Suppression of vortex-induced vibration of single-box girder with various angles of attack by self-issuing jet method

Wind tunnel tests were conducted to investigate the effect of the self-issuing jet flow control on the vortex-induced vibrations (VIVs) of a streamline single-box girder at various angles of attack (AOAs). Spanwise periodic passive slits were symmetrically arranged on the windward and leeward lower inclined panels of the girder. The Reynolds number varied from 4.19 x 10(4) to 1.14 x 10(5), and the AOA varied from -5.0 degrees to 5.0 degrees with increments of 2.5 degrees. The vibration response characteristics of the girder with different slit arrangements were discussed, and the interactions between the shedding Karman vortices (KVs) and passive jets were investigated. The results show that the self-issuing jet control method could effectively suppress the VIV; the slits on the upper part of the lower inclined panel showed the best effect (Case I) at various AOAs. In addition, the large shedding KV were modified into two kinds of vortices: a reduced shedding KV and standing vortex at the trailing bottom corner of the girder. When the shedding vortex generation was displaced downstream, a second instability occurred in the near-wake. The self-issuing jets worked better at positive AOAs because more than one slit rows controlled the shedding vortices. Finally, the flutter performance of the single-box girder with self-issuing jets was investigated; Case I had a positive effect on the flutter behaviour at AOAs of -2.5 degrees to 5 degrees; the same flutter performance was observed at -5 degrees. (C) 2020 Elsevier Ltd. All rights reserved.