The Effect Of Turbulence Characteristics On Wind Loads Of Square Tall Buildings

Wind disaster is a common natural disaster.The strong wind or typhoon that caused economic losses in China in recent years are as follows:“Rainbow”,“Mangosteen”and“Lekima”.At present,although there is no report on the collapse of high-rise buildings due to the destruction of the main structure under the action of Strong wind or typhoon,the envelope structure is seriously damaged and the high-rise buildings are frequently shaken,the characteristics of incoming wind have a great influence on the wind load distribution of high-rise buildings,the range of turbulent integral scale is large and the intensity of turbulence is large.Therefore,it is necessary to study the effect of incoming turbulence on wind loads of high-rise buildings.In this paper,the wind field in the boundary layer with five different turbulent characteristics is tested by using the combination of rectangular plate and rough element,and then the large eddy simulation(LES)method is used to simulate the wind field in the wind tunnel,three kinds of boundary layer turbulence are generated by using DSRFG method,and the wind load characteristics of high-rise buildings are studied by using turbulence intensity and turbulence integral scale as a single variable,the influence of turbulence characteristics on wind pressure and wind force characteristics of high-rise buildings is studied.Through wind tunnel tests,the influence of incoming flow turbulence characteristics on the wind load characteristics of high-rise building surface is studied.The wind pressure and wind coefficient,power spectrum,extreme wind pressure,correlation and coherence are studied.The results show that the turbulence characteristics have little influence on the mean wind pressure coefficient,and have obvious influence on the rms wind pressure coefficient.The influence of turbulence intensity is more obvious.Turbulence intensity is the main influencing factor of rms wind pressure on windward side,and turbulence integral scale has little effect on rms wind pressure on windward side.The power spectrum of rms wind pressure at measuring points on the side wind surface has obvious main peak value,and the main peak of wind pressure spectrum increases with the decrease of turbulence integral scale.With the increase of turbulence intensity,the main peak of wind pressure spectrum becomes shorter,the energy of low frequency range increases,and the range of energy with frequency becomes wider.With the increase of turbulence intensity,the mean layer,rms resistance,rms lift coefficient and rms base bending moment coefficient in downwind and torsional directions increase;the peak value and Strouhal number of crosswind layer rms wind power spectrum decrease,and the variation of base force power spectrum is similar to that of corresponding layer rms wind.The correlation between crosswind direction and torsional base moment is enhanced;with the decrease of turbulence integral scale,the layer mean,rms drag coefficient and base bending moment coefficient along the wind direction decrease,and the rms lift and torque coefficient change little.Based on the wind tunnel test results,the validity of LES method is demonstrated.Based on the large eddy simulation method,the influence of inflow turbulence characteristics on the surface wind load characteristics of high-rise buildings is studied,and the wind pressure,flow field information and vortical distribution on the structure surface are analyzed.The results show that with the increase of turbulence intensity and turbulence integral scale,the mean wind pressure coefficient of high-rise buildings does not change significantly,and the rms wind pressure coefficient increases.The incoming flow separates at the leading edge and forms a wide wake,and the leeward surface forms a large area of recirculation zone,and the rms motion increases.Turbulence characteristics have important effects on fluid separation,wake width and vortex structure.The surface vorticity of high-rise buildings increases with the increase of turbulence intensity and decreases with the increase of turbulence integral scale,but large-scale shedding vortex is formed above the model.