Secondary Vortex Interactions in the Collision of a Vortex Ring upon a Wavy Wall

Vortex-wall interactions are a widely studied fluid interaction in, for example, cardiovascular flows, insect flight, and heat transfer. Previously literature, limited to 2D vortex interactions, reveals that wavy surface perturbations introduce a phase offset in the generation and evolution of secondary vorticity, leading to complex vortex-vortex interactions. The goal of this study is to investigate the interaction of a vortex ring upon a wavy wall to establish a generic survey into 3D vortex-pertubred-surface interactions . This work employs an experimental approach in which a vortex ring of one formation number impinges on sinusoidal surface plates, varying in amplitude and wavenumber, across a range of Reynolds numbers, Re_Γ 1450 to 2200. Preliminary findings indicate that low wavenumber perturbations introduce a looping secondary vortex tube, while higher wavenumber plates introduce individual secondary hairpin vortices for each perturbation. Meanwhile, amplitude controls the timing of the vortex-vortex interactions, with higher amplitudes leading to quicker interactions. Further insight into the mechanisms which drive this evolution will be explored as well as the ability of these unique structures to enhance or deter structural persistence. This work is noteworthy as a novel investigation on a fundamental and widely-applicable flow structure and provides important insight into vortex-vortex interactions and breakdown.