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1.
Observation of fluid parcel pathways in the Kuroshio Stream revealed a striking crossstream pattern associated with the Kuroshio‘‘ s meanders. In order to understand the observed pattern, a two-dimensional kinematic model of a meandering jet was developed which could be used to examine the relationship between streamfunction patterns and fluid parcel trajectories. The experiments designed to investigate the dependence of the water exchanges between the Kuroshio water and its surroundings on the characteristics of the Kuroshio‘‘s meanders involved the downstream speed,phase speed and the amplitude of other propagating waves. The results suggested that fluid parcels could cross the meandering jet to and fro; and that the water exchanges between the Kuroshio and its surroundings increased with a) increasing meander amplitude, b) decreasing downstream speed, and c) increasing wave phase speed. The results also showed that when the meandering jet was disturbed by other propagating waves, more effective water exchanges could be induced. 相似文献
2.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｏｔｅｓｔｔｈｅｌａｙｅｒｅｄｔｈｒｅｅ ｄｉｍｅｎｓｉｏｎａｌｎｏｎｌｉｎｅａｒｎｕｍｅｒｉｃａｌｍｏｄｅｌｐｒｅｓｅｎｔｅｄｉｎＰａｒｔＩ,ｉｔｗａｓａｐ ｐｌｉｅｄｔｏａｓｔｒａｔｉｆｉｅｄ ,ｒｅｃｔａｎｇｕｌａｒ,ａｎｄｔｗｏ ｌａｙｅｒｓｅａａｒｅａｗｉｔｈｓｔｅｐ ｌｉｋｅｔｏｐｏｇｒａｐｈｙｔｏｓｉｍｕｌａｔｅｔｈｅｇｅｎｅｒａｔｉｏｎａｎｄｐｒｏｐａｇａｔｉｏｎｏｆｉｎｔｅｒｎａｌｔｉｄｅｓ.Ｔｈｅｉｎｔｅｒｎａｌｔｉｄｅｖｅｌｏｃｉｔｉｅｓｏｆｔｈｅｕｐｐｅ… 相似文献
3.
In this study, a 3D idealized model of tidal flow, in which the tidal elevation and velocities are solved analytically, is developed. The horizontal eddy viscosity is neglected, and the vertical eddy viscosity used in the study is assumed to be independent of time and only varies as a parabolic function in the vertical direction. The analytical solution is obtained in a narrow rectangular bay, with the topography varying only across the bay. The model results are compared with the field observations in the Xiangshan Bay. The results show that the influence of varying vertical eddy viscosity mainly has two aspects. On one hand, it amplifies the magnitude of the tidal elevation, particularly the amplitude near the head of the bay. On the other hand, it adjusts the axial velocity profile, resulting in an obvious frictional effect. Furthermore, the tidal elevation and velocities are more sensitive to the magnitude of the eddy viscosity near the bottom than the structure in the upper water layer. 相似文献
4.
A continuously stratified nonlinear model is set up to study the impact of topographical character on the generation of internal solitary waves over a sill by tidal flow. One of the reasons why almost all of the generated internal solitary waves propagate westward in the northern South China Sea is explained. The model simulations describe the generation and propagation of internal waves well. When the strength of imposed barotropic tides and the water stratification stay unchanged, the steepness of the sill slope can control both (a) whether or not the waves induced over a sill by tidal flow are linear internal waves or nonlinear internal solitary waves, and (b) the amplitude of the internal solitary waves generated. If the steepness of the sill is asymmetric, the nonlinear internal solitary waves may be induced on the steeper side of the sill. These conclusions are supported by a numerical experiment with a monthly-mean stratification and an actual seafloor topography from the Luzon Strait. 相似文献
5.
mODUCTIONAsknowntoall,noulinearwavesaresomofthemostinterestingsubectsinthefieldofflnid~cs.ShallowwaterwavesarenotablefortheirirnPOrtanaPPlicationsinneaxshore,riveroudiow,lOngcanal,etc.AstheeqUaionsgovwhngwaterwavesarenonhnearitisveryallctilttoobtalntheirexatanalyticalsoluhons.SO,anuInberofaSyInPtOhcmethedshaVebousedinthePa8sevenddecades(JefferyandKawahara,1982;Debna,l994)tosohenoulinearwavs.AInOngthesemeththe,BoussineSq'stheorydescribingthebalanebetweenthenoallndtyanddispersion(Mei… 相似文献
6.
