Study of the applicability of different turbulence models in simulating vortex-induced vibration of a rectangular cylinder

In this research, the practical applicability of LES, SST-DES and SST-URANS turbulence models to vortex-induced vibration (VIV) problems is investigated by employing a rectangular 5:1 cylinder as the study object. The efficacy of each model in predicting the displacement response, characterizing integrated aerodynamic forces, analyzing vortex shifting over the cylinder surface, and examining three-dimensional flow field effects is thoroughly assessed. The distribution characteristics and phase changes of aerodynamic force and flow field modes under vortex shedding frequency are analyzed based on the DMD method. All three turbulence models can accurately reproduce the lock-in phenomenon of VIV. The VIV response calculated by SST-DES is similar to experimental results and computation efficiency is improved by combining the features of LES and RANS. However, it is still challenging for SST-DES to capture the high-order vortex shedding frequency components of the flow fields in a similar manner to LES. In the SST-URANS simulation, greater work done by aerodynamic force leads to a larger steady-state amplitude. SST-URANS has difficulty in capturing small-scale vortex structures in the flow field and the main vortex location is closer to the leading edge than those obtained by LES and SST-DES. Compared with the results of LES, both SST-DES and SST-URANS overestimate the spanwise correlation of aerodynamic force, while SST-URANS weakens the three-dimensional effects of the flow fields, and the simulated vortex structure only exhibits a two-dimensional distribution. The simulation results supply data support and reference for the selection of turbulence models in the VIV simulations of prolate rectangular cylinders or bridges.