CFD Numerical Simulation Of Tornado Wind Field And Its Impact Of Wind Loads On Building

Wind-induced disaster and loss become more and more serious all over the world, and this loss is the largest among all the natural disasters according to domestic and overseas statistical data. For long span, flexible and light weight building, wind load is a critical factor in the process of design. Many scholars have carried out a lot of researches about typhoon and downburst, but the research about tornado is still few. Currently, Chinese architectural design standard doesn't put forward the specific law about the influent of tornado to the buildings. So it is necessary to carry out some research about the influent of tornado to the buildings.In this thesis, analysis of tornado wind field is carried out by vortex theory, then numerical simulate tornado wind field is conducted by CFD software (FLUENT 6.3). After that, the parameters which may give rise to influence to wind field are analyzed. At last, building is put in the tornado wind field to carry out the research about the influence of tornado wind to the surface pressure of building.The influence of tornado to buildings reflects in negative pressure and tangential velocity mainly. In one height, tangential velocity along radial direction has a maximum and the corresponding radius is named core radius. The tangential velocity decreases with the distance out of core radius. In addition, wind pressure and velocity have little change with the change of height. For proving the rationality of numerical simulation wind field, the distribution curves of numerical simulation wind speed in radial direction and tangential direction are compared with the curves of theoretical formulas.In order to improving the accuracy of numerical simulation tornado wind field by CFD, the parameters which may impact tornado wind field are analyzed. According to change of the size of wind field, direction of entrance and initial wind speed of entrance, the maximum tangential direction wind speed and core radius in the same height are analyzed and compared with each other so that more suitable numerical simulation model for tornado generator can be found.Finally, building model is placed in the tornado wind field and the analysis about the distribution of surface wind pressure of building is carried out. It will provide technical basis for design of civil buildings and nuclear industrial buildings.