【作者】 余志祥；

【导师】 赵雷；

【作者基本信息】 西南交通大学 ， 结构工程， 2011， 博士

【摘要】 随着国内高速铁路建设热潮,各种造型新颖、布局复杂的大型交通枢纽客站陆续建成。这些客站采用了多种新型结构形式,风荷载成为其正常使用及安全运营的主要影响因素之一。外观造型及站场布局影响致使铁路客站产生了复杂的风致作用,站场建筑群的干扰影响进一步加剧了这种复杂性。目前,国内外对高速铁路客站风致作用研究较少,已有研究多局限于具体工程应用,缺少对其风致作用的形成机理、变化规律进行深入探讨。因此,对铁路客站风致作用展开深入系统地研究具有重要的工程意义和学术价值。本文基于CFD数值模拟、风洞试验和非定常流固耦合(FSI)理论,研究了大气边界层下铁路客站建筑的基本风荷载特性和风场特征,揭示了平均来流及脉动来流条件下站场建筑的风致作用形成机理及变化规律,并将研究成果应用于实际工程的抗风设计。论文完成的主要研究内容如下：首先,对计算风工程理论进行了梳理,搭建起数值风洞模拟的基本方法框架和参数体系。同时,基于CFX的全隐式瞬态时间步进算法,提出了准稳态时步逼近求解技术(QSMA:Quasi-Steady State Marching-on in time Approximation Techniques),通过数学推导证明了这种技术在时间离散格式上的稳定性、误差传递的趋零特性,给出了与之配套的多目标收敛监测、数值稳定控制参数,并与Murakami-3D立方体模型的隐式稳态模拟结果进行了比较,证明了其有效性。这种技术降低了瞬态算法求解稳态问题的时间步长及容差限制,和传统稳态算法相比,计算消耗没有增加,但由于利用了瞬态控制方程求解,针对复杂建筑风场数值模拟的收敛性增强。第二,基于准稳态时步逼近技术,结合TTU模型实测数据,对EARSM用于建筑数值风洞模拟的计算控制参数进行了系统研究,包括流场自平衡检验、网格形式、湍流模型、流场尺度、边界条件、对流项格式、近壁区网格△y值等。通过系统的校准研究,搭建起基于EARSM的数值风洞模拟计算参数框架。第三,基于几何拓扑分析原理,提出了铁路客站建筑群风荷载预测的模化特征体分析方法,结合12组特征体模型的试验数据,采用EARSM和准稳态时步逼近求解技术进行了数值风洞模拟,研究了风向角、屋面坡度、结构高度、屋面拓扑特征、结构开敞与否、矢跨比对风荷载形成机理以及风场特性的影响。将该方法用于实际铁路客站风荷载分析并与规范相似特征相比较,结果表明方法的实用有效。第四,设计了4组参数性风洞试验模型,考虑建筑群风场干扰影响、雨棚是否开缝、二期扩建、匝道阻塞影响,进行了风洞试验,研究了铁路客站的风场干扰影响规律。基于几何拓扑分析原理,将铁路客站简化为三种典型的模化布局特征体模型。结合数值风洞模拟、模化特征体分析方法以及试验数据,对站台区雨棚开缝率、主站房与站台雨棚的高度比、主站房入口大悬挑雨棚俯仰角等风场干扰影响因素进行了深入研究,给出了铁路客站风场干扰影响的主要变化规律。最后,采用AR法和WAWS法编制了多点三维相关脉动风速模拟程序、脉动风速散度修正程序,构建了非定常流固耦合(FSI)分析的脉动入流边界。基于TTU实测数据对人工模拟脉动风场进行了校准分析。基于自编目标概率法程序研究了脉动风场的统计特性。基于任意拉格朗日-欧拉(ALE)坐标下的有限体积法,采用大涡模拟(LES)求解Navier-Stokes方程,构建了大跨度弦支结构雨棚的气动分析模型；结合大跨度弦支结构雨棚的非线性瞬态动力学模型,采用ALE方法处理结构与风场的运动边界,实现了结构动力学与计算流体力学的结合,构建了结构-风场耦合分析模型；研究了不同风向角下大跨度弦支结构雨棚动力响应的频谱特征、脉动风压分布规律、预张力对弦索振动特性的影响、脉动风对弦索张力退化的影响等,可为工程设计提供参考。更多还原