The layered model in Part I was used to simulate the internal tide in a stratified, two layer, and rectangular sea area with
step-like topography. The internal tide current velocities of the upper and lower layers and the interfacial elevations were
computed and the effect of the upper layer water depth and density difference were studied. Numerical experiments verified
that the model can correctly simulate internal tides. The model was also applied to the northwestern part of the South China
Sea to simulate the internal tides there with real topography. The distributions of internal tide amplitude in interfaces
were delineated.
Contribution No. 3590 from the Institute of Oceanology, Chinese Academy of Sciences.
Project 49676275 supported by NSFC and also supported by National Special Research Program 97-926-05-02. 相似文献
7.
The state-of-the-art OpenFOAM technology is used to develop a numerical model that can be devoted to numerically investigating wake-collapse internal waves generated by a submerged moving body.The model incorporates body geometry,propeller forcing,and stratification magnitude of seawater.The generation mechanism and wave properties are discussed based on model results.It was found that the generation of the wave and its properties depend greatly on the body speed.Only when that speed exceeds some critical value,between 1.5 and 4.5 m/s,can the moving body generate wake-collapse internal waves,and with increases of this speed,the time of generation advances and wave amplitude increases.The generated wake-collapse internal waves are confirmed to have characteristics of the second baroclinic mode.As the body speed increases,wave amplitude and length increase and its waveform tends to take on a regular sinusoidal shape.For three linearly temperature-stratified profiles examined,the weaker the stratification,the stronger the wake-collapse internal wave. 相似文献
8.
LIU Xianqing ZHANG Puyang ZHAO Mingjie DING Hongyan LE Conghuan LV Nan LUO Sheng 《中国海洋大学学报(英文版)》2022,21(1):39-48
The structure of an air-floating caisson is suitable for the major structure of caisson-type artificial islands.Thus,it has been rapidly developed and widely used in the exploration and development of oil and gas fields in shallow sea and intertidal zones.Air-floating transportation technology is one of the key technologies employed in this structure.In this paper,the factors influencing the dynamic response characteristics of air-floating caisson with multi-compartments(AFCMC)were studied using model tests.The length and the height of each air-floating structure in the model were 1.0 and 0.1 m,respectively.In addition,the 1:100 models with 6,8,and 10 compartments under regular waves were tested in the wave flume,respectively.In the experiments,the respective water depths were set at 0.2,0.3,and 0.4 m,and the corresponding drafts were 0.05,0.06,and 0.07 m.Results show that with the increase of draft,the heave natural period increased and the maximum amplitude of the heave motion decreased.Meanwhile,the pitch motion decreased at 6 and 8 compartments and increased at 10 compartments.As the water depth increased,the maximum amplitude and amplitude change of heave and pitch motions first increased and then decreased.However,several amplitudes close to the maximum amplitude appeared in the measured period at shallower water depth,thereby indicating the vertical movements of the structure enhanced under shallow water.The increase in the number of compartments reduced the vertical movements under 6.0 m draft,but it increased the vertical movements under 5.0 and 7.0 m draft.Thus,increasing the number of compartments has a limited capacity to improve the motion performance of the structure. 相似文献
9.
Boussinesq’s theory was used in this study on water waves entering shallow water showing that the spacial variation of the
wave amplitude is nonlinear, and is governed by the Duffing equation usually applied to describe nonlinear oscillation in
nature.
Contribution No. 3324 from the Institute of Oceanology, Chinese Academy of Sciences.
Project 49471276 supported by NSFC and the Ninth-Five-Year Key Project (KI952-s1-420) of the Chinese Academy of Sciences. 相似文献
10.
