CFD Numerical Simulation Of Aerodynamic Characteristics Of Different Cross Section Tall Buildings In All Wind Directions

High-rise buildings are different from general architectures and their ability ofwind-resistance is becoming more and more prominent due to raised height ofbuilding. For years, wind-resistance evaluation for tall buildings is carried out mainlythrough wind tunnel test. Study on the aerodynamic characteristics of high-risebuilding by means of the numerical wind tunnel method has become anotherimportant research way with the rapid development of computer technology andcomputational wind engineering method. Currently, two-dimensional (2-D) and steadysimulation in wind engineering will be replaced by more accurate three-dimensional(3-D) and unsteady simulation. High-rise building’s aerodynamic shape has a greatinfluence on the wind-resistance ability of structure. However, there is little study onaerodynamic shape under different wind direction. Based on this, in this paper, flowfield characteristics around six different sections (square, rectangular and10%correctrate’s cut angle, concave angle section) under different wind direction will beobtained by used2-D numerical simulation. This paper mainly focuses the flow fieldcharacteristics around of different cross sections for tall building, and compares thedifferences between different cross sections. In this paper, the main research contentsand results are as follows:Firstly,2-D RANS k-ω SST model is employed to obtain the three-componentcoefficients, pattern of the pressure distribution and Strouhal number etc of differentcross sections under zero wind direction, and these results are compared with therelated literature to verify the fessibility of k-ω SST model.The effect of Reynoldsnumber of different cross sections are calculated and it is shown that in the subcriticalregion the three-component coefficients change a little with different Reynoldsnumber,and so it is Strouhal number.Secondly, three-component coefficients and Strouhal number are obtained.Squarecutting angle section and concave angle section can effectively reduce theaerodynamic drag.Square cutting angle section has a superior performance and itsaerodynamic drag is reduced about30%at low wind angle. With a increase of windangle, Strouhal number of rectangular cutting angle section and concave angle sectionbecome less and less and the mean drag coefficient under low wind direction issmaller than rectangular section.It is shown that the revised section can effectively reduce the aerodynamic drag.Finally, flow field characteristics around cylinder and two tall buildings with ascale of1:600are analyzed in3-D LES, and then flow field characteristics aroundsquare cylinder, rectangular cylinder and the revised section of the cylinder arecalculated. Three-component coefficients, pressure distribution coefficient andStrouhal number are obtained. It is shown that the results of mean pressuredistribution and flucutuating lift coefficient from3-D numerical simulation are muchmore exact corresponding to2-D numerical simulation and it verify the necessity of3-D numerical simulation.