【Abstract】 With the rapid development of high-speed railway, a number of large train stations with various layouts have been built in recent years. Wind load has become a serious concern on normal use and safe operation of train stations where some new structures are adopted. Complicated appearance and layout of stations result into complex wind-induced action, and the influence of architectural complex makes it more serious. At present, very few study has been reported on the wind-induced action of the train stations at home and abroad. There is a lack of the researches in the mechanism and variation rule of wind-induced action of the train stations, except for some researches on specific projects. Therefore, it has important engineering significance and academic value to investigate the wind-induced action to train stations in detail.The characteristics of wind field of train station in the atmospheric boundary layer are studied based on CFD simulation, wind tunnel test and unsteady FSI theories. The mechanism and variation rule of wind-induced action under mean and fluctuating wind are revealed and then applied to practical wind resistant design. The main contents of the thesis are summarized below.Firstly, CFD theory and its latest achievements are sorted out to establish a frame including basic techniques and parameters in numerical wind tunnel. Quasi-steady State Marching-on in time Approximation method (QSMA) is proposed based on full implicit marching-on in time method in CFX. The stability of time discretization scheme and tendency to zero during error transfer are proved mathematically. The suggested Multi-goals monitoring method and control paramters of numerical stability coordinated with QSMA are provided. Besides, the validity of QSMA is testified by comparing with steady-implicit simulation results of Murakami-3D cube model. The analysis proves that the suggested QSMA-trans algorithm can decrease the restriction of the time spacing and convergence tolarence in the solution of steady state problem by means of Transient algorithm. Compared with the traditional steady-state algorithm, the suggested algorithm improves convergence in complicated numerical simulation for using transient N-S equations without additional consumption.Secondly, The control parameters of EARSM that are applicable to numerical wind tunnel simulation are studied in detail based on QSMA-transient method and TTU field model tests, including self-balance checking of the wind field, grid patterns, turbulence models, length scale of the wind field, boundary conditions, convection schemes,△y of grid near the wall, inflow velocity profiles and so on. The parameter system of EARSM involving in numerical wind tunnel simulation is provided on comprehensive verifications.Thirdly, the Characteristic-shape analysis method is proposed to predict the wind field of train station based on geometry topology analysis. According to the wind tunnel test of twelve typical Characteristic-shape models, EARSM and QSMA-transient method are employed in numerical wind tunnel simulation. The influence of wind directions, topological features on the generation of wind field and its characteristics are investigated. The wind field of practical projects is analyzed by using the Characteristic-shape method, comparing with Characteristic-shape in the codes, which indicates that this method is practical and effective.Fourthly, four models are designed for wind tunnel test taking the influence of canopy slotting, second period of extension and ramps blocking into account, to study the interference effect of wind field. The structure is discretized into three types of typical Characteristic-shapes based on geometry topology analysis. The wind field influence factors of canopy slotting ratio, large cantilevered canopy pitch of the main station building and the height ratio of main station and platform canopy are investigated and the variation rule of wind field is revealed comprehensively combining numerical method, Characteristic-shape analysis method and test research.Lastly, the calculation schemes for 3D relevant fluctuation wind modeling by using AR and WAWS methods, and the free divergence operation are coded. The inflow boundery condition of unsteady FSI analysis is provided to calibrate the artificial simulated wind field based on the TTU test results. The statistical properties of fluctuation wind field are researched by the self-compiling program on target probability method. The LES, as well as Finite Volume method introducing Arbitrary Lagrangian-Eulerian scheme, is employed in solving the Navier-Stokes equation, to build the aerodynamic model for train station with large span cable-supported structure canopy. The FSI model whose boundary conditions is derived from the ALE scheme is set up in combination with nonlinear transient dynamic model of large span cable-supported structure canopy, to achive the integration of CSD and CFD. The spectrum characteristics, fluctuation wind pressure distribution, dynamic response of the cable and the influence of fluctuation wind on the tension stiffness degradation of large span cable-supported structure canopy in different wind directions are studied. The conclusions can be provided for reference in practical design.更多还原