The Analysis Of Wind Load And Characteristics Of Flow Around High-rise Buildings With CFD

Research on the characteristics of wind flow field around high-rise buildings isimportant to improve the wind environment of building and groups of buildings, raisethe comfort for residence. Because of high cost and difficulty of measurement, it isvery difficult for the spot measure actually carry on the study of wind field around ahigh-rise building, wind tunnel experiments is also difficult to be applied widely inengineering practicality,but wind flow field around high-rise buildings can be simula-ted expediently by making use of the Computational Fluid Dynamics(CFD) software，obtaining wind pressure and wind velocity distribution of wind flow field,and evaluat-ing rationality of Architectural planning and structural design of tall buildings, at thesame time the rational improvements is put forward, which raise the quality of design.In this thesis,wind flow field around high-rise buildings in atmospheric boundarylayerare numerically simulated with software Fluent6.3. And the main research work is asfollows:(1)On the basis of widely consulting literatures domestically and abroad, thecurrent state of research about2D and3D numerical simulation analysis of flow fieldaround buildings are reviewed and summarized comprehensively. Focusing on thetheoretical basis of simulation of CFD software, some methods including controlequations, turbulence models, wall function, grid generation technique and the finitevolume method have been summarized systematically.(2)The numerical simulation of two-dimensional has been completed. Firstly, thestrouhal number, main frequency of resistance and lift coefficient are received fromthe analysis of numerical simulation on the single square cylinders, which meet theresult of the existing experiments and literatures. Simultaneously, the average windpressure coefficient and stream traces distribution is obtained. On the basis ofnumerical simulation on the single square cylinders, the characteristics of flow fieldaround the rectangular cylinders at the wind degree of zero and ninety(that is,considering the different aspect ratio of single column) has been simulated.Theinfluence rule of the aspect ratio on wind load and characteristics of flow around asingle column is obtained by comparing the results. Then with simulating thecharacteristics of wind flow around two square cylinders arranged in tandem andjuxtaposed,and comparing the results with the wind flow around single square cylinders, the study found that aerodynamic interference between two columnsarranged in tandem larger than it of two juxtaposed columns, aerodynamicinterference between two columns with different aspect ratio is larger than it withsame aspect ratio. When the two columns with different aspect ratio arranged intandem, aerodynamic interference between two square columns with small aspectratio at the first is smaller than it with large aspect ratio at the first.(3)Based on Reynolds Averaged Navier-Stokes Equations (RANS) model, the3Dsteady wind flow field around high-rise building was numerically simulated. Firstly,wind flow field around the standard model at the different wind flow degree of0°,15°,30°,45°,60°,75°and90°are simulated, receiving the average wind pressure coefficientof them.And compare them with the existing standard wind tunnel experiments. In thecase of relatively consistence of numerical simulations and wind tunnel experiments,get the shape coefficient of the windward,leeward and crosswind of building. And co-mpare them with the shape coefficient of rectangular over45meters that specificationgives for the further validation that the numerical simulation can meet the engineeringrequirements.(4)As numerical simulation of the standard model meet engineering requireme-nts,performing simulation on the King Building to obtain the average pressure coeffi-cient distribution and the flow field of it at the different wind flow degree of0°,45°,90°and135°. And compare the simulation results of the King Building with them ofstandard model, the study found that the wind field is improved when the building fa-cade is changed from a plane into the circular surface. At last, with the numerical sim-ulations of the three high-rise buildings arranged in tandem and juxtaposed with chan-ges in pitch, the study found that wind feild of three-building arranged in tandem andjuxtaposed is very different from it of a single building, aerodynamic interference bet-ween the buildings is reduced when the distance between them increases,aerodynamicinterference between three buildings arranged in tandem is larger than it of three juxt-aposed buildings, and aerodynamic interference is already very small when the distan-ce of the juxtaposed buildings is five and half times the feature length of the building.