围填海工程对渤海湾风浪场的影响   总被引：4，自引：0，他引：4  

赵鑫  孙群  魏皓 《海洋科学》2013,37(1):7-16

为了深入了解围填海工程对波浪场特别是风浪场的影响,针对10 a 围填海工程对渤海湾地形岸线的改变,将 SWAN(Simulating Waves Nearshore)海浪数值模式应用到渤海湾,讨论了人类大工程对渤海湾风浪场的影响.采用欧洲气象中心每天4次的风场资料作为驱动,模拟渤海湾2000年和2010年的风浪场,着重分析岸线变化显著的3个港口工程(曹妃甸、天津港和黄骅港)附近海域的波浪要素变化.研究结果表明,工程建筑物存在后,有效波高呈减小趋势,港池和潮汐通道内的有效波高减小幅度较大.港口地理位置和海底地形也与岸线变化共同影响着港口附近海域的波浪场分布.围填海工程对波浪有效波高及周期影响的程度不大,有效波高减小值在0.2 m 以下,周期几乎不变.  相似文献   

Hydrodynamic behavior of a straight floating pipe under wave conditions   总被引：2，自引：0，他引：2  

Yucheng Li  Fukun Gui  Bin Teng 《Ocean Engineering》2007,34(3-4):552-559

This paper examines the hydrodynamic behavior of a floating straight pipe under wave conditions. The main problem in calculating the forces acting on a small-sized floating structure is obtaining the correct force coefficients C_n and C_t, which differ from a submerged structure. For a floating straight pipe of small size, we simplify it into a 2D problem, where the pipe is set symmetrically under wave conditions. The force equations were deduced under wave conditions and a specific method proposed to resolve the wave forces acting on a straight floating pipe. Results of the numerical method were compared to those from model tests and the effects of C_n and C_t on numerical results studied. Suggestions for the selection of correct C_n and C_t values in calculating wave forces on a straight floating pipe are given. The results are valuable for research into the hydrodynamic behavior of the gravity cage system.  相似文献   

Bailard's sediment transport formulation in shelf sea conditions: comparison with observations using a clustering technique     

Johan van der Molen   《Coastal Engineering》2003,47(4):399-412

A previously published wave-averaged version of Bailard's sediment transport formulation, intended for use in a numerical model of shelf sand transport, is compared against available field observations from literature. The objective was to test the performance of the transport relation over the wide range of hydrodynamical conditions that can occur at sea. A modified data analysis method was used to assess the reliability of the field observations. The modification consists of a method to cluster the data into classes to enable statistical analysis. The sediment transport formulation is part of the classification method. The method is in principle also suitable to reduce the size of data sets of non-cohesive sediment transport obtained with modern electronic equipment. The results show that the quality of the published field observations is fair, and that the wave-averaged Bailard formulation performs well for low and medium transport regimes in both currents and waves. For those conditions, it yields a slight overprediction of the transports, and a nearly uniform behaviour as a function of the conditions. The formulation underestimates transport rates for very high flow velocities in absence of waves, which is in agreement with earlier findings. The present version of Bailard's wave averaged sediment transport formulation is suitable for computing the local transport rates of fine to coarse sand on continental shelves in conditions ranging from small currents to moderate currents combined with non-breaking waves.  相似文献   

山东半岛海岸地貌与波浪、潮汐特征的关系     

崔金瑞  夏东兴 《海洋科学进展》1992,(3)

本文通过山东半岛海岸地貌类型与沿岸波浪、潮汐发生学关系的对比分析,引入浪潮作用指数 K,K=2.5×(H/R),H 为平均波高,R 为平均潮差.K>1时,海岸地貌演变的动力以波浪作用为主,海岸极少发育潮汐叉道和落潮三角洲,但连岛坝发育较好;K<1时,海岸地貌演变的水动力以潮汐作用为主,落潮三角洲、潮汐叉道较发育;K 值接近于1时,发育潟湖等过渡海岸地貌类型.  相似文献   

Modeling of tropical cyclone winds and waves for emergency management   总被引：5，自引：0，他引：5  

Amal C. Phadke  Christopher D. Martino  Kwok Fai Cheung  Samuel H. Houston   《Ocean Engineering》2003,30(4):5039-578

This paper compares three commonly used parametric models of tropical cyclone winds and evaluates their application in the wave model WAM. The parametric models provide surface wind fields based on best tracks of tropical cyclones and WAM simulates wave growth based on the wind energy input. The model package is applied to hindcast the wind and wave conditions of Hurricane Iniki, which directly hit the Hawaiian Island of Kauai in 1992. The parametric wind fields are evaluated against buoy and aircraft measurements made during the storm. A sensitivity analysis determines the spatial and spectral resolution needed to model the wave field of Hurricane Iniki. Comparisons of the modeled waves with buoy measurements indicate good agreement within the core of the storm and demonstrate the capability of the model package as a forecasting tool for emergency management.  相似文献   

Observations and measurements of wave-induced drift of surface inextensible film in deep and shallow waters     

