Transverse and Rotational Galloping of Square Cylinders at Low Reynolds Numbers

The occurrence of simultaneous translational and rotational galloping of a square cylinder is assessed through two-dimensional fluid-structure interaction simulations. A finite element formulation specifically designed for fluid-structure interaction simulations has been used. The response characteristics depend on Reynolds number, mass ratio, inertia ratio, structural damping ratio, reduced velocity for both motions transverse and in rotation. The free angular and translational responses of the square cylinder mounted on torsional and translational springs in cross-flow are obtained from fully coupled fluid-structure simulations. Present results have been obtained for a fixed rotation inertia ratio to mass ratio of 1/6. This has the effect of favoring rotation motions over translation. Also to keep the 2D assumption realistic, we stick to a low value of 200 of the Reynolds number.