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1.
Using Boussinesq scaling for water waves while imposing no constraints on rotationality, we derive and test model equations for nonlinear water wave transformation over varying depth. These use polynomial basis functions to create velocity profiles which are inserted into the basic equations of motion keeping terms up to the desired Boussinesq scaling order, and solved in a weighted residual sense. The models show rapid convergence to exact solutions for linear dispersion, shoaling, and orbital velocities; however, properties may be substantially improved for a given order of approximation using asymptotic rearrangements. This improvement is accomplished using the large numbers of degrees of freedom inherent in the definitions of the polynomial basis functions either to match additional terms in a Taylor series, or to minimize errors over a range. Explicit coefficients are given at O(μ2) and O(μ4), while more generalized basis functions are given at higher order. Nonlinear performance is somewhat more limited as, for reasons of complexity, we only provide explicitly lower order nonlinear terms. Still, second order harmonics may remain good to kh ≈ 10 for O(μ4) equations. Numerical tests for wave transformation over a shoal show good agreement with experiments. Future work will harness the full rotational performance of these systems by incorporating turbulent and viscous stresses into the equations, making them into surf zone models. 相似文献
2.
《Marine Policy》2002,26(5):337-343
This paper chronicles and analyzes the political dispute that resulted when Russia gave South Korea permission to fish for saury in the Kurile area disputed by Russia and Japan. The dispute became a three-sided diplomatic wrangle and threatened to disrupt relations between the countries involved. In the resolution of the dispute, each side gained and lost both politically and economically. Given the difficult political relations in Northeast Asia, fisheries policy makers should consider the international political ramifications of their decisions. 相似文献
3.
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
4.
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
5.
《Marine and Petroleum Geology》2013,39(1):53-72
Evaluation of the reservoir quality of the Triassic Halfway–Montney–Doig hybrid gas shale/tight gas reservoir in the Groundbirch field in northeastern British Colombia requires an integration of unconventional and conventional methodologies. Reservoir evaluation includes reservoir thickness and structure, total porosity, TOC content, organic maturity, pore size distribution (micro- to macro-pore size fractions), surface area, mineralogy and pulse-decay permeability. Quartz (10–74%), carbonate (13–73%) and feldspar (0–42%) dominate the mineralogy of all formations with illite (0–32%) being locally important. The Tmax values range between 443 and 478 °C placing the reservoirs beyond the oil window. Pore size distribution by low-pressure gas adsorption analysis identifies a large variation between the contributions from the micro-, meso- and macro-pore size fractions. Matrix permeabilities range between 1.0E-3 and 6.5E-7 mD at an effective stress between 2400 and 3300 PSI (16.5–22.8 MPa).Changes in depositional environments and diagenetic processes manifest as differences in lithology and mineralogy within the Montney and Doig reservoirs which subsequently affect the fabric, texture and pore size distribution. Fabric, texture and pore size distribution contribute to the variation in the permeability and the proportions of free to sorbed gas within the reservoir. Quartz-rich, coarser-grained intervals (upper portions of Doig C, B and Halfway Formation) have lower surface area, greater porosities and a higher volume of macropores compared to the carbonate- and clay-rich finer-grained intervals (Doig A). Permeabilities do not vary according to lithology with higher permeabilities found within both fine-grained (Doig A) and coarser-grained (Halfway Formation) units. Permeability is controlled by pore size distribution. Higher permeability samples contain a balanced ratio between micro-, meso- and macro-porosity. The finer-grained intervals have higher sorbed gas capacity due to higher surface areas because of the higher volumes of finer mesopores and micropores than the coarser-grained units. However, porosity and permeability are low in some parts of the Doig A and fracture stimulation is necessary to achieve economic flow rates. 相似文献
6.
《Deep Sea Research Part I: Oceanographic Research Papers》1999,46(10):1671-1703
Within the framework of the Tunisian – EC SALTO/AVICENNE project, four hydrological sections were performed between Tunisia, Sardinia and Sicily with a 10–20 km sampling interval in April–June 1995. To our knowledge, it is the first time that sections were repeated there at such a high frequency. These data significantly increase the number of observations available on the Tunisian side of the Channels of Sardinia and Sicily, and allow reliable specification of the hydrological characteristics of the area. For the first time, and as confirmed by infrared satellite images, these data sets show (i) the large mesoscale variability of the surface flow entering the study area, as expected from the characteristics of the Algerian Current upstream, (ii) the rapid changes it undergoes around northeastern Tunisia, as it shifts roughly from southward to eastward within less than a few weeks. These data also show a large heterogeneity at intermediate levels, clearly associated with waters of very different origins that follow converging routes and mix in both the study area and the southern Tyrrhenian Sea. They finally document the fundamental importance of bathymetric features of relatively small scale such as the Skerki passage. 相似文献
7.
基于一套涡分辨模式数据,本文利用一种新的泛函工具—多尺度子空间变换—将孟加拉湾（BOB）海域的环流系统分解到背景流（>96 d）、中尺度（24～96 d）和高频尺度（<24 d）3个子空间,并用正则传输理论探讨了3个尺度子空间之间内在的非线性相互作用。结果表明,BOB西北部边界和斯里兰卡岛东部是BOB海域多尺度相互作用最显著的区域,中部则较弱。前两个区域的背景流大多正压、斜压不稳定,动能和有效位能正则传输主要表现为正向级串;后者则以逆尺度动能级串为主。具体来说,在BOB西北部与斯里兰卡东部,中尺度涡动能（EKE）主要来源于正压能量路径（即背景流动能向EKE传输）,其次来源于斜压能量路径（即背景流有效位能向中尺度有效位能传输,并进一步转换为EKE）。通过这两个能量路径得到的EKE向更高频的扰动传输能量,起到了耗散中尺度涡的作用。不同于此二者,BOB中部海域的EKE和高频尺度动能主要通过斜压路径获得,随后通过逆尺度级串将动能返还给背景流。苏门答腊岛的西北部也是中尺度和高频尺度扰动较强的海域,正压能量路径和斜压能量路径均是该海域扰动能的来源,但以斜压能量路径为主。 相似文献
8.
