AnotineBDr. Antoine Blanchard,
PhD Student, Department of Aerospace Engineering, University of Illinois at Urbana-Champaign
Laminar vortex-induced vibration of a circular cylinder with nonlinear energy sinks

Thursday, Mar 23, 2017, 1:00pm to 2:00pm | Room 1-371

We consider two-dimensional laminar flow past a linearly-sprung cylinder undergoing rectilinear vortex-induced vibration (VIV) normal to the mean flow, with an attached "nonlinear energy sink" (NES). We show that a "rotational NES" (consisting of a mass allowed to rotate about the cylinder axis, and whose rotational motion is linearly damped by a viscous damper) gives rise to a variety of phenomena not seen in VIV with no NES, including partial stabilization of the vortex street formed downstream of the cylinder, drag reduction, and coexistence of multiple long-time solutions. We also show that a "translational NES" (consisting of a mass allowed to translate in the direction of travel of the cylinder, and whose rectilinear motion is restrained by an essentially cubic spring and a linear viscous damper) leads to complete and partial VIV-suppression mechanisms, relaxation cycles, as well as Hopf and Shilnikov bifurcations. For both configurations, the computational results are investigated analytically using reduced-order models of the fluid-structure interaction, thus providing insight into the nonlinear dynamics of the infinite-dimensional coupled system.

Short Bio:

Antoine Blanchard is currently a Ph.D. candidate in the Department of Aerospace Engineering at the University of Illinois (Urbana-Champaign) where he works under the supervision of Professors Lawrence Bergman and Alexander Vakakis. His thesis project focuses on computational and analytical studies of vortex-induced vibration of bluff bodies with nonlinear and dissipative attachments. Prior to joining Illinois, Antoine received his B.S. and M.S. degrees from the Ecole Centrale de Lille, one of the top "Grandes Ecoles" in France.