A numerical investigation of two-degree-of-freedom VIV of a circular cylinder using the modified turbulence model

To simulate the fluctuating lift and resistance of the cylinder in vortex-induced vibration (VIV) accurately, the shear-stress transport (SST) turbulence model is modified in this paper. Then the correctness of the modified model is verified in the flow around a circular cylinder. After that, the numerical simulation of vortex-induced vibration of a cylinder with two degrees of freedom is carried out by using the embedded program of Open Foam under three different initial conditions which are uniform acceleration, uniform deceleration and uniform velocity respectively. After the comparison and analyses of the vibration amplitude, frequency, fluid force, motion locus and vortex shedding, we find that there are some differences in the results obtained under three initial conditions. By contrast, the results of uniform acceleration condition are more accurate. Besides, the hysteresis mechanism can be analysed on the basis of the vortex shedding characteristics of uniform acceleration and deceleration. In general, the initial condition has a great influence on the numerical simulation of the vortex-induced vibration, and the validity of the modified turbulence model is further verified in the simulation.