The Effect Of Turbulence Characteristics On Wind Load Of High-Rise Buildings With Round Section

High-rise buildings are sensitive to wind load.There are more and more round and oval high-rise buildings for aesthetic and creative needs.The classical problem of flow around circular cylinder is mostly carried out in the uniform flow field.In this paper,in order to study the effect of turbulence characteristics on wind load of a tall buildings with round section,a passive simulation device for wind tunnel test was designed independently,the effects of each parameter of passive simulation device on turbulence characteristics were studied under separate or combined conditions.Based on these rules,a class of CI wind field with constant turbulence integral scale and 3% increase in turbulence intensity,two types of CL1 wind field and CL2 wind field with constant turbulence intensity but decreasing turbulence integral scale have been successfully adjusted.Based on the wind tunnel test,the pressure measurement tests were carried out by using the circular rigid model under four kinds of wind fields,and the influence of the singleparameter change of the turbulence characteristics on the surface wind pressure,the layer wind force and its coherence,the base moment coefficient and the power spectrum were studied.The ruselts show that:The turbulence characteristics have little effect on the general law of the average wind pressure distribution of the whole building.With the increase of turbulence intensity,the absolute values of average wind pressure coefficient and fluctuating wind pressure coefficient at the edge of the model increase.The influence of the decrease of the turbulence integral scale on the fluctuating wind pressure coefficient was mainly concentrated on the leeward side.The smaller the turbulence integral scale was,the smaller the absolute value of fluctuating wind pressure coefficient was.By studying the influence of turbulence characteristics on the wind force of circular crosssection high-rise buildings,it was found that with the increase of turbulence intensity,the average layer resistance coefficient decreases,the layer fluctuation resistance coefficient and layer fluctuation lift coefficient increase,but it had little effect on the correlation coefficient of layer fluctuation resistance coefficient and layer fluctuation lift coefficient.With the increase of turbulence intensity,the attenuation rate of coherence function and the pulsating lift coherence function of circular buildings slows down.With the decrease of the turbulence integral scale,the laminar average and fluctuating resistance coefficients tend to decrease,and the smaller the integral scale is,the greater the decrease of the resistance coefficient is,and the worse the cross-correlation of the laminar fluctuating resistance coefficients in the higher and lower positions of the model is.The turbulent integral scale in the test range could ignore the laminar fluctuating lift coefficient and the crosswind base bending moment coefficient.Meanwhile,in order to compare the influence of turbulence characteristics with Re,the wind pressure and wind force at four types of wind fields with different turbulence characteristics and a uniform wind field in TrSL3 region were studied.The results show that in TrSL3 region,under uniform wind field,the average wind pressure coefficient of resonant region height does not change with the increase of Re,and has no effect on the average drag coefficient.When Re=20.7K,under C wind field,the average wind pressure coefficient at the height of resonance region has a "single-sided bulge" phenomenon similar to the "single-sided bubble";with the increase of turbulence intensity,in the CI wind field,the phenomenon of mean wind pressure coefficient disappears,while a similar phenomenon of the pulsating wind pressure coefficient shows up.Under the influence of turbulence characteristics,the average drag coefficients of each layer decrease with the increase of Re.In CI wind field and CL1 wind field,within the range of 20.7K～41.4K Reynolds number,the average drag coefficients have a significant increasing trend,but when the Reynolds number continues to increase,within the range of 41.4K～96.6K,the average drag coefficients maintains a decreasing trend;The more the turbulence integral scale decreases,the more obvious the average drag coefficient decreases with the increase of Re.