Numerical Simulation Of Moving Downburst And Its Effect On High-rise Building

In recent years,the global climate has deteriorated and the frequency of downburst has increased.Downburst is a kind of natural disaster that breaks out near the ground,and it has characteristics of short life cycle and randomness.Moreover the strong air flow generated by the downburst will cause catastrophic consequences.However,the current load specification in China consider the atmospheric boundary layer wind load when it comes to structural wind resistance design,and it do not take the extreme weather of the downburst into consideration.Therefore,it is very necessary for us to study and analyze the characteristics of the downburst wind field.CFD software is often used for the numerical simulation.The numerical simulation of the downburst in this thesis is based on the impinging jet model and the SST k-?turbulence model.Firstly,the article conducts a three-dimensional steady-state numerical simulation of a static downburst storm to study the wind field characteristics and the influence on the buildings at the center of the jet.Then,the numerical simulation of the moving downburst based on the sliding grid technology is aim to study the approximate real downburst wind field and the influence on high-rise building.By this way,we can obtain the influence of radial wind speed profile,wind speed history curve,and overall movement of downburst on the pressure coefficient of the building surface.Finally,a comparison is made between the stationary downburst and the moving downburst.The results show that the radial velocity of the downburst increases approximately linearly with the increase of the radial distance.The position of the extreme wind speed appears in the near-surface height range,and the distance from the center of the jet isr?28?1.0D_jet.The radial velocity reaches the extreme wind velocity and radial wind speed gradually decreases with the increasing radial distance,which is completely different from the wind in the atmospheric boundary layer.With the aid of the sliding grid technology,the basic characteristics of the moving downburst storm wind field can be well simulated.The overall movement of the downburst has an increasing effect on the wind speed in the moving direction?positive direction?,a weakening effect on the radial wind speed in the negative direction,and an increase in the pressure coefficient on the surface of the building.