【作者】 王金华；

【导师】 沈永明；

【作者基本信息】 大连理工大学 ， 港口、海岸及近海工程， 2011， 博士

【摘要】 波流相互作用对水动力、水环境有重要影响,许多学者对这一领域进行了研究。采用非结构网格可以很好拟合复杂的岸线边界及对重点研究区域进行局部加密。目前基于非结构网格的完全波流耦合模型研究较少。本文在前人的研究工作基础上,建立了非结构波流完全耦合数值模型,并对建立的模型进行了一系列验证及应用研究。建立了一个并行的非结构网格波浪数值模型,模型遵守波能守恒方程,考虑了浅水效应、折射、波能耗散等影响因素。对建立的波浪模型与非结构有限体积水流数值模型进行完全耦合,耦合过程包括三维辐射应力、斯托克斯漂流、波浪耗散对紊流方程的作用等。通过几个例子对建立的模型进行了验证,着重研究了“卡特里娜”飓风引起的风暴潮,模拟的波要素和水位与实测值吻合较好。通过几组试验研究了波浪效应对水位的影响,试验表明辐射应力、波浪导致的表层应力对水位影响较大,波浪导致的底层应力对水位影响较小,模型包含波浪的作用对预报风暴潮引起的水位变化至关重要。通过拉格朗日方法研究了渤海冬夏季环流及潮、风、海气热交换和入海径流对渤海环流的影响。研究表明：粒子输移存在明显的三维结构；三个湾内水体输送均较小、表底层相差不大；渤海夏季环流强度较冬季强；由风引起的拉格朗日水体输送对渤海环流影响较大；温盐环流对水体输送的影响主要在夏季,在冬季,影响可以忽略；河流只对河口附近环流结构有影响；夏季,与热盐、风相比潮流对拉格朗日水体输送贡献较小；只考虑单分潮的作用将不能反映渤海的实际环流情况。建立了三维溢油模拟系统用于预报海上溢油的轨迹和最终归宿。模型包括水流与输移-归宿两个模块。水流模块采用非结构有限体积、波流耦合数值模型。在输移-归宿模块中采用粒子追踪法模拟油膜的输运。油的迁移过程包括对流、扩展、紊动扩散、附着在岸边、沉降到海底等；转化过程包括挥发、溶解、乳化等。应用建立的溢油模拟系统对渤海海峡发生的突发性溢油事故进行了模拟。对大伙房水库的平均滞留时间、水龄及水质进行了数值模拟研究。研究表明：在高、平均、低流量情况下,从上游释放的示踪物质滞留时间分别为125d、236d和521d;水龄随着上游流量变化而变化;在垂向上表层水龄较底层大,越往下游表底层水龄相差越小；水库中由温度变化引起的密度流对水龄分布具有重要影响,是引起表底层水龄分布异同的主要原因；通过敏感度分析检验了参数对水质模型的影响,模型成功再现了水质变量在时间和空间上的分布。模型可为水库的工程设计及管理提供帮助。更多还原

【Abstract】 Recognizing the important role of wave-current interaction played in hydrodynamic and water environment, scientists have become increasingly interested in establishing a regional predicting system that could couple three-dimensional ocean models with wave models. Using unstructured meshes provides an accurate fitting of the irregular coastal boundary, with refined grid resolution in regions of interest and not elsewhere. In this study, an unstructured three-dimensional fully coupled wave-current model is developed. Several applications are presented to evaluate the developed model.A parallel, unstructured grid, parametric wind-wave model is firstly developed with the intention of coupling to three-dimensional unstructured grid ocean circulation models. The model is derived from a conservation of energy flux formulations. In the model, the shoaling, refraction, and wave dissipation, as well as exchange of current and stokes drift momentum effects are considered. Then, the existing Finite-Volume Coastal Ocean Model is modified to couple with the wave module. The couple procedure includes depth dependent wave radiation stress terms, Stokes drift, vertical transfer of wave-generated pressure transfer to the mean momentum equation, wave dissipation as a source term in the turbulence kinetic energy equation, and mean current advection and refraction of wave energy. Several applications are presented to evaluate the developed model. In particular the wind and wave-induced storm surge generated by hurricane Katrina is investigated. The obtained results have been compared to the in situ measurements with respect to the wave heights and water level elevations revealing good accuracy of the model in reproduction of the investigated events. Several runs were carried out to analyze the effects of waves. The experiments show that among the processes that represent wave effects, radiation stress and wave-induced surface stress are more important than wave-induced bottom stress in affecting the water level. The hurricane Katrina simulations showed the importance of the inclusion of the wave effects for the hindcast of the water levels during the storm surge.Seasonal circulation of the Bohai Sea (BS) in 1992 was investigated using Lagrangian particle tracking method. The transport of particles has three-dimensional (3D) structure in the BS. Compared with central Bohai and Bohai Strait, the differences of particles’transportation between surface and bottom layer in three bays are small. The circulation in the summer is stronger than that in the winter, with the average residual velocity in the surface layer being about 3.7 cm/s during the summer while only 1.8 cm/s during the winter. Using the same model, several well-designed numerical experiments were performed to investigate the effect of oceanic tide, river discharge, wind stress and thermal stratification on the circulation. It is shown that winds play an important role in the circulation of the BS during both the winter and the summer. Density circulation is important during the summer; however, it is negligible during the winter. River runoff only affects the area around the river mouth. Compared with wind and thermohaline effect, the contribution of tides is small during the summer, and the circulation under only M2 tidal constituent could not reflect the actual circulation of the BS.A three-dimensional integrated model is developed for simulating transport and fate of oil spills in seas. The model contains two main modules, flow and transport-fate modules. The flow module uses an unstructured finite-volume wave-ocean coupling model. In the transport-fate module the oil dispersion is solved using a particle-tracking method. The model simulates the most significant processes that affect the motion of oil particles, such as advection, surface spreading, evaporation, dissolution, emulsification and turbulent diffusion as well as the interaction of the oil particles with the shoreline, sedimentation and the temporal variations of oil viscosity, density and surface tension. This model has been applied to simulate the oil-spill accident in the BS.A three-dimensional hydro-eutrophication model was implemented to compute average residence time, water age and water quality in the Dahuofang Reservoir, China. Residence time estimations yield a broad range of values depending on the position. The average residence time for a tracer placed at the head of the reservoir under high-, mean-, and low flow conditions was found to be about 125,236 and 521 days, respectively. The age simulation reveals that the age distribution is a function of the freshwater discharge. In the vertical, the age of the surface layers is larger than that of the bottom layers and age difference between the surface and bottom layers decreases further downstream. The density-induced circulation plays an important role in the circulation in the reservoir, and can generate vertical age distribution in the reservoir. Sensitive of the parameters has been analyzed to decide which process would affect the water quality in the simulation. Water quality verification suggested the model successfully computed the temporal cycles and spatial distributions of key water quality components. The model could be used as a tool to guide physico-biological engineering design or management strategies for Dahuofang Reservoir.更多还原