Numerical investigation on vertical vortex-induced vibrations of triple-box girders with curved and linear-type webs

This article presents a numerical study of the vertical vortex-induced vibration (VIV) of bare triple-box girders with both curved and linear-type webs. The simulation was carried out at Scruton number of Sc = 4 pi m zeta/rho BD = 3.34 with the Reynold number from 1.35 x 105 to 8.09 x 105. The CFD simulation model is verified with data from wind tunnel tests. VIV occurs for both sections at low reduced wind speed (0.30.4). The dynamic responses, pressure distribution, flow field, and aerodynamic work distribution during VIV for both sections are portrayed in detail. The results indicate that during the stable VIV stage for the linear-type-web section, the vortex structures around the tail of the middle box and the downstream gap exhibit differences between the two adjacent oscillation periods, resulting in the sub-harmonic components in the aerodynamic lift force. Additionally, the fluctuating pressure on the linear-type web section is greater than on the curved web section due to more separated points on the linear-type web section. For both web types, the primary excitation source for the VIV is the vortices that periodically impinge on the leading surface region on the top of the middle box, resulting in the main energy input.