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
9.
G. W. Yeates 《新西兰海洋与淡水研究杂志》2013,47(3):472-496
The adult population of the colony, egg sizes, incubation watches, and egg and chick mortality are considered for the 1964–65 and 1965–66 breeding seasons. In 1964–65 1,051 breeding pairs were recorded and 1,467 chicks survived to leave the colony: this represents 67.5% of eggs laid. In 1965–66 1,186 breeding pairs successfully reared 1,390 chicks: 57.0% of eggs laid. Egg and chick mortality over four breeding seasons is considered, with special reference to ice conditions in McMurdo Sound. Dimensions of 349 eggs are given, including those for clutches produced by 33 known females in successive seasons. Breeding success of known pairs of birds is discussed. Birds breeding for the first time appear to lay a single, small egg and to be unsuccessful; experienced breeders which change their mate are usually unsuccessful. Observations are made on chick plumage and panting. A prone sleeping posture in which the bill is directed towards the axilla is described and illustrated. Some observations on the South Polar Skua are recorded. 相似文献
10.
《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
11.
Sea-crossing bridges are affected by random wind–wave–undercurrent coupling loads, due to the complex marine environment. The dynamic response of long-span Rail-cum-Road cable-stayed bridges is particularly severe under their influence, potentially leading to safety problems. In this paper, a fluid–structure separation solution method is implemented using Ansys–Midas co-simulation, in order to solve the above issues effectively while using less computational resources. The feasibility of the met... 相似文献
12.
Understanding the drifting motion of a small semi-submersible drifter is of vital importance regarding monitoring surface currents and the floating pollutants in coastal regions. This work addresses this issue by establishing a mechanistic drifting forecast model based on kinetic analysis. Taking tide–wind–wave into consideration, the forecast model is validated against in situ drifting experiment in the Radial Sand Ridges. Model results show good performance with respect to the measured drifting features, characterized by migrating back and forth twice a day with daily downwind displacements. Trajectory models are used to evaluate the influence of the individual hydrodynamic forcing. The tidal current is the fundamental dynamic condition in the Radial Sand Ridges and has the greatest impact on the drifting distance. However, it loses its leading position in the field of the daily displacement of the used drifter. The simulations reveal that different hydrodynamic forces dominate the daily displacement of the used drifter at different wind scales. The wave-induced mass transport has the greatest influence on the daily displacement at Beaufort wind scale 5–6; while wind drag contributes mostly at wind scale 2–4. 相似文献
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Coupled SPHS–BEM method is proposed for transient fluid–structure interaction problems: SPH shell (SPHS) is selected to discretize shell structures, the second-order doubly asymptotic approximations (DAA2) of boundary element method (BEM) is chosen to analyze flow-field. BEM can remedy the expensive costs for three-dimensional SPH (smoothed particle hydrodynamics), yet SPHS provides a structural solver for BEM. The coupled method is attractive, since only a layer of SPHS particles and a piece of flow-field boundary elements are needed to be modeled; the compatibility conditions of the coupled surface are performed with moving least square (MLS) function. The final two benchmarks on underwater impacts prove the feasibility, stability and accuracy of the proposed method. 相似文献
16.
I. I. Mokhov 《Izvestiya Atmospheric and Oceanic Physics》2017,53(5):550-563
The results of Russian climate studies (published in 2011–2014) based on the review prepared for the National Report on Meteorology and Atmospheric Sciences submitted to the 26th General Assembly of the International Union of Geodesy and Geophysics (Prague, June 22–July 2, 2015)1 are presented. 相似文献
17.
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
18.
《Marine Policy》2015
This article discusses the role of negotiation, arbitration, and that of the International Court of Justice (ICJ) in resolving maritime boundary disputes in the Gulf of Guinea region. Primarily using the cases of Guinea-Bissau and Senegal, the paper highlights that joint maritime development agreements could be a better option for resolving existing maritime boundary disputes in the region rather than outright delimitation requests. 相似文献
19.
Green–Naghdi (GN) theory is a fully nonlinear wave theory which has been used with success to simulate nonlinear water waves. In previous applications of GN theory to water wave problems the ocean bottom was assumed to be time invariant. In this work no such restriction is made and GN theory is used to simulate tsunami caused by bottom fluctuation. As first test cases we simulate two-dimensional nonlinear surface waves generated by positive bottom movements. The results in the generation region for three different seabed movements compare well against earlier experimental data. The results in the downstream region for impulsive seabed movements show some discrepancies in wave phase and amplitude compared with earlier experimental values. It is suspected that the viscous effects may have played a role. The GN theory is then used to study three-dimensional near-field tsunami amplitudes caused by submarine landslides and slumps spreading in two orthogonal directions. The GN results agree with previous linear solution very well when the ratio of the velocities is v1/v2=1.0. But GN theory give more believable results for the case of vT/v=0.1 and v1/v2=0.1. 相似文献
20.
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