Wind Loads And Fluid-structure Interaction For Large High-speed Train Stations

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,â–³y 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.