FLOW-INDUCED VIBRATIONS OF A SQUARE CYLINDER WITH COMBINED TRANSLATIONAL AND ROTATIONAL OSCILLATIONS

In this work, we investigate the combined translation and rotational flow-induced vibration (FIV) of elastically mounted square cylinder in a free-stream at zero incidence angle. We employ a partitioned iterative scheme to solve coupled fluid-rigid body interaction using unstructured grid. The fluid-solid coupled solver and the mesh is verified by investigating pure translational motion cases at zero incidence against published data for a laminar flow past a square cylinder. Further analysis revealed that the increase of mass ratio shifts the lock-in to higher reduced velocity region. The influence of of the torsional motion parameters is analyzed for a pure rotational case. The combined 3-DOF motion is next considered while keeping the above two analyses as reference. It was evident that, even small yaw vibrations adds circulation to the flow and thus increases the vortex intensity. This phenomenon is identified to be responsible for the differences of motion parameters between the isolated DOF cases and combined 3DOF cases. Finally, for the completeness of the study, the influence of 3D effects is estimated for the same geometry and also a high Re case is presented.