小宽厚比串列双矩形柱的气动干扰效应及产生机理OA北大核心CSTPCD

In order to study the aerodynamic interference effect and flow field mechanism of two tandem rectangular cylinders with a small aspect ratio,the aerodynamic force coefficients,wind pressure coefficient,Strouhal number,and flow field performance of the two cylinders with a width-thickness ratio B/D(the ratio of downwind width B to crosswind thickness D)of 1∶4 at different spacing ratios L/B(the ratio of center distance L of the two rectangular cylinders to downwind width B,the L/B varies from 1.2 to 8.0)were obtained by means of both wind tunnel test and large eddy simulation.The results of the two rectangular cylinders were compared with those of the single one.The results show that even if L/B reaches 8.0,the aerodynamic interference effect of the two rectangular cylinders is still not negligible.The mean drag coefficient of the upstream cylinder,the fluctuating lift coefficient of the downstream cylinder,and the Strouhal number of both cylinders exhibit varying levels of amplification effect,with the maximum being 1.4 times,2.1 times,and 1.2 times of the single one,respectively.When L/B＜4.0,the flow exhibits a single bluff body flow pattern.The formation of separation bubbles between the two cylinders is the reason for the increase of the negative mean wind pressure coefficient and local fluctuating wind pressure coefficient on the gap surface of the two rectangular cylinders.While L/B ≥4.0,a shear layer reattachment flow pattern appears.Intermittent reattachment of the shear layers causes an increase in the local fluctuating wind pressure coefficient on the side surface of the downstream rectangular cylinder.