Effects of Reynolds number and scale ratio on VIV tests for railway blunt box girders

Blunt steel box girder as a form of main girder used in large-span railway bridges, the vortex-induced vibrations (VIVs) phenomenon is significant. In order to investigate the effect of model scale on the test results of section model VIV tests of railway bridge blunt box girders, 1:90, 1:50 and 1:25 section model wind tunnel tests were carried out. The test results show that the VIV experimental results are greatly affected by the scale of the model, in which the amplitudes obtained from the 1:50 model test is the most significant, and the VIV characteristics of the two scale models of 1:50 and 1:25 coincide with each other roughly; However, the 1:90 small-scale model is not able to effectively respond to the VIV characteristics of the real bridge. The CFD numerical simulation results also confirm the phenomenon that the 1:90 small-scale model test cannot effectively respond to the real VIVs characteristics. Although VIVs, obtained in a small-scale model test, are not possible to determine the vibration response of the actual railway bridge, it can be used to compare the VIV performance of the cross-section and to assist in the study of aerodynamic optimization measures at the early design stage.