气动干扰对平行双幅断面气动导纳影响研究

Aerodynamic interference effect on the aerodynamic admittance of paralleled double girders

针对平行双幅桥梁存在的气动干扰现象,采用节段模型测力风洞方法研究气动干扰效应对双幅断面气动导纳影响。结果表明,由于气动干扰作用,双幅断面气动导纳与单幅断面气动导纳存在一定差别,尤其阻力气动导纳;相同外形断面产生的气动干扰效应相似,不同外形断面产生的气动干扰效应不同;由于下游断面对上游断面气动干扰影响较弱,不同间距引起的气动干扰对上游断面气动导纳影响无明显规律;随间距的增大气动干扰对下游断面气动导纳影响逐渐减弱,间距足够大时,此影响可忽略不计。

The aerodynamic admittance describes the transfer behavior between wind spectra and buffeting forces spectra,which directly determines the precision of the buffeting response prediction.Due to the aerodynamic interference effect on the paralleled double bridges,the aerodynamic admittances of windward and leeward girders will be different from that of single girder.And the aerodynamic interference effect is related to the shapes of girders and distance between girders.An practical engineering was taken as a background,and the aerodynamic interference effect on the aerodynamic admittances was investigated by the method of sectional model force measurement in wind tunnel test.It is shown that there are some differences between the aerodynamic admittances of double girders and single girder because of the aerodynamic interference effect.The aerodynamic interference effect caused by girders with different shape of sections will be different.The aerodynamic interference caused by girders different distances apart affects the windward girder weakly, so there is no obvious change of the aerodynamic admittances of windward girder.With the increase of distance between windward and leeward girders,the aerodynamic interference effect on the aerodynamic admittances of leeward girder weakens gradually and can be ignored while the distance is large enough.