility functions to predict the damage state of coastal residences due to runups was derived and preliminary validated. Water velocity and the shielding parameter were identified as major predictors of damage while free board and water depth are relatively insignificant. Due to the relative lack of wind damage observed, nearshore hydrodynamics featuring instantaneous nonhydrostatic impact might be the persistent cause of massive littoral processes and low-level structural failure in coastal regions during extreme marine events. Nonhydrostatic phase-resolving models such as Boussinesq-type models would be necessary complements for the intermediate-scale assessment of marine hazards in coastal ocean. 相似文献
11.
Izvestiya, Atmospheric and Oceanic Physics - This is a review of the results from Russian polar research in 2015–2018 prepared by the Commission on Polar Meteorology of the National... 相似文献
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Oceanology - The specific morphology of the inner and outer slopes of the eastern Kuril–Kamchatka Trench were revealed based on joint study of bathymetry and seismic profiles obtained in two... 相似文献
13.
We have performed a simulation of the convectively induced ascent of the gas–dust cloud formed during the atmospheric passage and explosion of the Chelyabinsk meteoroid. The acceleration, velocity, and rise of the gas–dust cloud have been described as functions of time and altitude. The time of dust settling in the atmosphere has been estimated. The results of calculations are in a close agreement with the observational data. 相似文献
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Permeability–porosity relationships for sediments from the northern Barbados, Costa Rica, Nankai, and Peru subduction zones were examined based on sediment type, grain size distribution, and general mechanical and chemical compaction history. Greater correlation was observed between permeability and porosity in siliciclastic sediments, diatom oozes, and nannofossil chalks than in nannofossil oozes. For siliciclastic sediments, grouping of sediments by percentage of clay-sized material yields relationships that are generally consistent with results from other marine settings and suggests decreasing permeability as percentage of clay-sized material increases. Correction of measured porosities for smectite content improved the correlation of permeability–porosity relationships for siliciclastic sediments and diatom oozes. The relationship between permeability and porosity for diatom oozes is very similar to the relationship in siliciclastic sediments, and permeabilities of both sediment types are related to the amount of clay-size particles. In contrast, nannofossil oozes have higher permeability values by 1.5 orders of magnitude than siliciclastic sediments of the same porosity and show poor correlation between permeability and porosity. More indurated calcareous sediments, nannofossil chalks, overlap siliciclastic permeabilities at the lower end of their measured permeability range, suggesting similar consolidation patterns at depth. Thus, the lack of correlation between permeability and porosity for nannofossil oozes is likely related to variations in mechanical and chemical compaction at shallow depths. This study provides the foundation for a much-needed global database with fundamental properties that relate to permeability in marine settings. Further progress in delineating controls on permeability requires additional carefully documented permeability measurements on well-characterized samples. 相似文献
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《Marine and Petroleum Geology》2003,20(3-4):385-397
Various settings took place during the Late Mesozoic: divergent, convergent, collisional, and transform. After mid-Jurassic collision of the Siberian and Chinese cratons, a latitudinal system of post-collision troughs developed along the Mongol-Okhotsk suture (the Uda, Torom basins and others), filled with terrigenous coal-bearing molasse.The dispersion of Pangea, creation of oceans during the Late Jurassic are correlated to the emergence of the East Asian submeridional rift system with volcano-terrigenous coal-bearing deposits (the Amur-Zeya basin). At that time, to the east there existed an Andean-type continental margin. Foreland (Upper Bureya, Partizansk, and Razdolny) and flexural (Sangjiang-Middle Amur) basins were formed along the margin of the rigid massifs during the Late Jurassic to Berriasian.During the Valanginian-mid-Albian an oblique subduction of the Izanagi plate beneath the Asian continent occurred, producing a transform margin type, considerable sinistral strike slip displacements, and formation of pull-apart basins filled with turbidites (the Sangjiang-Middle Amur basin).The Aptian is characterized by plate reorganization and formation of epioceanic island arcs, fore-arc and back-arc basins in Sakhalin and the Sikhote-Alin (the Alchan and Sangjiang-Middle Amur basins), filled with volcanoclastics.During the mid-Albian a series of terranes accreted to the Asian continental margin. By the end of the Albian, the East Asian marginal volcanic belt began to form due to the subduction of the Kula plate beneath the Asian continent. During the Cenomanian–Coniacian shallow marine coarse clastics accumulated in the fore-arc basins, which were followed by continental deposits in the Santonian–Campanian. From the Coniacian to the Maastrichtian, a thermal subsidence started in rift basins, and continental oil-bearing clastics accumulated (the Amur-Zeya basin).Widespread elevation and denudation were dominant during the Maastrichtian. This is evidenced by thick sediments accumulated in the Western Sakhalin fore-arc basin.During the Cenozoic, an extensive rift belt rmade up of a system of grabens, which were filled with lacustrine–alluvial coal–and oil-bearing deposits, developed along the East Asian margin. 相似文献
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This paper presents a review of the results from Russian studies of the middle atmosphere in 2007–2010 drawn up by the Commission
on the Middle Atmosphere of the Section of Meteorology and Atmospheric Sciences of the National Geophysical Committee, Russian
Academy of Sciences, for the National Report on Meteorology and Atmospheric Sciences submitted to the XXIV General Assembly
of the International Union of Geodesy and Geophysics (Melbourne, Australia, June 28–July 7, 2011). 相似文献
18.
Stereo video techniques are effective for estimating the space–time wave dynamics over an area of the ocean. Indeed, a stereo camera view allows retrieval of both spatial and temporal data whose statistical content is richer than that of time series data retrieved from point wave probes. We present an application of the Wave Acquisition Stereo System (WASS) for the analysis of offshore video measurements of gravity waves in the Northern Adriatic Sea and near the southern seashore of the Crimean peninsula, in the Black Sea. We use classical epipolar techniques to reconstruct the sea surface from the stereo pairs sequentially in time, viz. a sequence of spatial snapshots. We also present a variational approach that exploits the entire data image set providing a global space–time imaging of the sea surface, viz. simultaneous reconstruction of several spatial snapshots of the surface in order to guarantee continuity of the sea surface both in space and time. Analysis of the WASS measurements show that the sea surface can be accurately estimated in space and time together, yielding associated directional spectra and wave statistics at a point in time that agrees well with probabilistic models. In particular, WASS stereo imaging is able to capture typical features of the wave surface, especially the crest-to-trough asymmetry due to second order nonlinearities, and the observed shape of large waves are fairly described by theoretical models based on the theory of quasi-determinism (Boccotti, 2000). Further, we investigate space–time extremes of the observed stationary sea states, viz. the largest surface wave heights expected over a given area during the sea state duration. The WASS analysis provides the first experimental proof that a space–time extreme is generally larger than that observed in time via point measurements, in agreement with the predictions based on stochastic theories for global maxima of Gaussian fields. 相似文献
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Izvestiya, Atmospheric and Oceanic Physics - For regional earthquakes, the kinematic parameter VP/VS, an analog of the TAU parameter, was analyzed in order to study the state of magmatic matter,... 相似文献
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Izvestiya, Atmospheric and Oceanic Physics - New ways to improve the original technique for assessing the albedo of snow–ice surfaces with the use of ground measurements of incoming solar... 相似文献