Depression and elevation internal solitary waves in a two-layer fluid and their forces on cylindrical piles 总被引：1，自引：0，他引：1
Both large amplitude depression and elevation internal solitary waves (ISWs) were observed on the continental shelf of the northwest South China Sea (SCS) during the Wenchang Internal Wave Experiment. In this study, we investigate the characteristics of depression and elevation ISWs based on comparisons between observational results and internal wave theories. It is suggested that the large amplitude depression wave is better represented by the extended Korteweg-de Vries (EKdV) theory than by the KdV model, whereas the large amplitude elevation wave is in better agreement with the KdV equation than with the EKdV theory. Wave-induced forces on a supposed small-diameter cylindrical pile by depression and elevation waves are also estimated using the internal wave theory and Morison formula. The wave-induced force by elevation ISWs is rarely reported in the literature. It is found that the force induced by the elevation wave differs significantly from that by the depression wave, and the elevation wave generally produces greater force on the pile in the lower water column than the depression wave. These results show that ISWs in the study area can present a serious threat to ocean engineering structures, and should not be ignored in the design of oil platforms and ocean operations. 相似文献
11.
瑞雷波法已在研究地球内部结构、近地表地球物理工程和超声无损检测等领域中获得了广泛应用,尤其是近年来瑞雷波法作为近地表场地表征新兴领域的前沿技术已成为国际学术研究与应用的热点。对国内外近地表弹性介质瑞雷波勘探的主要研究成果与进展进行了综述,通过对瑞雷波勘探现有的研究成果和进展密切追踪发现当前近地表瑞雷波勘探主要基于水平地表弹性水平层状介质模型,利用单分量瑞雷波相速度频散曲线单目标反演获得一维横波速度剖面和相关岩土力学参数。但是,该方法也存在着现有瑞雷波频散曲线反演极易出现模式误识别、现有单分量单目标瑞雷波反演未充分利用多分量信息、现有瑞雷波相速度反演未充分利用群速度传播特性、现有瑞雷波反演未充分利用质点椭圆极化振动特性等挑战性学术难题和不足。基于上述问题,建议未来近地表弹性介质瑞雷波勘探重点研究方向应集中在进行多模式表面波全速度谱反演研究、多站多分量表面波相速度多目标全速度谱反演研究、单站多分量表面波群速度多目标全速度谱反演研究和单站多分量表面波椭圆极化振动特性多目标反演研究。由此构建新的近地表多分量瑞雷波多目标全速度谱反演理论,引领多分量瑞雷波多目标反演学科前沿,拓展现有单分量瑞雷波单目标反演理论范畴,推动多分量瑞雷波高精度实用勘探技术的发展。 相似文献
12.
水库滑坡约束条件影响其运动过程的几何形态, 是滑坡涌浪预测的重要参数之一。为了探究约束条件对滑坡涌浪特征(波高、波幅与周期)的影响, 采用正交试验设计法开展了54组滑坡涌浪室内模型试验, 并基于统计学理论对约束散体和半约束散体的涌浪特征进行了分析。结果表明: 涌浪波周期基本不受滑体约束条件的影响; 而半约束散体模型的波高和波幅小于约束散体的波高和波幅, 半约束散体的初始涌浪波高约为约束散体的0.95倍, 半约束散体模型的最大波峰波幅约为约束散体模型的0.9倍。因此, 在开展滑坡涌浪快速预测时, 虽然滑体入水形态与破坏前形态差异巨大, 但基于滑坡初始几何形态参数对其初始涌浪波高和最大涌浪波幅的预测结果是偏安全的。研究结论可以为更准确地预测水库滑坡涌浪提供理论依据。 相似文献
13.
青岛台站重力固体潮和海潮负荷特征研究 总被引：1，自引：0，他引：1
选取青岛台站2012-01~2013-02 gPhone重力仪连续观测资料进行预处理和调和分析，获得其重力潮汐参数，并选取8个全球海潮模型对O1、K1和M2潮波进行海潮负荷改正。结果表明：1）8个主要潮波调和分析的振幅因子标准差均在2.6%之内，与理论潮汐模型值的差异也在3.0%之内；2）利用海潮模型对O1、K1和M2潮波进行改正能有效地降低残差矢量，观测残差负荷改正的有效性大致分布在30%~75%，全球海潮模型对青岛台站主要潮波的海潮负荷改正差别不大。 相似文献
14.
