被动格栅紊流场横向风速相关性实验研究

EXPERIMENTAL RESEARCH ON COHERENCE OF LATERAL WIND VELOCITY IN PASSIVE GRID-GENERATED WIND FILED

被动格栅紊流场常用于各类风洞试验中,桥梁断面气动参数均与来流风参数有关。文中对顺风向脉动风速在不同水平间距和紊流积分尺度下的相关性进行实验研究,得出其与水平向间距和紊流积分尺度的比值相关。随着比值越大,其相关性变弱;顺风向脉动风速根方相干曲线随着水平间距增加,指数衰减曲线会在折减低频区会出现"掉头"的情况,并且给出在不同水平间距下更精确的拟合公式。

Passive grid-generated wind filed is commonly applied in various wind tunnel tests to obtain aerodynamic parameters of flexible bridge. Lateral root coherence function of along-wind turbulence component was investigated at different lateral distances and integral length scales. It is shown that the ratio of lateral distance to integral length scale is pivotal factor and the coherence decrease with the ratio. The curve of lateral root coherence function would ＂turns down＂at low reduced frequencies at certain distances,different root coherence function models are proposed at different distance.