Adrian Wing-Keung Law  Guoxing Huang 《Ocean Engineering》2007,34(1):94-102

The present study investigates the drift of two-dimensional floating surface films by both deep and shallow water waves in the laboratory. The focus is on the observations and measurements on the drift behavior and to clarify some outstanding issues. Thin polyethylene sheets with reflective markers were attached to simulate the inextensible surface films. Upon the initiation of a wave train, two infrared cameras recorded continuously the instantaneous position of the markers at 50 Hz. The temporal variation of the drift velocity was then determined by processing the recorded data. In all experiments, the drift velocity increased quickly in the beginning and reached a quasi-steady mean value. The magnitude of the surface drift typically increased with the longitudinal length of the polyethylene sheet until the sheet length was approximately the same as the wavelength. Lengthening the sheet length further did not lead to significant changes in the drift velocity. Under the shallow water condition, the wave-induced drift velocity increased linearly with the Ursell number and with a lower water depth.  相似文献   

Hydrodynamic interactions between two ships advancing in waves   总被引：3，自引：0，他引：3  

Gung-Rong Chen  Ming-Chung Fang 《Ocean Engineering》2001,28(8)

In this paper the hydrodynamic problems between two moving ships in waves are analyzed using a three-dimensional potential-flow theory based on the source distribution technique. The potential is presented by a distribution of source over the ship hull. The corresponding Green functions and their derivatives can be easily solved numerically by using the series expansions of Telste and Noblesse's algorithm for the Cauchy principal value integral of unsteady flow. The numerical solution is evaluated by applying the present method to two pairs of models and compared with experimental data and strip theory. From the comparisons, it shows that the hydrodynamic interactions are generally important. In the resonance region, the hydrodynamic interaction calculated by the 3D method is more reasonable, which is not so significant as that by the 2D method. The technique developed here may serve as a more rigorous tool to analyze the related problems of two ships doing underway replenishment in waves.  相似文献   

Molecular mixing layers in stellar outflows     

S. D. Taylor  A. C. Raga 《Astrophysics and Space Science》1995,233(1-2):139-144

High velocity jets from young stars interact with the surrounding molecular environment and molecular outflows quite possibly are the result. This interaction can take place through the formation of a turbulent mixing layer. Models have been constructed (following Cant/'o and Raga) of a plane mixing layer in the boundary between a high velocity, atomic wind (i.e., the stellar jet) and a stationary, molecular environment, computed considering a detailed chemical network.The chemical composition of the mixing layer initially corresponds to the direct mixture of the (atomic) jet and (molecular) environmental material. However, we find that the mixing layer is hot (with temperatures exceeding 10⁴ K), and the surprising only partial dissociation of H₂ means that a number of molecules are either created or survive in the high velocity gas. This contrasts with the slower, cooler flows that have tended to be termed a molecular outflow.The emission from such atomic jet/molecular environment mixing layers is dominated by emission in the rotational and vibrational lines of H₂. As a result of the high temperatures and velocities (ranging from zero to the jet velocity) of these mixing layers, the predicted H₂ emission line spectrum has interesting characteristics.  相似文献   

Wave climate and long-term changes for the Southern North Sea obtained from a high-resolution hindcast 1958–2002     

Ralf Weisse  Heinz Günther 《Ocean Dynamics》2007,57(3):161-172

An analysis of the extreme wave conditions in 1958–2002 in the North Sea as obtained from a regional model hindcast is presented. The model was driven by hourly wind fields obtained from a regional atmosphere model forced with reanalysis data from the National Center for Environmental Prediction (NCEP/NCAR). Furthermore, observed sea ice conditions from the Norwegian Meteorological Institute have been accounted for in the simulation. It is shown that the model is capable of reproducing extreme wave height statistics at a reasonable degree of approximation. The analysis of severe wave height events reveals that for much of the Southern North Sea, their number has increased since the beginning of the simulation period (1958), although the increase has attenuated later and leveled off around about 1985. On the other hand, the intensity and duration of severe wave height events decreased within the last few years of the simulation so that annual 99%-ile wave heights have also reduced since about 1990–1995. For the UK North Sea coast, a different behavior was found characterized by a reduction in severe wave conditions over much of the hindcast period.  相似文献   

Interactions among waves,current, and mud: Numerical and laboratory studies     

Zi-Dan Zhao  Ji-Jian Lian  John Z. Shi 《Advances in water resources》2006

Interactions between waves, current, mud and turbulence are very complicated in the coastal and estuarine turbid waters. It is still necessary to improve our understanding of the fundamental physical processes governing the cohesive sediment transport in the coastal and estuarine waters. A numerical model is developed to study the interactions among waves, current, and mud. An eddy viscosity model for wave and current is proposed in order to close the equations of wave motion or of current motion in a combined flow, respectively. The equations of mud transport are derived based on the visco-elastic properties of mud. Coupling the equations of wave motion or of current motion for water layer with those of mud layer can give (1) wave height; (2) distributions of current velocities in the water layer; (3) distributions of transport velocities at the water–mud interface; and (4) distributions of mass transport velocities within the mud layer. These modeled results are in a reasonable agreement with experimental results. Results suggest that (1) the rate of wave attenuation increases in the opposing currents (currents against in the direction in which the waves propagate) and decreases in the following currents (currents in the same direction as that in which the waves propagate); (2) the opposing currents would have more significant effects on the rate of wave height attenuation than the following currents; (3) the effect of current on the rate of wave attenuation on the muddy bottom is larger than that on the rigid bottom; (4) mud transport rate increased in the following currents but decreased in the opposing currents; and (5) the rate of wave height attenuation on the mud bottom is one order of magnitude larger than that on the rigid bottom.  相似文献