孤立波作用下排柱附近水动力学特性数值研究

发布时间：2018-04-03 10:45

本文选题：孤立波　切入点：排柱　出处：《长沙理工大学》2015年硕士论文

【摘要】：排柱式建筑物在近海工程中的应用越来越广泛,而对于其在极端波况条件下附近水动力特性的研究目前仍较少,且主要以物理实验模型为主,未能完全获得模型附近的水动力特性信息。本文利用OpenFOAM开源程序包作为数值模拟工具,基于不可压缩Navier-Stokes方程,利用修正体积分数法捕捉自由液面,并耦合分离涡紊流方法中的Spalart-Allmaras DDES模型,建立孤立波与排柱间相互作用的三维水动力数学模型。通过开展相应的物理模型实验,获得排柱模型附近准确和完整的水动力特性信息,并以此对数学模型的可靠性进行验证。之后本文对非破碎孤立波作用下排柱和单柱、不同间隙比条件下排柱和破碎孤立波作用下不同排柱模型位置等条件下模型附近的水动力特性进行数值模拟研究,对比分析各工况条件下自由液面、水流结构、动水压强和波浪力等水动力特性的变化规律,探讨模型附近的能量耗散机理和受力特性,为今后单排圆柱式建筑物在近海工程的实际应用提供一定的理论参考。通过对比实验和数值计算结果,发现数值模型可以准确模拟孤立波与排柱相互作用过程中水动力特性的变化,能够精确捕捉到模型附近自由液面复杂的三维特征、间隙内高速水流的分离现象和柱后大尺度的尾涡结构。排柱附近的水动力特性变化规律相比单柱模型更为复杂,自由液面三维特征显著,间隙内排柱表面出现较强的水流分离现象,尾涡尺度和紊动强度均大于单柱。间隙比的不同直接影响到间隙内水体的流速大小,导致柱后水流的紊动特性出现不同,能量耗散差异明显,从自由液面上表现为排柱模型不同的消波性能。破碎点位置附近孤立波作用下排柱附近的水动力变化的复杂程度和能量耗散机理与非破碎波下相比明显不同,作用过程中耦合了建筑物的阻水作用和波浪的浅水波变形特征,水动力特性变化具有明显的涌波作用特征。
[Abstract]:Row type building application in offshore engineering more and more widely, and in the dynamic characteristics of water near the extreme wave condition is still less, and the physical experimental model, not completely get information hydrodynamic characteristics near the model. This paper uses the OpenFOAM open source package as a numerical simulation tool, can not compression based on Navier-Stokes equation, the modified volume fraction method to capture the free surface, and the Spalart-Allmaras DDES model of turbulent vortex separation coupling method, a three-dimensional hydrodynamic model of interaction between solitary wave and row. By carrying out the corresponding physical model experiment, obtain the row model near the accurate and complete information and the dynamic characteristics of water. The reliability of the mathematical model is verified. After the non broken columns and single column solitary wave under the conditions of different clearance ratio Columns and numerical simulation of the hydrodynamic characteristics of broken model near the solitary wave under the action of different row position under the condition of model, comparative analysis of the flow structure of free surface, under different working conditions. The variation of hydrodynamic characteristics of hydrodynamic pressure and wave force, to investigate the energy dissipation mechanism model nearby and force characteristics for single row cylindrical buildings provide a theoretical reference for practical application in offshore engineering. By comparing the experimental and numerical results, the numerical model can accurately simulate the changes of solitary waves and the interaction process of dynamic characteristics of water columns, can accurately capture the 3D model feature near the free surface complex, large scale vortex structure the gap in high-speed flow separation and post column row. Near the water dynamic characteristics compared with the single column model is more complex, the free surface three Dimensional characteristics and columns appear on the surface of strong flow separation gap, tail vortex and turbulence intensity were higher than single column. The flow velocity in the different water gap to directly affect the ratio of the gap, leading to turbulence characteristics of different column, the energy dissipation difference is obvious, from the performance of the free surface is row model of wave dissipation performance. Different crushing complexity of the point position near the isolated hydrodynamic changes near the wave row and the energy dissipation mechanism and non breaking wave under markedly different role in the process of building the coupling shallow water blocking effect and wave deformation characteristics, changes of hydrodynamic characteristics with wave function obvious characteristics.

【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TV131.2

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