【作者】 梁丙臣；

【导师】 李华军；

【作者基本信息】 中国海洋大学 ， 港口、海岸及近海工程， 2005， 博士

【摘要】 海岸、河口区与人类经济、生活等各个方面息息相关,对人类有着非常重要的作用。海岸、河口区是陆海交界地带,陆地海洋相互作用显著,因此存在着很多的问题,其中对工程界来讲非常重要的一个问题就是泥沙问题,泥沙所引起的岸滩演变、港口航道的淤积、水动力环境的改变等等。针对海岸工程中泥沙问题的普遍性、复杂性,本文作者基于水动力-生态耦合模式COHERENS发展了一套三维水动力-悬浮泥沙耦合模型COHERENS-SED,并且考虑到海岸、河口区波流相互作用比较显著,本文将水动力-悬浮泥沙耦合模式COHERENS-SED与物理上先进的第三代波浪模式SWAN联合,最终发展了波流联合作用下的三维水动力-悬浮泥沙耦合数学模型并将其成功的应用于黄河三角洲滨海区的潮流和悬浮泥沙输运规律的研究。由于研究区域黄河三角洲滨海区有着较高悬沙浓度的存在,本文引入了悬浮泥沙对湍流的衰减作用以及近底层湍流产生、耗散及浮力破坏的平衡假说,并根据该平衡假说推导出了单方程κ—ε湍流封闭模式近底层内的湍流能量平衡表达式。对于波浪对水流的影响,本文在水动力模型中引入波浪依赖的表面风应力的影响、波浪影响下的底部剪切应力以及波浪产生的辐射应力影响并针对这些影响进行了数值分析。根据底床沉积物特性沿垂直方向变化以及水平方向变化的特点,开发了能够处理分层、分区域底床处理模型,从而能够较好地反映现场底床沉积物实际分布情况。本文的主要工作及创新点体现在: 一、在水动力模块,本文对COHERENS作了如下发展与完善: ① 底床面处的波流相互作用引入了波浪传播方向与流方向之间夹角的影响,而原模式中则认为这两个物理过程的方向是一致的,这一点与实际有时存在更多还原

【Abstract】 Coastal and estuary regions are such regions where the interaction between land and sea is obvious and the sediment becomes a big problem for coastal engineering. Coastal and estuary regions are characterized by intensive interaction between wave and current. Moreover, these regions are of great economic significance to mankind. Therefore, the simulation of sediment with wave and current as well as their mutual interactions in coastal and continental shelf waters has great economic value. In this dissertation, a three dimensional suspended sediment model is setup and is coupled with the combination of COHERENS and SWAN. In the end, a coupled hydrodynamic-sediment model is obtained and is adopted to simulate three dimensional current and suspended sediment of Huanghe delta. The damping function of suspended sediment on turbulence and the equilibrium assumption of turbulence are accounted for in coupled three dimensional hydrodynamic-sediment model. The turbulence energy expression of one equation turbulence close model k — ε is derived and adopted as the boundary condition of turbulence energy. Wave dependent surface drag coefficient, wave induced surface mixing length, wave-enhanced bottom stress and radiation stress are introduced into the coupled model and are analyzed through numerical experiments. Moreover, a bed model being able to stand for horizontal or vertical variant bed properties is setup in the present work, which is reasonable to the practical situation of field bed.The major contents in this dissertation are shown as following:I AS for hydrodynamic model COHERENS, the works of this dissertation are as follows: The introduction of the angle between current direction and wave propagation direction into COHERENS; Accounting for sediment damping function in turbulence close model; Abandon the well-known equilibrium between turbulence production and dissipation near the bottom and adopt the equilibrium assumption betweenturbulence production, dissipation and buoyancy induced destruction. According to the assumption, the expression of bottom boundary conditions for k - e is derived;> Accounting for the breaking wave induced surface mixing length in calculation of the mixing length;> Introduction of wave dependent surface drag coefficient;> Introduction of radiation stress;II Combine COHERENS and the third generation wave model SWAN and account for the influences of surface elevation and current velocity on wave calculation.III Setup and develop the numerical model of three dimension suspended sedimentwith wave and current co-existing;IV Discover the existence of three dimensional structures of shear front in Yellowdelta. The shear front of top and bottom layer show some obvious differences in tidal phase, duration and strength between each other, which can be attributed the difference of tidal phase and effects of river discharge.更多还原