Seismic surges and landslides are both major secondary mountain hazards during an earthquake. This paper investigates earthquake- and landslide-induced composite surges through large-scale shaking table water tank model experiments. A series of tests were conducted for various initial water depths, peak ground accelerations, slide impact velocities, and slide volumes. Based on the results of the tests, the effects of these parameters on the maximum wave heights of the earthquake- and landslide-induced composite surges were analyzed. An amplification coefficient of seismic surges was defined, and the prediction equation for the amplification coefficient was developed through non-dimensional multiple linear regression analysis. Then, an empirical equation for the maximum wave heights of the composite surges was developed based on the amplification coefficient and Demirel’s method. This equation provides a calculation method for earthquake- and landslide-induced composite surge waves. 相似文献
15.
Feng Shizuo 《中国海洋湖沼学报》1984,2(2):177-187
Considerable scientific and practical interest exists in ascertaining the dynamic processes in shallow seas. This is especially
true for China having a vast area of shallow seas. To simulate the observed data and study the dynamical mechanism of waves
and currents in shallow seas a numerical model is developed in this paper. In view of the notable nonlinearity of shallow
sea waves and currents, and in order to solve the current distribution in the vertical direction, and to examine the effect
of variable eddy viscosity, the model proposed is a three-dimensional nonlinear one with variable eddy viscosity. The eddy
viscosity can be considered as a physically acceptable arbitrary function of depth, which is realized in terms of a Sturm-Liouville
System. The currents are expressed by using the eigenfunctions satisfying the Sturm-Liouville System just mentioned. A boundary-value
problem (or an initio-boundary-value problem) of free surface elevation is derived. And then, the application of the proposed
shallow sea model to nonlinear tides, ultra-shallow water storm surges and steady circulation is given, respectively. Finally,
a generalized linear law between the bottom friction and the transport is derived.
This paper was presented at the Joint Oceanographic Assembly (J.O.A.) held at Halifax, Canada, August 2–13, 1982, and included
in “Poster Abstract” Vol. I. 相似文献
16.
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17.
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18.
NUMERICAL STUDY OF THE INFLUENCE OF WAVES AND TIDE-SURGE INTERACTION ON TIDE-SURGES IN THE BOHAI SEA
Abstract The author‘s combined numerical model consisting of a third generation shallow water wave model and a 3-D tide-surge model with wave-dependent surface wind stress were used to study the influence of waves on fide-surge motion. For the typical weather case, in this study, the magnitude and mechanism of the influence of waves on tide-surges in the Bohai Sea were revealed for the first time. The results showed that although consideration of the wave-dependent surface wind stresses raise slightly the traditional surface wind stress, due to the accumulated effects, the computed results are improved on the whole. Storm level maximum modulation can reach 0.4 m. The results computed by the combined model agreed well with the measured data. 相似文献
19.
《中国海洋大学学报(英文版)》2007,(1)
1 Introduction Today, maneuvering the draghead of a trailing suction hopper dredger (TSHD) on a predetermined spot is an operation that demands an increasing degree of accuracy (Cornelis, 1983). As a self-propelled, self-loading and self-discharging seagoing or inland waterway vessel with one or more flexible suction pipes equipped with special dragheads, the TSHD has a wide application area and is therefore called the workhorse of the dredging industry (Ni, 2004). The swell compensator, c… 相似文献
20.
CHC Trailing suction hopper dredgers (TSHD) have been widely used in dredging industry. In order to simulate the dredging
process accurately, a mathematical model for a swell compensator used in TSHD is proposed, and a friendly simulation model
based on the Automated Dynamic Analysis of Mechanical Systems (ADAMS) is built to test and validate the mathematical model
for the swell compensator. The factors influencing the dynamic behavior of the TSHD suction pipe system, such as the motion
of the vessel in an unquiet situation with different water current velocities, seabed profiles, seabed soil hardness and the
forces acting on the suction pipe system, have been taken into consideration. The simulation results show that they fit in
with the operating practice qualitatively. 相似文献