Study On Wind Pressure Distribution Characteristics Of Opening Building Surface Under Downburst

In recent years,downburst occurs more frequently with the deterioration of global climate.Downburst is a kind of thunderstorm gale occurring near the ground.It has a short life cycle and randomness.It forms a strong downdraft in thunderstorm weather.It strikes the ground violently from a certain height of the atmosphere in a very short time,and accelerates its expansion from the impact area to the surrounding areas.It often causes serious damage or even collapse of a large number of engineering structures.However,the current wind load code of our country only focuses on the good wind load in the atmospheric boundary layer,and does not consider the impact of thunderstorm extreme weather on buildings.Therefore,it has important theoretical significance and engineering application value to study the characteristics of downburst action.Firstly,based on the CFD numerical analysis method of RNG k-? turbulence model,the accuracy of the numerical simulation method is verified by the existing experimental data.Through the analysis and comparison of the downburst wind profiles obtained by simulation and test,it is shown that RNG k-? turbulence model can better simulate the basic characteristics of downburst wind field and can be used as an effective method to study the wind field effect of such buildings.Secondly,the CFD numerical method is used to simulate the wind load effect of the single-slope open-span building,and the building is located at the maximum radial velocity(r/D=1.0).The influence of the opening rate,the number of open faces,the location of opening and roof angle on the distribution of wind load inside and outside the building surface are analyzed;At the same time,considering the influence of oblique wind on the local wind pressure distribution inside and outside each facade of a double-slope roof opening building,the distribution law of wind pressure inside and outside each local area of the fa?ade in the oblique wind is obtained.The results show that the variation of the opening rate,the number of openings,the location of opening and the angle of the roof slope have a greater impact on the internal pressure of the building than the external pressure.Under the action of the oblique wind,the internal and external wind pressure of the building changes greatly,the pressure of partition zones increases or decreases more.Finally,the interference effects of two rows and one row of sloping roof buildings in downburst wind field are studied.Taking the tandem layout of two double-slope roof buildings as the object of study,considering the variation of the disturbing roof slope angle,the number of openings,the ratio of length to width,the ratio of height to width and the net spacing,the disturbing effects of above factors on wind pressure on the facades and roofs of the disturbed buildings are analyzed and the relevant laws of the disturbing effects of internal and external wind loads on the different facades and roof zones of the disturbed buildings are obtained.The results show that the wind load distribution characteristics of the disturbed buildings under the tandem layout are significantly different from isolated buildings,and the wind pressure on the disturbed buildings surface shows a significant change law with the change of different conditions,The wind pressure in some areas changes from negative to positive,which has a greater impact on the external pressure of the disturbed buildings.