Numerical Simulation Study Of Super High-rise Buildings In The Storm Field

The downburst is a strong subsidence flow developed under the rapid condensation of clouds.The wind speed of ground layer is obviously non-stationary,and the pressure gradient of the wind changes drastically.Therefore,it is particularly important to study the downburst pressure of super high-rise buildings.Based on the wall-jet model,the Reynolds Stress Model(RSM)was used to numerically simulate the super high-rise buildings in the downburst.The variation law of the pressure coefficient was found by using different wind speed conditions.At the same time,by comparing the lateral wind of the atmospheric boundary layer with vertical wind of downburst,the difference in wind pressure between each other could find.In addition,the influence of two typical podiums on wind pressure coefficients and aerodynamic coefficients of super high-rise buildings was studied and conclusions were listed as follows:(1)Simulating the downburst in Reynolds Stress Model(RSM)reflects well on the subsidence,impact,separation,and diffusion in whole life cycle,by which we can know the impact process and mechanism of downbursts.The results also show that the model has a good agreement with the three empirical wind profiles.(2)The heights of the different inflow boundaries from the ground have little effect on the vertical wind profile curve and the maximum radial velocity position.When the inlet boundary diameter is 600 meters,the radial velocity increases first and then decreases with height grows,and the maximum is about 600 meters radial distance and 70 meters height.(3)Sinking airflow generates vortices on the ground near the super high-rise buildings,which causes the pressure coefficient on the side of the building to show an extremum point that increases first and then decreases.The extreme points of 24m/s,29m/s,34m/s and 39m/s working conditions all appear at 180m=0.3H,which is the most unfavorable position of the wind-resistance design in the downburst storm.(4)Although the atmospheric pressure coefficient of the cross-border cross-border is generally greater than that of the down-flow storm,the down-burst flow is more threatening than the super-high-rise,which is mainly due to the impact of the secondary vortex on thedownburst field.On the side of the building,the pressure coefficient along the height of the building suddenly increases,which is particularly disadvantageous for the building height of0.3H.(5)The pressure coefficients exhibited by the two types of typical podiums tend to decrease with increasing height.All of them have obvious influence on the law of the pressure coefficient below the height of 0.5H above the super high-rise,and have little effect on the above 0.5H,indicating the podium.The effect of reducing and stabilizing wind pressure on the mid-lower parts of the super high-rise area disperses the adverse effects caused by the vortex generated by the strong subsidence airflow.