72th Annual Meeting of the APS Division of Fluid Dynamics (November 23, 2019 — November 26, 2019)

V0056: Down to the Wire: A Story of a Vortex Ring Collision

Authors

• Mary Agajanian, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
• Ryan McKeown, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
• Joel W. Newbolt, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
• Aakash Mishra, Department of Mechanical Engineering, University of Houston, Houston, Texas 77204, USA
• Rodolfo Ostilla-Mónico, Department of Mechanical Engineering, University of Houston, Houston, Texas 77204, USA
• Shmuel M. Rubinstein, School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA

DOI: https://doi.org/10.1103/APS.DFD.2019.GFM.V0056

When a dyed vortex ring collides head-on with a wire, it undergoes a beautiful transformation as it sheds its outer layers into two secondary “elephant ears.” These secondary “ears” are swept behind by the original vortex ring as it continues forward. This model system is ideal for probing the complex interactions between vortices and rigid bodies. We visualize the complete 3D dynamics of this flow by scanning over the dyed vortex ring with a laser sheet as the ring interacts with the wire. These visualizations, combined with careful simulations, show that the secondary “ears” result from local shedding of vorticity from the wire, which interacts with the original vortex ring.