Investigation of Fluid-Structure Interactions on Controlled Oscillations of a Cylinder at Moderate Reynolds Number

This paper focuses on the flow dynamics associated with uniform flow past an oscillating cylinder using a 2D Computational Fluid Dynamics (CFD) approach. The simulations were carried out using the Reynolds-Averaged Navier-Stokes (RANS) k-w turbulence model. The numerical model has been validated with experimental data to ensure accuracy of the results. The results were examined for Re = 10,000 and a fixed motion amplitude ratio of A/D = 0.3 and the frequencies of the oscillations were varied in the vicinity of the Strouhal frequency of a fixed cylinder in a free stream. It is noted that a phase switch of the vortex formation will occur as the frequency of the oscillation passes through the Strouhal cylinder frequency. This transition is characterized by a jump in the in-phase and out-of-phase with the velocity components of the forces. The results were examined by analyzing the transfer of energy either from the fluid to the structure or vice versa to quantify the jump in the force components. In the lock-in region, a limit cycle of the cylinder motion and the lift force will form. The energy transfer is then related to the traverse direction of the limit cycle.